title: 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.
  
  
  RESULTS
  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.
authors.affiliation: Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Wen
authors.initials: W
authors.lastname: Xie
authors.forename: Qing-shu
authors.initials: QS
authors.lastname: Meng
authors.forename: Qing-jun
authors.initials: QJ
authors.lastname: Wu
authors.forename: Shao-li
authors.initials: SL
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.forename: Ni-na
authors.initials: NN
authors.lastname: Yang
authors.forename: Ru-mei
authors.initials: RM
authors.lastname: Li
authors.forename: Xiao-guo
authors.initials: XG
authors.lastname: Jiao
authors.forename: Hui-peng
authors.initials: HP
authors.lastname: Pan
authors.forename: Bai-ming
authors.initials: BM
authors.lastname: Liu
authors.forename: Qi
authors.initials: Q
authors.lastname: Su
authors.forename: Bao-yun
authors.initials: BY
authors.lastname: Xu
authors.forename: Song-nian
authors.initials: SN
authors.lastname: Hu
authors.forename: Xu-guo
authors.initials: XG
authors.lastname: Zhou
authors.forename: You-jun
authors.initials: YJ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001419:Bacteria / Q000235:genetics*; D001483:Base Sequence; D019295:Computational Biology; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D015723:Gene Library; D006430:Hemiptera / Q000235:genetics* / Q000382:microbiology*; D054884:Host-Pathogen Interactions; D007305:Insecticide Resistance / Q000235:genetics*; D056186:Metagenomics / Q000379:methods; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000633:toxicity; D010078:Oxazines / Q000633:toxicity; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA / Q000379:methods; D013559:Symbiosis; D000077922:Thiamethoxam; D013844:Thiazoles / Q000633:toxicity; D059467:Transcriptome / Q000235:genetics*
chemical_list: D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D013844:Thiazoles; D000077922:Thiamethoxam