Submitted to: Comparative Biochemistry and Physiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/23/2007
Publication Date: 3/1/2008
Publication URL: hdl.handle.net/10113/36193
Citation: Mittapalli, O., Shukle, R.H. 2008. Molecular characterization and responsive expression of a defender against apoptotic cell death homologue from Hessian fly, Mayetiola destructor. Comparative Biochemistry and Physiology. Part B 149: 517-523. Interpretive Summary: The Hessian fly is a destructive pest of wheat in all production areas of the United States. However, despite its importance as a pest little is known about the way Hessian fly larvae interact with and feed on wheat plants. We are systematically analyzing genes expressed in Hessian fly larvae while they feed on susceptible and resistant wheat and have identified major digestive enzymes, detoxification/antioxidant enzymes, and immune defense proteins. In the present study, we have identified a gene from Hessian fly that belongs to a class of genes that defend against cell death in larvae when they feed on resistant wheat. The knowledge from our work on mechanisms employed by Hessian fly larvae while feeding on wheat provides a basis for understanding how the pest interacts with wheat plants. Scientists facing the challenge of devising innovative methods of pest control through genetic engineering and other contemporary approaches will benefit from this fundamental knowledge. The agricultural community (crop producers and commodity groups) will benefit from improved pest control that increases yield and quality without increasing costs.
Technical Abstract: Apoptosis or programmed cell death is an active process occurring in multicellular organisms to maintain growth and development. The Hessian fly, Mayetiola destructor, is rapidly emerging as a model insect species to study insect-plant interactions and to decipher some exceptional physiological phenomena. In this study, we report the characterization and expression profiles of a putative Hessian fly defender against apoptotic death (DAD1) homologue (designated MdesDAD1). The deduced amino acid sequence of MdesDAD1 revealed significant similarity (75% identity, 9e-42) to other insect and non-insect DAD1 sequences. Phylogenetic analysis grouped MdesDAD1 within a sub-clade consisting of other insect DAD1 homologues. Quantitative analysis indicated constitutive levels of MdesDAD1 mRNA in all the tissues examined but an altered expression pattern during development, wherein the highest mRNA levels were observed prior to pupation. Most interestingly, MdesDAD1 transcript was found to be up-regulated during incompatible (larvae reared on resistant wheat) Hessian fly/wheat interactions compared to compatible (larvae reared on susceptible wheat) interactions. These results suggest MdesDAD1 to have a putative role in the inhibition of unwanted apoptosis triggered during development and in incompatible Hessian fly/wheat interactions. The results obtained provide clues to plausible insect and host-plant factors that could be responsible for the induction of MdesDAD1.