|Shatters, Robert - Bob|
Submitted to: Biomed Central (BMC) Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2006
Publication Date: 4/11/2006
Citation: Leshkowitz, D., Gazit, S., Reuveni, E., Ghanim, M., Czosnek, H., McKenzie, C., Shatters Jr., R.G., Brown, J.K. 2006. Whitefly (Bemisia tabaci) genome project: analysis of sequenced clones from egg, instar, and adult (viruliferous and non-viruliferous) cDNA libraries. BMC Genomics. 7(1):79. Interpretive Summary: The past three decades have witnessed a dramatic increase in interest in the whitefly Bemisia tabaci Gennadius owing to the damage it causes to a large number of agriculturally important crops, its specialized feeding in the phloem, the propensity it has for developing insecticide resistance, and its ability to serve as a vector of economically important plant viruses. Among the plant viruses to be transmitted by B. tabaci are those in the genus Begomovirus (family, Geminiviridae). Understanding the genetic components responsible for the whitefly traits that make it a worldwide economic problem will aid in the development of novel biologically-based and environmentally-sound sustainable control strategies. Surprisingly, little is known about the genome of this whitefly. This research was conducted to develop a large database of genetic information on B. tabaci that will be made publicly available for researchers studying the genetics of this important pest insect. Genetic data was collected and characterized with emphasis on discovery of genes that were involved in Begomovirus vectoring and influence of insect developmental stage and Begomovirus’ on whitefly gene expression was analyzed.
Technical Abstract: To address a general shortage of genomic sequence information in the whitefly Bemisia tabaci Gennadius, we have constructed three cDNA libraries for non-viruliferous whiteflies (eggs, immature instars, and adults)and two from adult insects that fed on tomato plants infected by two geminiviruses: Tomato yellow leaf curl virus (TYLCV)and Tomato mottle virus (ToMoV). In total,18,976 cDNA sequences were determined. After quality control, and removal of 4,860 mitochondrial sequences, 9109 expression sequence tags (ESTs) remained. The number of contigs represented by a single sequence was 3,843. Comparisons with public databases indicated that the libraries contained genes involved in cellular and developmental processes. In addition, approximately 1,000 bp aligned with the genome of the B. tabaci endosymbiotic bacterium Candidatus Portiera aleyrodidarum, originating primarily from the egg and instar libraries. Apart from the mitochondrial sequences, the longest and most abundant EST encoded vitellogenin, which originated from whitefly adult libraries, indicating that much of the gene expression in this insect is directed toward the production of eggs. This is the first functional genomics project involving a hemipteran (Homopteran) insect from the subtropics/tropics. The B. tabaci EST database now provides an important tool to initiate identification of whitefly genes involved in development, behaviour, and B. tabaci-mediated begomovirus transmission.