为研究油茶象甲对油茶寄主的选择性趋性，为中国油茶抗虫品种选育提供基础数据。应用野外调查和室内测定相结合的方法，室内测定又分为强迫性和选择性取食、产卵以及嗅觉反应测定的方法，测定油茶象甲成虫对不同油茶树种、品系的取食和产卵选择性。结果发现：油茶象甲对油茶2个树种、3个品系均能造成危害，导致采果前落果的主要原因是由于该虫为害所致；6月份，该虫对其他1个树种、3个品系的取食、产卵趋性均大于广宁红花油茶；该虫在油茶叶片上不产卵，当果皮厚度大于其能蛀入最大值时不产卵；雌成虫出土初期对油茶嫩芽的趋性大于果实和成叶，交配产卵期对油茶果实的趋性大于嫩芽和成叶。

Illumina next generation sequencing (NGS) systems are the major sequencing platform in worldwide next-generation sequencing market. On the other hand, MGI Tech launched a series of new NGS equipment that promises to deliver high-quality sequencing data faster and at lower prices than Illumina's sequencing instruments.In this study, we compared the performance of the two platform's major sequencing instruments-Illumina's NovaSeq 6000 and MGI's MGISEQ-2000 and DNBSEQ-T7-to test whether the MGISEQ-2000 and DNBSEQ-T7 sequencing instruments are also suitable for whole genome sequencing.We sequenced two pairs of normal and tumor tissues from Korean lung cancer patients using the three platforms. Then, we called single nucleotide variants (SNVs) and insertion and deletion (indels) for somatic and germline variants to compare the performance among the three platforms.In quality control analysis, all of the three platforms showed high-quality scores and deep coverages. Comparison among the three platforms revealed that MGISEQ-2000 is most concordant with NovaSeq 6000 for germline SNVs and indels, and DNBSEQ-T7 is most concordant with NovaSeq 6000 for somatic SNVs and indels.These results suggest that the performances of the MGISEQ-2000 and DNBSEQ-T7 platforms are comparable to that of the Illumina NovaSeq 6000 platform and support the potential applicability of the MGISEQ-2000 and DNBSEQ-T7 platforms in actual genome analysis fields.

Analyzing k-mer frequencies in whole-genome sequencing data is becoming a common method for estimating genome size (GS). However, it remains uninvestigated how accurate the method is, especially if it can capture intra-species GS variation.We present findGSE, which fits skew normal distributions to k-mer frequencies to estimate GS. findGSE outperformed existing tools in an extensive simulation study. Estimating GSs of 89 Arabidopsis thaliana accessions, findGSE showed the highest capability in capturing GS variations. In an application with 71 female and 71 male human individuals, findGSE delivered an average of 3039 Mb as haploid human GS, while female genomes were on average 41 Mb larger than male genomes, in astonishing agreement with size difference of the X and Y chromosomes. Further analysis showed that human GS variations link to geographical patterns and significant differences between populations, which can be explained by variable abundances of LINE-1 retrotransposons.R package of findGSE is freely available at https://github.com/schneebergerlab/findGSE and supported on linux and Mac systems.schneeberger@mpipz.mpg.de.Supplementary data are available at Bioinformatics online.© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

GenomeScope is an open-source web tool to rapidly estimate the overall characteristics of a genome, including genome size, heterozygosity rate and repeat content from unprocessed short reads. These features are essential for studying genome evolution, and help to choose parameters for downstream analysis. We demonstrate its accuracy on 324 simulated and 16 real datasets with a wide range in genome sizes, heterozygosity levels and error rates.http://genomescope.org, https://github.com/schatzlab/genomescope.git.mschatz@jhu.edu.Supplementary data are available at Bioinformatics online.© The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

There is a rapidly increasing amount of de novo genome assembly using next-generation sequencing (NGS) short reads; however, several big challenges remain to be overcome in order for this to be efficient and accurate. SOAPdenovo has been successfully applied to assemble many published genomes, but it still needs improvement in continuity, accuracy and coverage, especially in repeat regions.To overcome these challenges, we have developed its successor, SOAPdenovo2, which has the advantage of a new algorithm design that reduces memory consumption in graph construction, resolves more repeat regions in contig assembly, increases coverage and length in scaffold construction, improves gap closing, and optimizes for large genome.Benchmark using the Assemblathon1 and GAGE datasets showed that SOAPdenovo2 greatly surpasses its predecessor SOAPdenovo and is competitive to other assemblers on both assembly length and accuracy. We also provide an updated assembly version of the 2008 Asian (YH) genome using SOAPdenovo2. Here, the contig and scaffold N50 of the YH genome were ~20.9 kbp and ~22 Mbp, respectively, which is 3-fold and 50-fold longer than the first published version. The genome coverage increased from 81.16% to 93.91%, and memory consumption was ~2/3 lower during the point of largest memory consumption.

How genetic information is modified to generate phenotypic variation within a species is one of the central questions in evolutionary biology. Here we focus on the striking intraspecific diversity of >200 aposematic elytral (forewing) colour patterns of the multicoloured Asian ladybird beetle, Harmonia axyridis, which is regulated by a tightly linked genetic locus h. Our loss-of-function analyses, genetic association studies, de novo genome assemblies, and gene expression data reveal that the GATA transcription factor gene pannier is the major regulatory gene located at the h locus, and suggest that repeated inversions and cis-regulatory modifications at pannier led to the expansion of colour pattern variation in H. axyridis. Moreover, we show that the colour-patterning function of pannier is conserved in the seven-spotted ladybird beetle, Coccinella septempunctata, suggesting that H. axyridis' extraordinary intraspecific variation may have arisen from ancient modifications in conserved elytral colour-patterning mechanisms in ladybird beetles.

Relatively little is known about the genomic basis and evolution of wood-feeding in beetles. We undertook genome sequencing and annotation, gene expression assays, studies of plant cell wall degrading enzymes, and other functional and comparative studies of the Asian longhorned beetle, Anoplophora glabripennis, a globally significant invasive species capable of inflicting severe feeding damage on many important tree species. Complementary studies of genes encoding enzymes involved in digestion of woody plant tissues or detoxification of plant allelochemicals were undertaken with the genomes of 14 additional insects, including the newly sequenced emerald ash borer and bull-headed dung beetle.The Asian longhorned beetle genome encodes a uniquely diverse arsenal of enzymes that can degrade the main polysaccharide networks in plant cell walls, detoxify plant allelochemicals, and otherwise facilitate feeding on woody plants. It has the metabolic plasticity needed to feed on diverse plant species, contributing to its highly invasive nature. Large expansions of chemosensory genes involved in the reception of pheromones and plant kairomones are consistent with the complexity of chemical cues it uses to find host plants and mates.Amplification and functional divergence of genes associated with specialized feeding on plants, including genes originally obtained via horizontal gene transfer from fungi and bacteria, contributed to the addition, expansion, and enhancement of the metabolic repertoire of the Asian longhorned beetle, certain other phytophagous beetles, and to a lesser degree, other phytophagous insects. Our results thus begin to establish a genomic basis for the evolutionary success of beetles on plants.

Rapid evolution of weed biological control agents (BCAs) to new biotic and abiotic conditions is poorly understood and so far only little considered both in pre-release and post-release studies, despite potential major negative or positive implications for risks of nontargeted attacks or for colonizing yet unsuitable habitats, respectively. Provision of genetic resources, such as assembled and annotated genomes, is essential to assess potential adaptive processes by identifying underlying genetic mechanisms. Here, we provide the first sequenced genome of a phytophagous insect used as a BCA, that is, the leaf beetle Ophraella communa, a promising BCA of common ragweed, recently and accidentally introduced into Europe. A total 33.98 Gb of raw DNA sequences, representing ∼43-fold coverage, were obtained using the PacBio SMRT-Cell sequencing approach. Among the five different assemblers tested, the SMARTdenovo assembly displaying the best scores was then corrected with Illumina short reads. A final genome of 774 Mb containing 7,003 scaffolds was obtained. The reliability of the final assembly was then assessed by benchmarking universal single-copy orthologous genes (>96.0% of the 1,658 expected insect genes) and by remapping tests of Illumina short reads (average of 98.6 ± 0.7% without filtering). The number of protein-coding genes of 75,642, representing 82% of the published antennal transcriptome, and the phylogenetic analyses based on 825 orthologous genes placing O. communa in the monophyletic group of Chrysomelidae, confirm the relevance of our genome assembly. Overall, the genome provides a valuable resource for studying potential risks and benefits of this BCA facing environmental novelties.© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.