Dataset Information

Pyrosequencing the Bemisia tabaci transcriptome reveals a highly diverse bacterial community and a robust system for insecticide resistance.

ABSTRACT: BACKGROUND: Bemisia tabaci (Gennadius) is a phloem-feeding insect poised to become one of the major insect pests in open field and greenhouse production systems throughout the world. The high level of resistance to insecticides is a main factor that hinders continued use of insecticides for suppression of B. tabaci. Despite its prevalence, little is known about B. tabaci at the genome level. To fill this gap, an invasive B. tabaci B biotype was subjected to pyrosequencing-based transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes. METHODOLOGY AND PRINCIPAL FINDINGS: Using Roche 454 pyrosequencing, 857,205 reads containing approximately 340 megabases were obtained from the B. tabaci transcriptome. De novo assembly generated 178,669 unigenes including 30,980 from insects, 17,881 from bacteria, and 129,808 from the nohit. A total of 50,835 (28.45%) unigenes showed similarity to the non-redundant database in GenBank with a cut-off E-value of 10-5. Among them, 40,611 unigenes were assigned to one or more GO terms and 6,917 unigenes were assigned to 288 known pathways. De novo metatranscriptome analysis revealed highly diverse bacterial symbionts in B. tabaci, and demonstrated the host-symbiont cooperation in amino acid production. In-depth transcriptome analysis indentified putative molecular markers, and genes potentially involved in insecticide resistance and nutrient digestion. The utility of this transcriptome was validated by a thiamethoxam resistance study, in which annotated cytochrome P450 genes were significantly overexpressed in the resistant B. tabaci in comparison to its susceptible counterparts. CONCLUSIONS: This transcriptome/metatranscriptome analysis sheds light on the molecular understanding of symbiosis and insecticide resistance in an agriculturally important phloem-feeding insect pest, and lays the foundation for future functional genomics research of the B. tabaci complex. Moreover, current pyrosequencing effort greatly enriched the existing whitefly EST database, and makes RNAseq a viable option for future genomic analysis.

SUBMITTER: Xie W

PROVIDER: S-EPMC3340392 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Pyrosequencing the Bemisia tabaci transcriptome reveals a highly diverse bacterial community and a robust system for insecticide resistance.

Xie Wen W Meng Qing-shu QS Wu Qing-jun QJ Wang Shao-li SL Yang Xin X Yang Ni-na NN Li Ru-mei RM Jiao Xiao-guo XG Pan Hui-peng HP Liu Bai-ming BM Su Qi Q Xu Bao-yun BY Hu Song-nian SN Zhou Xu-guo XG Zhang You-jun YJ

PloS one 20120430 4

<h4>Background</h4>Bemisia tabaci (Gennadius) is a phloem-feeding insect poised to become one of the major insect pests in open field and greenhouse production systems throughout the world. The high level of resistance to insecticides is a main factor that hinders continued use of insecticides for suppression of B. tabaci. Despite its prevalence, little is known about B. tabaci at the genome level. To fill this gap, an invasive B. tabaci B biotype was subjected to pyrosequencing-based transcript ...[more]

PMID: 22558125

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Project description:The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), and the viruses it transmits, are a major constraint to vegetable crops, worldwide. Although the whitefly is usually controlled using chemical pesticides, biological control agents constitute an important component in integrated pest management programs. One of these agents is the wasp Eretmocerus mundus (Mercet) (Hymenoptera: Aphelinidae). E. mundus lays its egg on the leaf underneath the pupa of B. tabaci. First instars of the wasp hatch and penetrate the whitefly larvae. Initiation of parasitization induces the host to form a cellular capsule around the parasitoid. Around this capsule, epidermal cells multiply and thick layers of cuticle are deposited. The physiological and molecular processes underlying B. tabaci-E. mundus interactions have not been investigated so far. We have used a cDNA microarray containing 6,000 expressed sequence tags (ESTs) from the whitefly genome to study the parasitoid-whitefly interaction. We compared RNA samples collected across two time points of the parasitization process: when the parasitoid first instar started the penetration process and once it had fully penetrated the host. The results clearly indicated that genes known to be part of the defense pathways described in other insects are also involved in the response of B. tabaci to parasitization by E. mundus. Some of the responses observed included the repression of a serine protease inhibitor (serpin) and the induction of a melanization cascade. A second set of genes that strongly responded to parasitization included bacterial genes encoded by whitefly symbionts. Quantitative real-time PCR and FISH analyses showed that proliferation of Rickettsia, a facultative secondary symbiont, was strongly induced following the initiation of the parasitization process, a result that supported previous reports suggesting that endosymbionts may be involved in the insect host resistance to various environmental stresses. This is the first study examining the transcriptional response of a hemipteran insect to the attack of a biological control agent (Hymenopterous parasitoid), using a new genomic approach developed for this insect pest. The defense response in B. tabaci seems to resemble that of model organisms such as Drosophila melanogaster. Moreover, endosymbionts of B. tabaci seem to play a role in the response to parasitization, and this is supported by previously published results from aphids. Keywords: time course

Project description:BackgroundSpecies within the Bemisia tabaci cryptic species complex can cause significant crop damage. We used high-throughput amplicon sequencing to identify the species composition and resistance allele genotypes in field populations from cotton fields in Australia. For selected populations, the resistance phenotype was determined in bioassays and compared with sequencing data.ResultsA metabarcoding approach was used to analyse the species composition in 144 field populations collected between 2013 and 2021. Two mixed AUS I and MEAM1 populations were detected, whereas the remaining 142 populations consisted of MEAM1 only. High-throughput sequencing of organophosphate and pyrethroid resistance gene amplicons showed that the organophosphate resistance allele F331W was fixed (> 99%) in all MEAM1 populations, whereas the pyrethroid resistance allele L925I in the voltage-gated sodium channel gene was detected at varying frequencies [1.0%-7.0% (43 populations); 27.7% and 42.1% (two populations); 95%-97.5% (three populations)]. Neither organophosphate nor pyrethroid resistance alleles were detected in the AUS I populations. Pyrethroid bioassays of 85 MEAM1 field-derived populations detected no resistance in 51 populations, whereas 32 populations showed low frequency resistance, and 2 populations were highly resistant.ConclusionsWe demonstrate that high-throughput sequencing and bioassays are complementary approaches. The detection of target site mutations and the phenotypic provides a comprehensive analysis of the low-level resistance to pyrethroids that is present in Australian cotton farms. By contrast, a limited survey of whitefly populations from horticulture found evidence of high-level resistance against pyrethroids. Furthermore, we found that the F331W allele (linked to organophosphate resistance) is ubiquitous in Australian MEAM1. © 2022 Commonwealth of Australia. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Dataset Information

Pyrosequencing the Bemisia tabaci transcriptome reveals a highly diverse bacterial community and a robust system for insecticide resistance.

Publications

Pyrosequencing the Bemisia tabaci transcriptome reveals a highly diverse bacterial community and a robust system for insecticide resistance.

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