GENETIC ENHANCEMENT FOR RESISTANCE TO BIOTIC AND ABIOTIC STRESSES IN HARD WINTER WHEAT
Location: Hard Winter Wheat Genetics Research Unit
Title: The Gut Transcriptome of the Hessian Fly (Mayetiola Destructor), a Member of the Gall Midges
Submitted to: Biomed Central (BMC) Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 16, 2010
Publication Date: April 1, 2010
Citation: Zhang, S., Shukle, R. H., Mittapalli, O., Zhu, Y. C., Reese, J. C., Wang, H., Hua, B.Z., Chen, M.S. 2010. The gut transcriptome of a gall midge, Mayetiola destructor. Journal of Insect Physiology. 56:1198-1206.
Interpretive Summary: Hessian fly (Mayetiola destructor) is a serious pest of wheat and a model for the study of gall midge/plant interactions. The insect pest is controlled mainly through deploying resistant wheat. However, the rapid development of biotypes has made resistance in host plants short-lived, lasting for only 6-8 years for a specific resistance gene. Analysis of genes expressed in the gut of Hessian fly could lead to a better understanding of the mechanism for host toxicity, which may lead to improved durability of plant resistance. Analysis of gut genes could also provide targets for alternative strategies for controlling this pest using novel types of transgenes. This research systematically analyzed the genes expressed in the gut of Hessian fly larvae, which provides a foundation for further research on the function of individual genes and for identification of potentially useful targets.
Over 10,000 Expressed Sequence Tags (ESTs) were generated and assembled into 2,007 clusters (contigs and singletons). The most striking feature of the Hessian fly larval transcriptome is the existence of a large number of transcripts coding for so-called small secretory proteins (SSP) with amino acids less than 250. Eleven of the 30 largest clusters were SSP transcripts with the largest cluster containing 11.3% of total ESTs. Micorarray and qPCR analyses of representative SSP transcripts revealed that most of them were predominantly present in the gut tissue and the transcript levels of many SSP were affected by plant types on which larvae feed. Transcripts coding for diverse digestive enzymes, detoxification and metabolic proteins were also identified. The putative digestive enzymes included serine proteinases (trypsins and chymotrypsins), cysteine proteases, aspartic protease, endo-oligopeptidase, aminopeptidases, carboxypeptidases, and a-amylases. Putative detoxification proteins included cytochrome P450s, glutathione S-transferases, peroxidases, ferritins, catalase, peroxiredoxins, and others. This study represents the first global analysis of gut transcripts from a gall midge. The identification of a large number of SSP transcripts in the Hessian fly larval gut provides a foundation for future study on the functions of these genes. The impact of plant types on the expression of SSP genes suggests that the SSP genes may play critical roles in Hessian fly – plant interactions and are potentially useful targets for pest management. The discovery of transcripts encoding various kinds of digestive enzymes and detoxification proteins also provides important sources for future studies on these groups of genes.