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  • Agro-ecosystem & Environment
    Hubing Zhao, Guanfei Liu, Yingxia Dou, Huimin Yang, Tao Wang, Zhaohui Wang, Sukhdev Malhi, Adnan Anwar Khan
    Journal of Integrative Agriculture. 2024, 23(9): 3174-3185. https://doi.org/10.1016/j.jia.2024.01.008
    Amplifying drought stress and high precipitation variability impair dryland wheat production.  These problems can potentially be minimized by using plastic mulch (PM) or straw mulch (SM).  Therefore, wheat grain yield, soil water storage, soil temperature and water-use productivity of PM and SM treatments were compared with no mulch (CK) treatment on dryland wheat over a period of eight seasons.  Compared to the CK treatment, PM and SM treatments on average significantly increased grain yield by 12.6 and 10.5%, respectively.  Compared to the CK treatment, SM treatment significantly decreased soil daily temperature by 0.57, 0.60 and 0.48°C for the whole seasons, growing periods and summer fallow periods, respectively.  In contrast, compared to the CK treatment, PM treatment increased soil daily temperature by 0.44, 0.51 and 0.27°C for the whole seasons, growing periods and summer fallow periods, respectively.  Lower soil temperature under SM allowed greater soil water storage than under PM.  Soil water storage pre-seeding was 17% greater under the SM than under the PM treatment.  Soil water storage post-harvest was similar for the PM and SM treatments, but evapotranspiration was 4.5% higher in the SM than in the PM treatment.  Consequently, water-use productivity was 6.6% greater under PM than under the SM treatment.  Therefore, PM treatment increased dryland wheat yield and water-use productivity, while straw mulch increased soil water storage.


  • Agro-ecosystem & Environment
    Delei Kong, Xianduo Zhang, Qidong Yu, Yaguo Jin, Peikun Jiang, Shuang Wu, Shuwei Liu, Jianwen Zou
    Journal of Integrative Agriculture. 2024, 23(9): 3159-3173. https://doi.org/10.1016/j.jia.2024.03.047
    Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields, but significantly stimulate nitrous oxide (N2O) emissions because of variations in soil oxygen level and redox potential.  However, the relationship linking soil N2O emissions to nitrogen functional genes during various fertilization treatments in water-saving paddy fields has rarely been investigated.  Furthermore, the mitigation potential of organic fertilizer substitution on N2O emissions and the microbial mechanism in rice fields must be further elucidated.  Our study examined how soil N2O emissions were affected by related functional microorganisms (ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), nirS, nirK and nosZ) to various fertilization treatments in a rice field in southeast China over two years.  In this study, three fertilization regimes were applied to rice cultivation: a no nitrogen (N) (Control), an inorganic N (Ni), and an inorganic N with partial N substitution with organic manure (Ni+No).  Over two rice-growing seasons, cumulative N2O emissions averaged 0.47, 4.62 and 4.08 kg ha−1 for the Control, Ni and Ni+No treatments, respectively.  In comparison to the Ni treatment, the Ni+No fertilization regime considerably reduced soil N2O emissions by 11.6% while maintaining rice yield, with a lower N2O emission factor (EF) from fertilizer N of 0.95%.  Nitrogen fertilization considerably raised the AOB, nirS, nirK and nosZ gene abundances, in comparison to the Control treatment.  Moreover, the substitution of organic manure for inorganic N fertilizer significantly decreased AOB and nirS gene abundances and increased nosZ gene abundance.  The AOB responded to N fertilization more sensitively than the AOA.  Total N2O emissions significantly correlated positively with AOB and nirS gene abundances while having a negative correlation with nosZ gene abundance and the nosZ/nirS ratio across N-fertilized plots.  In summary, we conclude that organic manure substitution for inorganic N fertilizer decreased soil N2O emissions primarily by changing the soil NO3-N, pH and DOC levels, thus inhibiting the activities of ammonia oxidation in nitrification and nitrite reduction in denitrification, and strengthening N2O reduction in denitrification from water-saving rice paddies.


  • Animal Science · Veterinary Medicine
    Gang Lu, Feiyan Zheng, Yuqing Xiao, Ran Shao, Jiajun Ou, Xin Yin, Shoujun Li, Guihong Zhang
    Journal of Integrative Agriculture. 2024, 23(9): 3145-3158. https://doi.org/10.1016/j.jia.2023.11.008

    Recently, increasing natural infection cases and experimental animal challenge studies demonstrated domestic cats are susceptible to multiple subtypes influenza A virus (IAV) infections.  Notably, some subtype IAV strains could circulate in domestic cats after cross-species transmission and even infected humans, posing a threat to public health.  Host factors related to viral polymerase activity could determine host range of IAV and acidic nuclear phosphoprotein 32 (ANP32) is the most important one among them.  However, role of cat-derived ANP32 on viral polymerase activity and host range of IAV is still unknown.  In the present study, a total of 10 feline ANP32 (feANP32) splice variants (including 5 feANP32A, 3 feANP32B, and 2 feANP32E) were obtained from domestic cats by RT-PCR.  Sequence alignment results demonstrated amino acid deletions and/or insertions occurred among feANP32 variants, but all feANP32 proteins were primarily localized to cell nucleus.  Minigenome replication systems for several representative IAV strains were established and the support ability of feANP32 on IAV polymerase activity was estimated.  The results indicated that most feANP32A and feANP32B splice variants were able to support all the tested IAV strains, though the support activity of a single feANP32 protein on polymerase activity varied among different IAV strains.  In addition, the role of feANP32 in supporting H3N2 canine influenza virus was determined by investigating viral replication in vitro.  Collectively, our study systematically investigated the support activity of feANP32 on IAV, providing a clue for further exploring the mechanism of susceptibility of cats to IAV.

  • Animal Science · Veterinary Medicine
    Yajun Zhang, Xiao Chang, Bing Wang, Dawei Wei, Rongzhen Zhong, Yansheng Guo, Min Du, Guijie Zhang
    Journal of Integrative Agriculture. 2024, 23(9): 3129-3144. https://doi.org/10.1016/j.jia.2023.10.008

    Lycium barbarum residue (LBR), a by-product of L. barbarum processing, is packed with bioactive components and can be potentially utilized as a feed additive in animal husbandry.  However, the fundamental understanding of its effectiveness on livestock animals is still lacking, particularly in ruminants.  To explore the effects of LBR on the growth performance, rumen fermentation parameters, ruminal microbes and metabolites of Tan sheep, sixteen fattening rams (aged 4 mon) were fed a basal diet (CON, n=8) or a basal diet supplemented with 5% LBR (LBR, n=8).  The experiment lasted for 70 d, with 10 d adaptation period and 60 d treatment period.  The results showed that the LBR enhanced the average daily feed intake, average daily gain (P<0.05), and ruminal total volatile fatty acids (P<0.01) while decreasing ammonia-nitrogen concentration and rumen pH value (P<0.05).  Additionally, the LBR improved the relative abundances of Prevotella, Succiniclasticum, Ruminococcus, Coprococcus, Selenomonas, and Butyrivibrio (P<0.05) and reduced the relative abundances of Oscillospira and Succinivibrio (P<0.05).  The LBR altered the ruminal metabolome (P<0.01) by increasing the abundances of ruminal metabolites involved in amino acids (e.g., L-proline, L-phenylalanine, L-lysine, and L-tyrosine), pyrimidine metabolism (e.g., uridine, uracil, and thymidine), and microbial protein synthesis (e.g., xanthine and hypoxanthine).  In conclusion, LBR had positive effects on the growth rate of Tan sheep as well as on rumen fermentation parameters, rumen microbiome and rumen metabolome.

  • Animal Science · Veterinary Medicine
    Yuting Zhu, Yongli Wang, Yidong Wang, Guiping Zhao, Jie Wen, Huanxian Cui
    Journal of Integrative Agriculture. 2024, 23(9): 3118-3128. https://doi.org/10.1016/j.jia.2023.04.015
    Excessive abdominal fat deposition reduces the feed efficiency and increase the cost of production in broilers.  Therefore, it is an important task for poultry breeders to breed broilers with low abdominal fat.  Abdominal fat deposition is a highly complex biological process, and its molecular basis remains elusive.  In this study, we performed transcriptome analysis to compare gene expression profiles at different stages of abdominal fat deposition to identify the key genes and pathways involved in abdominal fat accumulation.  We found that abdominal fat weight (AFW) increased gradually from day 35 (D35) to 91 (D91), and then decreased at day 119 (D119).  Accordingly, after detecting differentially expressed genes (DEGs) by comparing gene expression profiles at D35 vs. D63 and D35 vs. D91, and identifying gene modules associated with fat deposition by weighted gene co-expression network analysis (WGCNA), we performed intersection analysis of the detected DEGs and WGCNA gene modules and identified 394 and 435 intersecting genes, respectively.  The results of the Gene Ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that the steroid hormone biosynthesis and insulin signaling pathways were co-enriched in all intersecting genes, steroid hormones have been shown that regulated insulin signaling pathway, indicating the importance of the steroid hormone biosynthesis pathway in the development of broiler abdominal fat.  We then identified 6 hub genes (ACTB, SOX9, RHOBTB2, PDLIM3, NEDD9, and DOCK4) related to abdominal fat deposition.  Further analysis also revealed that there were direct interactions between 6 hub genes.  SOX9 has been shown to bind to proteins required for steroid hormone receptor binding, and RHOBTB2 indirectly regulates the steroid hormones biosynthesis through cyclin factor, and ultimately affect fat deposition.  Our results suggest that the genes RHOBTB2 and SOX9 play an important role in fat deposition in broilers, by regulating steroid hormone synthesis.  These findings provide new targets and directions for further studies on the mechanisms of fat deposition in chicken.  


  • Plant Protection
    Xianliang Huang, Dai Shi, Kai Deng, Shuzhen Jia, Ding Ding, Li Hou, Bing Chen
    Journal of Integrative Agriculture. 2024, 23(9): 3104-3117. https://doi.org/10.1016/j.jia.2024.03.019
    Drought events have become more severe under climate change, and this can pose a major threat to the survival of various organisms.  The molecular mechanisms involved in dehydration resistance are not well known.  Here, adults of the migratory locust, Locusta migratoria, were subjected to food-mediated dehydration, and adipokinetic hormone (AKH) signaling was found to play a key role in regulating dehydration resistance.  Specifically, dehydration shortened the lifespan, increased the body weight loss, and reduced the water loss rate in adult locusts.  Global transcriptome profiles revealed variations in tissue-specific gene expression between dehydration-resistant locusts and normal locusts.  Importantly, dehydration selection and exposure induced prominent expression of AKH genes in the retrocerebral complex of adult locusts.  Furthermore, individual knockdown of AKH1, AKH2, or AKH receptor (AKHR) accelerated water loss and shortened the lifespan of adult locusts under dehydration conditions, and trehalose supplementation ameliorated the negative effects caused by interference with AKH or AKHR.  These findings demonstrated that AKH/AKHR signaling-dependent trehalose metabolism plays a crucial role in regulating locust dehydration resistance and thus provide novel insights into the regulatory mechanism underlying drought resistance.


  • Plant Protection
    Shanyu Li, Guifang Lin, Haoqi Wen, Haiyan Lu, Anyuan Yin, Chanqin Zheng, Feifei Li, Qingxuan Qiao, Lu Jiao, Ling Lin, Yi Yan, Xiujuan Xiang, Huang Liao, Huiting Feng, Yussuf Mohamed Salum, Minsheng You, Wei Chen, Weiyi He
    Journal of Integrative Agriculture. 2024, 23(9): 3089-3103. https://doi.org/10.1016/j.jia.2024.04.029
    Genetic pest control strategies based on precise sex separation and only releasing sterile males can be accomplished by site-specific genome editing.  In the current study, we showed that the mutation of single-allele Pxfl(2)d can significantly impair the normal mating behavior and testis development in male adults of the notorious cruciferous insect pest Plutella xylostella, in addition to its known functions in the ovarian development in female adults and egg hatching.  Subsequent CRISPR/Cas9-based knock-in experiments revealed that site-specific integration of an exogenous green fluorescent protein (GFP) gene into autosomal Pxfl(2)d for labelling mutants could be achieved.  However, this gene is not a suitable target for GFP insertion to establish a genetically stable knock-in strain because of the severe decline in reproductive capacity.  We further screened for the W-chromosome-linked and Z-chromosome-linked regions to test the knock-in efficiency mediated by CRISPR/Cas9.  The results verified that both types of chromosomes can be targeted for the site-specific insertion of exogenous sequences.  We ultimately obtained a homozygous knock-in strain with the integration of both Cas9 and cyan fluorescent protein (CFP) expression cassettes on a Z-linked region in Pxylostella, which can also be used for early sex detection.  By injecting the sgRNA targeting Pxfl(2)d alone into the eggs laid by female adults of the Z-Cas9-CFP strain, the gene editing efficiency reached 29.73%, confirming the success of expressing a functional Cas9 gene.  Taken together, we demonstrated the feasibility of the knock-in of an exogenous gene to different genomic regions in Pxylostella, while the establishment of a heritable strain required the positioning of appropriate sites.  This study provides an important working basis and technical support for further developing genetic strategies for insect pest control.


  • Plant Protection
    Jianqiang Bao, Yuxuan Chen, Suwan Jiang, Rui Liu, Xi Zhang, Fangzheng Zhang, Zhiwei Chen, Chen Luo, Hailong Kong
    Journal of Integrative Agriculture. 2024, 23(9): 3078-3088. https://doi.org/10.1016/j.jia.2024.01.024
    It has been reported that C-type lectins (CTLs), which are pattern recognition receptors of the insect innate immunity response, may compete with Cry toxin for the receptor alkaline phosphatase to decrease its toxicity in insects.  However, to date, which CTLs affect larval susceptibility to Bt in Spodoptera exigua is not clear.  In this study, 33 CTL genes were identified from Sexigua.  Based on the number of carbohydrate-recognition domains (CRDs) and the domain architectures, they were classified into three groups: (1) nineteen CTL-S (single-CRD), (2) eight immulectin (dual-CRD) and (3) six CTL-X (CRD with other domains).  RT-qPCR analysis revealed that expression levels of SeCTL-S15, IML-4 and CTL-X6 were upregulated after challenge with Bt and Cry1Ab.  Tissue and developmental stage expression analysis showed that only SeCTL-S15 was mainly expressed in the midgut and larva, respectively.  Knockdown of SeCTL-S15 significantly increased Bt susceptibility, as indicated by reduced survival and larval weight.  These results suggest that CTL-S15 might play a vital role in the low susceptibility of larvae to Bt in Sexigua.  Our results provide new insights into CTL function in insects.


  • Plant Protection
    Mingming Yang, Yunxiao Tan, Jiabing Ma, Yingjia Zhao, Xia Yan, Nana Wang, Pingping Wang, Jiaqi Tan, Suilong Ai, Xiaofei Liang, Bangshuai Chang, Obadah E. A. Yousif, Chao Zhao, Bo Wang, Guoliang Qian, Lili Huang
    Journal of Integrative Agriculture. 2024, 23(9): 3066-3077. https://doi.org/10.1016/j.jia.2023.11.047
    Bacterial species of the genus Lysobacter are environmentally ubiquitous with strong antifungal biocontrol potential.  Heat-stable antifungal factor (HSAF) secreted by the biocontrol bacterium Lysobacter enzymogenes OH11 has broad-spectrum and highly efficient antifungal activity.  Studying the biosynthetic regulations of HSAF would lay an important foundation for strain engineering toward improved HSAF production.  In this work, we demonstrate that Le0752, an orotidine-5´-phosphate decarboxylase enzyme (ODCase) catalyzing a pivotal step of the UMP de novo biosynthesis pathway, is vital for HSAF-mediated antimicrobial activities and growth of Lenzymogenes OH11, but not for twitching motility.  This gene regulates the production of HSAF by affecting the expression of lafB, a key gene in the HSAF biosynthesis operon, through the transcription factor Clp.  Interestingly, bioinformatics analysis revealed that Le0752 belongs to the Group III ODCases, whereas its homologs in the closely related genera Xanthomonas and Stenotrophomonas belong to Group I, which contains most ODCases from Gram-positive bacteria, Gram-negative bacteria and cyanobacteria.  Moreover, the Group I ODCase PXO_3614 from the Xanthomonas oryzae pv.  oryzae PXO99A strain complemented the Le0752 mutant in regulating HSAF-mediated antagonistic activity.  Together, these results highlight the important requirement of de novo pyrimidine biosynthetic enzymes for antibiotic HSAF production in Lenzymogenes, which lays an important foundation for improving HSAF production via metabolic flow design and for dissecting the regulatory functions of bacterial ODCases.
  • Plant Protection
    Haiyang Li, Yuan Zhang, Cancan Qin, Zhifang Wang, Lingjun Hao, Panpan Zhang, Yongqiang Yuan, Chaopu Ding, Mengxuan Wang, Feifei Zan, Jiaxing Meng, Xunyu Zhuang, Zheran Liu, Limin Wang, Haifeng Zhou, Linlin Chen, Min Wang, Xiaoping Xing, Hongxia Yuan, Honglian Li, Shengli Ding
    Journal of Integrative Agriculture. 2024, 23(9): 3055-3065. https://doi.org/10.1016/j.jia.2024.01.001
    Fusarium pseudograminearum is a devastating pathogen that causes Fusarium crown rot (FCR) in wheat and poses a significant threat to wheat production in terms of grain yield and quality.  However, the mechanism by which Fpseudograminearum infects wheat remains unclear.  In this study, we aimed to elucidate these mechanisms by constructing a T-DNA insertion mutant library for the highly virulent strain WZ-8A of Fpseudograminearum.  By screening this mutant library, we identified nine independent mutants that displayed impaired pathogenesis in barley leaves.  Among these mutants, one possessed a disruption in the gene FpRCO1 that is an ortholog of Saccharomyces cerevisiae RCO1, encoding essential component of the Rpd3S histone deacetylase complex in F. pseudograminearum.  To further investigate the role of FpRCO1 in Fpseudograminearum, we employed a split-marker approach to knock out FpRCO1 in Fpseudograminearum WZ-8A.  FpRCO1 deletion mutants exhibit reduced vegetative growth, conidium production, and virulence in wheat coleoptiles and barley leaves, whereas the complementary strain restores these phenotypes.  Moreover, under stress conditions, the FpRCO1 deletion mutants exhibited increased sensitivity to NaCl, sorbitol, and SDS, but possessed reduced sensitivity to H2O2 compared to these characteristics in the wild-type strain.  RNA-seq analysis revealed that deletion of FpRCO1 affected gene expression (particularly the downregulation of TRI gene expression), thus resulting in significantly reduced deoxynivalenol (DON) production.  In summary, our findings highlight the pivotal role of FpRCO1 in regulating vegetative growth and development, asexual reproduction, DON production, and pathogenicity of Fpseudograminearum.  This study provides valuable insights into the molecular mechanisms underlying Fpseudograminearum infection in wheat and may pave the way for the development of novel strategies to combat this devastating disease.


  • Plant Protection
    Tong Shen, Mengdi Ye, Yeping Xu, Bohan Ding, Hongtao Li, Li Zhang, Jun Wang, Yanli Tian, Baishi Hu, Youfu Zhao
    Journal of Integrative Agriculture. 2024, 23(9): 3045-3054. https://doi.org/10.1016/j.jia.2024.05.020
    Bacterial–fungal interactions are widespread in nature.  We observed that pear orchards affected by Cytospora pyri (formerly Valsa pyri) were often accompanied with Erwinia amylovora.  However, the relationship of the two pathogens was unclear.  The objective of this study was to determine whether the synergistic effect exists between Eamylovora and Cpyri.  We first analyzed the coexistence frequencies of Eamylovora and Cpyri in pear trees.  Virulence of the two pathogens, growth, physical interactions, amylovoran production, and expression of genes for amylovoran biosynthesis were conducted.  Our results showed that Eamylovora and Cpyri could coexist on the same lesion and caused much more severe disease.  We also found that Eamylovora could physically attach to Cpyri and the expression of amylovoran biosynthesis genes were up-regulated with fungal metabolite treatment.  These results indicate that Eamylovora and Cpyri can cooperatively interact, which provides Cpyri with an opportunity to promote bacterial dispersal and production of virulence factor in Eamylovora.


  • Horticulture
    Peihua Du, Yang Cao, Huaite Liu, Jiahao Ji, Wei Sun, Xueying Zhang, Jizhong Xu, Bowen Liang
    Journal of Integrative Agriculture. 2024, 23(9): 3025-3044. https://doi.org/10.1016/j.jia.2024.07.011
    Apple replant disease (ARD) is a complex agricultural problem caused by multiple stressors that can lead to increased reactive oxygen species (ROS) levels and limited nutrient utilization in plants.  However, existing countermeasures cannot effectively address this challenge.  Here, we used Malus hupehensis as a test organism to investigate whether the pleiotropic molecule dopamine can alleviate ARD using pot experiments.  Exogenous application of 100 μmol L–1 dopamine significantly promoted the growth of apple seedlings in the replanted soil, with a relative growth rate increase of 17.44%.  Our results revealed two major pathways by which dopamine regulates ARD resistance in apple trees.  First, dopamine effectively reduces the level of ROS and activates the expression of genes related to nitrogen (N) transport and metabolism.  Among those genes, MdNLP5, MdNRT1.1, MdNLP2, MdNRT2.5, MdNLP3, MdNRT2.4, MdNADH-GAGOT, and MdFd-GAGOT were strongly regulated by dopamine.  These regulatory effects promoted the uptake and utilization of soil N by the plants.  Second, dopamine improved the physical and chemical properties, enhanced microbial community diversity, and promoted mutual cooperation between microbial communities in the soil.  Furthermore, dopamine altered the microbial structure of rhizosphere soil (upregulating Clostridiales, Gaiellales, Sordariales and Mortierellales; downregulating Micrococcales, Longimicrobiales, Hypocreales and Cystobasidiales).  Notably, dopamine significantly upregulated the abundances of Gaiella and Mortierella, both of which were positively correlated with soil urease activity, soil available N content, plant growth and N uptake.  Dopamine also significantly downregulated the abundance of the plant pathogen Gibberella (by 11.71-fold) in replant soil.  Our results provide insights into the mechanisms by which dopamine promotes ARD resistance, and can promote the sustainable development of the apple industry.


  • Horticulture
    Qianwei Liu, Shuo Xu, Lu Jin, Xi Yu, Chao Yang, Xiaomin Liu, Zhijun Zhang, Yusong Liu, Chao Li, Fengwang Ma
    Journal of Integrative Agriculture. 2024, 23(9): 3012-3024. https://doi.org/10.1016/j.jia.2024.03.003
    Apple replant disease (ARD) has led to severe yield and quality reduction in the apple industry.  Fusarium solani (Fsolani) has been identified as one of the main microbial pathogens responsible for ARD.  Auxin (indole-3-acetic acid, IAA), an endogenous hormone in plants, is involved in almost all plant growth and development processes and plays a role in plant immunity against pathogens.  Gretchen Hagen3 (GH3) is one of the early/primary auxin response genes.  The aim of this study was to evaluate the function of MdGH3-2 and MdGH3-12 in the defense response of Fsolani by treating MdGH3-2/12 RNAi plants with Fsolani.  The results show that under Fsolani infection, RNAi of MdGH3-2/12 inhibited plant biomass accumulation and exacerbated root damage.  After inoculation with Fsolani, MdGH3-2/12 RNAi inhibited the biosynthesis of acid-amido synthetase.  This led to the inhibition of free IAA combining with amino acids, resulting in excessive free IAA accumulation.  This excessive free IAA altered plant tissue structure, accelerated fungal hyphal invasion, reduced the activity of antioxidant enzymes (SOD, POD and CAT), increased the reactive oxygen species (ROS) level, and reduced total chlorophyll content and photosynthetic ability, while regulating the expression of PR-related genes including PR1, PR4, PR5 and PR8.  It also changed the contents of plant hormones and amino acids, and ultimately reduced the resistance to Fsolani.  In conclusion, these results demonstrate that MdGH3-2 and MdGH3-12 play an important role in apple tolerance to Fsolani and ARD.


  • Horticulture
    Guoling Guo, Haiyan Zhang, Weiyu Dong, Bo Xu, Youyu Wang, Qingchen Zhao, Lun Liu, Xiaomei Tang, Li Liu, Zhenfeng Ye, Wei Heng, Liwu Zhu, Bing Jia
    Journal of Integrative Agriculture. 2024, 23(9): 2989-3011. https://doi.org/10.1016/j.jia.2024.01.012
    Drought stress is a devastating natural disaster driven by the continuing intensification of global warming, which seriously threatens the productivity and quality of several horticultural crops, including pear.  Gibberellins (GAs) play crucial roles in plant growth, development, and responses to drought stress.  Previous studies have shown significant reductions of GA levels in plants under drought stress; however, our understanding of the intrinsic regulation mechanisms of GA-mediated drought stress in pear remains very limited.  Here, we show that drought stress can impair the accumulation of bioactive GAs (BGAs), and subsequently identified PbrGA2ox1 as a chloroplast-localized GA deactivation gene.  This gene was significantly induced by drought stress and abscisic acid (ABA) treatment, but was suppressed by GA3 treatment.  PbrGA2ox1-overexpressing transgenic tobacco plants (Nicotiana benthamiana) exhibited enhanced tolerance to dehydration and drought stresses, whereas knock-down of PbrGA2ox1 in pear (Pyrus betulaefolia) by virus-induced gene silencing led to elevated drought sensitivity.  Transgenic plants were hypersensitive to ABA, and had a lower BGAs content, enhanced reactive oxygen species (ROS) scavenging ability, and augmented ABA accumulation and signaling under drought stress compared to wild-type plants.  However, the opposite effects were observed with PbrGA2ox1 silencing in pear.  Moreover, exogenous GA3 treatment aggravated the ROS toxic effect and restrained ABA synthesis and signaling, resulting in the compromised drought tolerance of pear.  In summary, our results shed light on the mechanism by which BGAs are eliminated in pear leaves under drought stress, providing further insights into the mechanism regulating the effects of GA on the drought tolerance of plants.


  • Crop Science
    Xinrui Li, Xiafei Li, Tao Liu, Huilai Yin, Hao Fu, Yongheng Luo, Yanfu Bai, Hongkun Yang, Zhiyuan Yang, Yongjian Sun, Jun Ma, Zongkui Chen
    Journal of Integrative Agriculture. 2024, 23(9): 2970-2988. https://doi.org/10.1016/j.jia.2023.10.005
    Rice‒rape, rice‒wheat and rice‒garlic rotations are common cropping systems in Southwest China, and they have played a significant role in ensuring ecological and economic benefits (EB) and addressing the challenges of China’s food security in the region.  However, the crop yields in these rotation systems are 1.25‒14.73% lower in this region than the national averages.  Intelligent decision-making with machine learning can analyze the key factors for obtaining better benefits, but it has rarely been used to enhance the probability of obtaining such benefits from rotations in Southwest China.  Thus, we used a data-intensive approach to construct an intelligent decision‒making system with machine learning to provide strategies for improving the benefits of rice–rape, rice–wheat, and rice–garlic rotations in Southwest China.  The results show that raising the yield and partial fertilizer productivity (PFP) by increasing seed input under high fertilizer application provided the optimal benefits with a 10% probability in the rice–garlic system.  Obtaining high yields and greenhouse gas (GHG) emissions by increasing the N application and reducing the K application provided suboptimal benefits with an 8% probability in the rice–rape system.  Reducing N and P to enhance PFP and yield provided optimal benefits with the lowest probability (8%) in the rice‒wheat system.  Based on the predictive analysis of a random forest model, the optimal benefits were obtained with fertilization regimes by reducing N by 25% and increasing P and K by 8 and 74%, respectively, in the rice–garlic system,  reducing N and K by 54 and by 36%, respectively, and increasing P by 38% in rice–rape system, and reducing N by 4% and increasing P and K by 65 and 23% in rice–wheat system.  These strategies could be further optimized by 17‒34% for different benefits, and all of these measures can improve the effectiveness of the crop rotation systems to varying degrees.  Overall, these findings provide insights into optimal agricultural inputs for higher benefits through an intelligent decision-making system with machine learning analysis in the rice–rape, rice‒wheat, and rice–garlic systems.
  • Crop Science
    Xin Dong, Baole Li, Zhenzhen Yan, Ling Guan, Shoubing Huang , Shujun Li, Zhiyun Qi, Ling Tang, Honglin Tian, Zhongjun Fu, Hua Yang
    Journal of Integrative Agriculture. 2024, 23(9): 2955-2969. https://doi.org/10.1016/j.jia.2023.09.007

    Heat stress is a major constraint to current and future maize production at the global scale.  Male and female reproductive organs both play major roles in increasing seed set under heat stress at flowering, but their relative contributions to seed set are unclear.  In this study, a 2-year field experiment including three sowing dates in each year and 20 inbred lines was conducted.  Seed set, kernel number per ear, and grain yield were all reduced by more than 80% in the third sowing dates compared to the first sowing dates.  Pollen viability, silk emergence ratio, and anthesis–silking interval were the key determinants of seed set under heat stress; and their correlation coefficients were 0.89***, 0.65***, and –0.72***, respectively.  Vapor pressure deficit (VPD) and relative air humidity (RH) both had significant correlations with pollen viability and the silk emergence ratio.  High RH can alleviate the impacts of heat on maize seed set by maintaining high pollen viability and a high silk emergence ratio.  Under a warming climate from 2020 to 2050, VPD will decrease due to the increased RH.  Based on their pollen viability and silk emergence ratios, the 20 genotypes fell into four different groups.  The group with high pollen viability and a high silk emergence ratio performed better under heat stress, and their performance can be further improved by combining the improved flowering pattern traits. 

  • Crop Science
    Qing Liang, Xujing Yang, Yuheng Huang, Zhenwei Yang, Meichen Feng, Mingxing Qing, Chao Wang, Wude Yang, Zhigang Wang, Meijun Zhang, Lujie Xiao, Xiaoyan Song
    Journal of Integrative Agriculture. 2024, 23(9): 2941-2954. https://doi.org/10.1016/j.jia.2024.02.006
    Determining the suitable areas for winter wheat under climate change and assessing the risk of freezing injury are crucial for the cultivation of winter wheat.  We used an optimized Maximum Entropy (MaxEnt) Model to predict the potential distribution of winter wheat in the current period (1970–2020) and the future period (2021–2100) under four shared socioeconomic pathway scenarios (SSPs).  We applied statistical downscaling methods to downscale future climate data, established a scientific and practical freezing injury index (FII) by considering the growth period of winter wheat, and analyzed the characteristics of abrupt changes in winter wheat freezing injury by using the Mann-Kendall (M-K) test.  The results showed that the prediction accuracy AUC value of the MaxEnt Model reached 0.976.  The minimum temperature in the coldest month, precipitation in the wettest season and annual precipitation were the main factors affecting the spatial distribution of winter wheat.  The total suitable area of winter wheat was approximately 4.40×107 ha in the current period.  In the 2070s, the moderately suitable areas had the greatest increase by 9.02×105 ha under SSP245 and the least increase by 6.53×105 ha under SSP370.  The centroid coordinates of the total suitable areas tended to move northward.  The potential risks of freezing injury in the high-latitude and -altitude areas of the Loess Plateau, China increased significantly.  The northern areas of Xinzhou in Shanxi Province, China suffered the most serious freezing injury, and the southern areas of the Loess Plateau suffered the least.  Environmental factors such as temperature, precipitation and geographical location had important impacts on the suitable area distribution and freezing injury risk of winter wheat.  In the future, greater attention should be paid to the northward boundaries of both the winter wheat planting areas and the areas of freezing injury risk to provide the early warning of freezing injury and implement corresponding management strategies.


  • Crop Science
    Zhenxiang Zhou, Paul C. Struik, Junfei Gu, Peter E. L. van der Putten, Zhiqin Wang, Jianchang Yang, Xinyou Yin
    Journal of Integrative Agriculture. 2024, 23(9): 2923-2940. https://doi.org/10.1016/j.jia.2024.03.034
    Leaf-color modification can affect canopy photosynthesis, with potential effects on rice yield and yield components.  Modulating source–sink relationships through crop management is often used to improve crop productivity.  This study investigated whether and how modifying leaf color alters source–sink relationships and whether current crop cultivation practices remain applicable for leaf-color modified genotypes.  Periodically collected data of total biomass and nitrogen (N) accumulation in rice genotypes of four genetic backgrounds and their leaf-color modified variants (greener or yellower) were analyzed, using a recently established modelling method to quantify the source–sink (im)balance during grain filling.  Among all leaf-color variants, only one yellower-leaf variant showed a higher source capacity than its normal genotype.  This was associated with greater post-flowering N-uptake that prolonged the functional leaf-N duration, and this greater post-flowering N-uptake was possible because of reduced pre-flowering N-uptake.  A density experiment showed that current management practices (insufficient planting density accompanied by abundant N application) are unsuitable for the yellower-leaf genotype, ultimately limiting its yield potential.  Leaf-color modification affects source–sink relationships by regulating the N trade-off between pre-and post-flowering uptake, as well as N translocation between source and sink organs.  To best exploit leaf-color modification for improving crop productivity, adjustments of crop management practices are required.  
  • Crop Science
    Mingming Wang, Jia Geng, Zhe Zhang, Zihan Zhang, Lingfeng Miao, Tian Ma, Jiewen Xing, Baoyun Li, Qixin Sun, Yufeng Zhang, Zhongfu Ni
    Journal of Integrative Agriculture. 2024, 23(9): 2911-2922. https://doi.org/10.1016/j.jia.2023.09.009
    Grain size is one of the determinants of grain yield, and identifying the genetic loci that control grain size will be helpful for increasing grain yield. In our previous study, a quantitative trait locus (QTL) for grain length (GL), QGl.cau-2D.1, was identified from an F2 population developed from the cross between the natural (TAA10) and synthetic (XX329) allohexaploid wheat. In the present study, we mainly fine mapped and validated its genetic effects. To this end, multiple near-isogenic lines (NILs) were obtained through marker-assisted selection with TAA10 as the recurrent parent. The secondary populations derived from 25 heterozygous recombinants were used for fine mapping of QGl.cau-2D.1, and the allele from XX329 significantly increased GL, thousand-grain weight (TGW), total spikelet number per spike (TSN) and spike compactness (SC). Using NILs for XX329 (2D+) and TAA10 (2D−), we determined the genetic and pleiotropic effects of QGl.cau-2D.1. The target sequences were aligned with the wheat reference genome RefSeq v2.1 and spanned an ~0.9 Mb genomic region. TraesCS2D03G0114900 (ortholog of Os03g0594700) was predicted as the candidate gene based on whole-genome re-sequencing and expression analyses. In summary, the map-based cloning of QGl.cau-2D.1 will be useful for improving grain weight with enhanced GL and TSN.
  • Crop Science
    Chengwei Huang, Zhijuan Ji, Qianqian Huang, Liling Peng, Wenwen Li, Dandan Wang, Zepeng Wu, Jia Zhao, Yongqi He, Zhoufei Wang
    Journal of Integrative Agriculture. 2024, 23(9): 2898-2910. https://doi.org/10.1016/j.jia.2023.06.018
    Seed vigor is a crucial trait for the direct seeding of rice.  Here we examined the genetic regulation of seed vigor traits in rice, including germination index (GI) and germination potential (GP), using a genome-wide association study approach.  One major quantitative trait locus, qGI6/qGP6, was identified simultaneously for both GI and GP.  The candidate gene encoding the cytochrome c oxidase subunit 5B (OsCOX5B) was validated for qGI6/qGP6.  The disruption of OsCOX5B caused the vigor traits to be significantly lower in Oscox5b mutants than in the japonica Nipponbare wild type (WT).  Gene co-expression analysis revealed that OsCOX5B influences seed vigor mainly by modulating the tricarboxylic acid cycle process.  The glucose levels were significantly higher while the pyruvic acid and adenosine triphosphate levels were significantly lower in Oscox5b mutants than in WT during seed germination.  The elite haplotype of OsCOX5B facilitates seed vigor by increasing its expression during seed germination.  Thus, we propose that OsCOX5B is a potential target for the breeding of rice varieties with enhanced seed vigor for direct seeding.


  • Review
    Zhengyuan Xu, Lingzhen Ye, Qiufang Shen, Guoping Zhang
    Journal of Integrative Agriculture. 2024, 23(9): 2877-2897. https://doi.org/10.1016/j.jia.2023.12.028
    Waterlogging is one of the major abiotic stresses threatening crop yields globally.  Under waterlogging stress, plants suffer from oxidative stress, heavy metal toxicity and energy deficiency, leading to metabolic disorders and growth inhibition.  On the other hand, plants have evolved waterlogging-tolerance or adaptive mechanisms, including morphological changes, alternation of respiratory pathways, antioxidant protection and endogenous hormonal regulation.  In this review, recent advances in studies on the effects of waterlogging stress and the mechanisms of waterlogging tolerance in plants are presented, and the genetic differences in waterlogging tolerance among plant species or genotypes within a species are illustrated.  We also summarize the identified QTLs and key genes associated with waterlogging tolerance.  
  • TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY
    ZANGShaoLong, LIULinRu, GAOYueZhi, WUKe, HELi, DUANJianZhao, SONGXiao, FENGWei
    Scientia Agricultura Sinica. 2024, 57(9): 1687-1708. https://doi.org/10.3864/j.issn.0578-1752.2024.09.006

    【Objective】To explore the potential of UAV remote sensing in nitrogen efficiency classification and recognition, a nitrogen efficiency classification method for wheat varieties was constructed, so as to provide the theoretical basis and technical support for nitrogen efficient variety screening.【Method】Six agronomic indicators related to nitrogen efficiency at maturity stage (yield, plant nitrogen accumulation, nitrogen physiological use efficiency, plant dry biomass, total nitrogen uptake of grains, and N harvest index) were used to construct the principal component synthesis value, and K-Means cluster analysis was performed on them. The 121 wheat varieties were divided into three types: high, medium, and low nitrogen efficiency types. A UAV remote sensing platform equipped with a multi-spectral camera was used to obtain remote sensing images of wheat at the jointing, booting and flowering stages, and 34 vegetation indices were extracted to analyze the correlation between vegetation index and nitrogen efficiency comprehensive value. The accuracy of nitrogen efficiency classification models of support vector machine (SVM), random forest (RF), and K-nearest neighbor (KNN) classification methods were compared, and the overall classification accuracy (OA) and Kappa coefficient were used to compare the classification and recognition ability of wheat varieties in different growth periods. Three different feature set screening methods(ReliefF algorithm, Boruta algorithm and RF-RFE algorithm) were used to comprehensively evaluate the optimized feature subsets, and an appropriate classification and recognition method for wheat varieties nitrogen efficiency was established.【Result】With the progress of wheat growth stage, the correlation between vegetation index and the comprehensive value of nitrogen efficiency gradually increased, which reached the highest correlation coefficient at flowering stage (r=0.502). The full feature set of vegetation indices was used to classify the nitrogen efficiency of wheat varieties. For the data of single growth stage, SVM model had the best classification accuracy at flowering stage (OA=77.1%, Kappa=0.591), and the worst classification accuracy at jointing stage (OA=65.6%, Kappa=0.406). In general, the classification accuracy of nitrogen efficiency of varieties with multi-growth stage data fusion was higher than that of single growth stage, among which SVM model with jointing stage + booting stage + flowering stage had the best classification accuracy (OA=80.6%, Kappa=0.669). In order to reduce the number of feature set variables in multi-growth period data fusion, the feature optimization effects of RF-RFE, Boruta and ReliefF algorithms were compared and analyzed. The optimal feature subset based on RF-RFE algorithm had the highest classification accuracy, and its OA and Kappa coefficients were 4.0% and 10.1% higher than those of the full feature set classification model, respectively. Among them, the data fusion of three growth stages had the best classification accuracy (OA=85.4%, Kappa=0.749).【Conclusion】The nitrogen efficiency evaluation method with six nitrogen efficiency indexes - principal component analysis -K-Means were established in this study. The RF-RFE algorithm effectively optimized the number of characteristic subsets of the multi-growth period combination, and obtained high classification accuracy. A nitrogen efficiency classification model of wheat varieties based on the fusion of multi-growth period combination and RF-RFE-SVM technology was established, which provided the theoretical basis and technical support for the rapid and accurate classification and identification of wheat varieties with nitrogen efficiency.

  • SPECIAL FOCUS: DROUGHT RESISTANCE IDENTIFICATION AND GENETIC RESOURCE MINING IN WHEAT
    YANWen, JINXiuLiang, LILong, XUZiHan, SUYue, ZHANGYueQiang, JINGRuiLian, MAOXinGuo, SUNDaiZhen
    Scientia Agricultura Sinica. 2024, 57(9): 1674-1686. https://doi.org/10.3864/j.issn.0578-1752.2024.09.005

    【Objective】To evaluate the drought resistance of synthetic wheat germplasm based on multi-source images collected by unmanned aerial vehicle (UAV) and yield data, explore high-throughput indices for drought resistance evaluation, and identify synthetic wheat germplasm resources with drought resistance. This provides technical support and germplasm materials for accelerating the expansion of drought-resistant genetic resources for wheat and enhancing the level of breeding for dryland wheat.【Method】Eighty synthetic wheat germplasm and the control variety Xin Chun 37 were used as plant materials, which were sown in the field and treated with a water regime of drought stress and irrigation. Multi-source images of test materials during filling stage were collected by multi-spectral and thermal infrared cameras equipped with unmanned aerial vehicle, and the spectral index of each test material was extracted by threshold segmentation. The analyses of Pearson’s correlation and principal component were performed to identify drought resistance-related spectral indices, and the drought resistance of each synthetic wheat germplasm was determined by single index and comprehensive evaluation methods. 【Result】The drought resistance coefficients of 19 spectral indices of 80 synthetic wheat germplasm were calculated based on multisource imagery data obtained from unmanned aerial vehicles. The correlation analysis between the spectral indices and the yield-based drought index (DRI) showed that among the drought resistance coefficients of the 19 spectral indices, OSAVI exhibited the highest correlation with the drought index, while NDVI, CIre, and NDRE demonstrated relatively strong associations with the drought index. However, the different drought indices showed a high correlation, resulting in redundant information. The drought resistance coefficients of the 19 spectral indices were transformed into three independent comprehensive indicators through principal component analysis, with contribution rates of 59.6%, 12.0% and 9.6%, respectively. The comprehensive drought resistance index (D) for each synthetic wheat germplasm were calculated by aggregating the three independent comprehensive indicators using the weighted membership function method. 6 and 5 synthetic wheat germplasms with strong drought resistance were identified based on DRI and D, respectively. Among them, 2 germplasms (SW004 and SW009) with high drought resistance were detected based on both DRI and D. Furthermore, the drought resistance of the 80 synthetic wheat germplasms was graded based on the drought resistance coefficient of OSAVI, and the grading results were found to be consistent with that based on the D value. Among the six strongly drought-resistant germplasms identified based on the drought resistance coefficient of OSAVI, five of them were also classified as strongly drought-resistant germplasms based on comprehensive drought resistance evaluation.【Conclusion】The spectral indices NDVI, OSAVI, CIre and NDRE extracted from UAV-based multi-source images, as well as the drought resistance comprehensive evaluation value can be used to assist in the identification of drought resistance of wheat germplasm.

  • SPECIAL FOCUS: DROUGHT RESISTANCE IDENTIFICATION AND GENETIC RESOURCE MINING IN WHEAT
    ZHANGYing, SHITingRui, CAORui, PANWenQiu, SONGWeiNing, WANGLi, NIEXiaoJun
    Scientia Agricultura Sinica. 2024, 57(9): 1658-1673. https://doi.org/10.3864/j.issn.0578-1752.2024.09.004

    【Objective】Drought is one of the most destructive environmental stresses limiting wheat production. The novel germplasm with excellent drought tolerance as well as their candidate loci were identified and characterized to enrich the genetic basis of drought tolerance and lay a material foundation for wheat genetic improvement in China. 【Method】In this study, the drought tolerance of 198 wheat accessions introduced from International Dry Area Agriculture Research (ICARDA) were investigated at seedling stage through hydroponic method with PEG6000 simulating drought. Drought tolerance index (DTI) was calculated using the shoot fresh weight, root fresh weight, total biomass and root-shoot ratio, respectively. Genome-wide association analysis was performed using 660K SNP array genotyping to obtain the SNP loci and chromosome regions associating with drought tolerance index. Combined with the expression patterns in root and other tissues, the potential candidate genes were identified, and then they were further verified by qRT-PCR approach with the most drought-tolerant accession IR214 and the most drought-sensitive accession IR36 as materials. Finally, the excellent haplotypes of key candidate genes were analyzed. 【Result】Compared to normal control condition, the growth and development of wheat were significantly impaired under drought treatment. There were also significant phenotypic variations among different accessions with all of the four traits displayed normal distribution. The coefficient of variation ranged from 0.363 to 0.760 with genetic diversity from 0.310 to 0.400. Using the weighted membership function value (D value), the drought tolerance of these accessions was evaluated. Results showed that accession IR214 had the highest D value with 0.851, followed by IR92, IR213, IR235, and IR218, which could be considered as the novel excellent drought-tolerance germplasm. Furthermore, through genome-wide association study (GWAS) analysis, a total of 102 loci were significantly associated with the DTI values based on these four traits, with the phenotypic variation explained value (PVE) from 1.07% to 38.70%, of which 60 loci were associated with above-ground fresh weight, 1 locus associated with underground fresh weight, 36 loci associated with biomass and the remaining 5 loci associated with root-shoot ratio. Then, 31 candidate genes were predicated based on genomic annotation information and LD block. Combined with the expression patterns of them in roots and other tissues, 4 candidates displaying differential expression between CK and drought conditions were obtained. Finally, the expression levels of these 4 candidates were further verified by qRT-PCR method with the most drought- tolerant accession IR214 and the most drought-sensitive accession IR36 as materials to obtain two key candidates associating with drought tolerance. Additionally, their haplotype effects were investigated. It was found that the different genotypes of AX-86174509 locus in TraesCS6A02G048600 gene showed significant differences in drought tolerance, which might be considered as a causal locus.【Conclusion】Totally, 102 loci and 2 key candidate genes (TraesCS5B02G053500 and TraesCS6A02G048600) underlying drought tolerance at seedling stage were detected in ICARDA-introduced wheat, and AX-86174509 in TraesCS6A02G048600 was a potential functional locus.

  • SPECIAL FOCUS: DROUGHT RESISTANCE IDENTIFICATION AND GENETIC RESOURCE MINING IN WHEAT
    ZHOUQuan, LUQiuMei, ZHAOZhangChen, WUChenRan, FUXiaoGe, ZHAOYuJiao, HANYong, LINHuaiLong, CHENWeiLin, MOULiMing, LIXingMao, WANGChangHai, HUYinGang, CHENLiang
    Scientia Agricultura Sinica. 2024, 57(9): 1646-1657. https://doi.org/10.3864/j.issn.0578-1752.2024.09.003

    【Objective】Drought is a major environmental factor limiting global wheat production, and breeding drought-tolerant varieties is a key challenge faced by wheat breeders worldwide. Spring wheat, which has a short growth period, plays a vital role for national food security and planting structure, therefore, it is of great importance to identify and select drought tolerance of spring wheat varieties for breeding of high-yielding and drought-tolerant wheat.【Method】In this study, 244 spring wheat varieties (lines) from 10 different regions were used to assess the drought tolerance of spring wheat varieties during the seedling stage, this study used the controlled water content method to impose drought stress during the seedling stage, 5 seedlings with uniform and consistent growth were selected during the trefoil stage. Thirteen seedling stage indicators including maximum root length (MRL), first leaf length (FLL), first leaf width (FLW), coleoptile length (CL), shoot fresh weight (SFW) and root fresh weight (RFW) were measured. Comprehensive evaluation of drought resistance of various spring wheat varieties (lines) was conducted through methods such as using descriptive statistics, membership function, principal component analysis, cluster analysis, and correlation analysis. 【Result】The drought tolerance of spring wheat varieties (lines) exhibits a large variation. The coefficient of variation of the measured traits under drought treatment conditions ranges from 2.1% to 32.9%, while the coefficient of variation of the control group ranges from 1.0% to 29.3%. Compared with the control, the coleoptile length, root dry weight, fresh weight root to shoot ratio, and dry weight root to shoot ratio under drought treatment were all greater than those under the control treatment. The original 13 indexes were summarized into 5 principal components, and the contribution rate reached 79.56%, and the D value of the comprehensive drought resistance coefficient was calculated according to the characteristic vector of each principal component and the drought resistance coefficient of each trait index, then the D value was clustered and analyzed, which could be divided into 5 subgroups. Therefore, the root biomass (underground fresh weight and dry weight) was screened as an effective comprehensive index for the identification of drought resistance at the seedling stage. We conducted correlation analysis between the seedling stage drought index and the agronomic traits of maturity stage showed that the coleoptile length, first leaf length was significantly positively correlated with flag length, plant height, spike length, the number of spike and grain length. Additionally, and the seedling biomass was significantly positively correlated with thousand-grain weight.【Conclusion】Twenty-two highly drought-tolerant varieties were screened, and root biomass (both fresh and dry weight of the underground part) was identified as an effective comprehensive indicator for evaluating seedling stage drought tolerance.

  • SPECIAL FOCUS: DROUGHT RESISTANCE IDENTIFICATION AND GENETIC RESOURCE MINING IN WHEAT
    ZHANGYuZhou, WANGYiZhao, GAORuXi, LIUYiFan
    Scientia Agricultura Sinica. 2024, 57(9): 1633-1645. https://doi.org/10.3864/j.issn.0578-1752.2024.09.002

    Wheat is the most important cereal crop, and drought is the most significant abiotic stress factor that severely affects wheat growth and development. Plant root system, as a primary organ for crops to acquire water and nutrients, directly determines the efficiency of soil water utilization. In recent years, increasing evidence has shown that plant root system architecture (RSA) plays an important role in plant tolerance to drought stress. This review summarizes the current research progress on the regulation of wheat drought tolerance determined by RSA. First, we present how root tropism especially root gravitropism shapes the RSA, summarize the relevant genes and molecular regulatory mechanism involved in root gravitropic growth, and explain how the root tropism-regulated RSA is implicated in wheat adaptation to drought stress. In addition to root tropic growth, the root development also participates in the RSA formation and the plant adaptability to drought stress. Therefore, this review further summarizes how wheat regulates root development to alter its root system morphology (including increasing root length, modifying lateral root number and root hair density, etc.), thereby enhancing its water acqusition from the soil and its adaption to drought environment. The identified genes involved in wheat root development under drought stress conditions are also systematically summarized. Furthermore, as the underground part of plants, the revelation of RSA has always been a challenging task, which hinders our understanding of the relationship between RSA and plant drought tolerance. Therefore, this review also summarized the available techniques used to analyze the RSA at two- and three-dimension levels. These techniques can measure and analyze wheat root length, density, growth direction, and morphology parameters, laying technical support for an insightful understanding of the relationship between wheat RSA and drought resistance. Finally, we discuss the prospect of the improvement of RSA in breeding wheat drought-resistant varieties, as well as provide an outlook for how to identify genes regulating wheat RSA and pinpoint their regulatory mechanism. In summary, the relationship between wheat RSA and drought resistant is closely associated. The continuous development of sequencing techniques, along with the deepening research on the regulatory mechanism of wheat RSA, will provide new means and strategies for the further breeding of drought-tolerance wheat varieties.

  • SPECIAL FOCUS: DROUGHT RESISTANCE IDENTIFICATION AND GENETIC RESOURCE MINING IN WHEAT
    MAOHuDe, DULinYing, KANGZhenSheng
    Scientia Agricultura Sinica. 2024, 57(9): 1629-1632. https://doi.org/10.3864/j.issn.0578-1752.2024.09.001
  • Research Articles
    ZHANG Hua,LI Na,XING Xinzhu,SHAO Zhenqi,LI Xihuan,ZHANG Caiying
    Chitinase is a kind of glycosyl hydrolases (GH) which hydrolyzes the chitin and other polymers. Chitinase plays an important function in the plant growth and development, as well as in the resistant process to diverse stresses. However, the tissue expression patterns and responses to diverse stresses of chitinase genes in soybean are still unclear, which seriously limited its application in genetic improvement. In this study, the chitinase family genes were identified in the wild soybean (Glycine soja Sieb. and Zucc.) and cultivated soybean (Glycine max(L.)Merr.), and the expression patterns were also analyzed. The results showed that 62 and 55 chitinase genes were identified in the wild soybean and cultivated soybean, which located on 17 and 18 chromosomes, respectively. The phylogenetic tree analysis showed that the chitinase genes were divided into five categories, with Class III and Class V belonging to the GH18 subfamily, while Class I, Class II and Class IV belonging to the GH19 subfamily. Further analysis found many cis-acting elements in the promoter regions of chitinase genes responding to various plant hormones and stresses.Further gene expression analyses in cultivated soybean showed that the chitinase genes presented differential expressions in different tissues and under different stress conditions. Among these genes, Gm.01G142400 and Gm.13G346700 were strongly induced in the leaves of resistant variety after soybean mosaic virus inoculation, Gm.03G254300 and Gm.20G164600 were induced in soybean roots after low phosphorus treatment, and Gm.08G259200 and Gm.19G245400 were induced in soybean nodules under low phosphorus condition. Gene expression analysis in wild soybean showed that the chitinase genes presented differential expressions in different tissues and after salt stress, among which Gs.02G002604 and Gs.02G002940 were highly induced in the leaves of tolerant variety after salt treatment. These results provide important references for further utilizing the chitinase genes in soybean genetic improvement.
  • Research Articles
    WANG Changbiao,YIN Yurong,CHENG Ze,REN Yongkang,NIU Yuqi,LIU Jiang,HAN Bin,YANG Sheng,TANG Chaohui
    The type-B authentic response regulator (B-ARR) family members are positive regulators in cytokinin signal transduction, and play important roles in plant growth and development and resistance to abiotic stresses. However, there are few studies on the B-ARR gene family in wheat. In this study, 25 B-ARR gene family members were identified from wheat genome, and their physicochemical properties, gene structure, cis-acting elements and abiotic stress-induced expression patterns were analyzed by bioinformatics methods. The results showed that all B-ARR proteins were localized in the nucleus based on bioinformatics prediction, and their secondary structure was mainly consisting of α-helix and random crimp. B-ARR genes were not evenly distributed on wheat chromosomes, and the number of B-ARR genes was the highest on chromosome 7. In addition, multiple cis-acting regulatory elements related to growth and development, hormone response, and biological and abiotic stress have been identified in the promoter regions. RT-qPCR analysis showed that the relative expression of TaARRM-like9TaARRM-like10TaARRM-like12 and TaARRM-like13 were significantly up-regulated under abiotic stresses treatments, including drought, salt and low temperature. This study laid a foundation for further research on the role of B-ARR transcription factor in wheat development and abiotic stress response.
  • Research Articles
    GONG Chengru,YUAN Yuhao,LIU Zhen,ZHENG Jizhou,TIAN Zhicheng,LIU Shengli,SHEN Qinghua,HUANG Zhenpu,DONG Chunhao,GAO Yan,LI Qiaoyun,TANG Jianwei,JIAO Zhuqing,YIN Guihong
    This study aims to identify the pre-harvest sprouting resistance in wheat germplasm resources and molecular markers for marker-assisted selection, ultimately obtaining excellent white grain wheat germplasm resources applicable in wheat breeding. These spikes of 222 wheat germplasm resources were tested for pre-harvest sprouting resistance, and the functional markers of eight anti-pre-harvest sprouting genes, including myb10DDFR-BVp1B3PM19-A1MFT-3AMFT-A2MKK3-AQSD1, were used for genotyping. Phenotypic identification results showed that there were significant differences in the relative sprouting percentage of 222 wheat germplasm resources. The relative sprouting percentage ranged from 0 to 1.15, and the average relative sprouting percentage was 0.73. 38 wheat materials were identified to be resistant to pre-harvest sprouting, including 9 white wheat, 27 red wheat and 2 black wheat. Correlation analysis between allele types and relative sprouting percentage showed that the relative sprouting percentage was significantly correlated with functional markers myb10DDFR-BVp1B3MFT-3A and MFT-A2, but not with PM19-A1MKK3-A and QSD1. These results indicated that molecular markers myb10DDFR-BVp1B3MFT-3A and MFT-A2 could be used for detection of pre-harvest sprouting resistance and marker-assisted breeding. Based on the phenotype and genotype results, nine white wheat germplasm resources with pre-harvest sprouting resistance were selected, including Yunong 914, Yunong 946, Fengdecunmai 30, Fangmai 5, Xumai 029, Lianmai 1901, Baofeng 1903, Zhengmai 829 and 13wang27-8, which could be used for genetic breeding and layout of wheat varieties with pre-harvest sprouting resistance.

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