Submitted to: Journal of Insect Physiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/19/2010
Publication Date: 7/1/2010
Publication URL: hdl.handle.net/10113/43395
Citation: Shukle, R.H., Subramanyam, S., Williams, C.E. 2010. Ultrastructural Changes in the Midgut of Hessian Fly Larvae Feeding on Resistant Wheat. Journal of Insect Physiology. 56:754-760. Interpretive Summary: The Hessian fly is a major pest of wheat in all the production regions of the United States. Wheat resistant to larval Hessian fly attack is the most economical and environmentally sound method of control; however, the ability of the pest to overcome formerly resistant wheat poses a threat to wheat production. To combat this there is a need to understand the mechanisms by which resistant plants are able to prevail against Hessian fly attack. Through an electron microscopy study we have documented that the midgut is a major target of toxic compounds produced by resistant plants and that the lining of the midgut is rapidly disrupted within hours of larvae initiating feeding on resistant wheat. Knowledge gained from this study will help breeders and scientists facing the challenge of devising innovative methods to ensure the durability of resistant wheat to prevent yield loss due to Hessian fly infestation. The agricultural community (crop producers and commodity groups) will benefit from improved pest control that increases yield and quality without increasing costs.
Technical Abstract: The Hessian fly, Mayetiola destructor (Say), is present in all wheat producing regions of the United States and is the most important insect pest in the southeastern soft-winter-wheat region. Genotypes of the pest that can overcome formerly resistant wheat continue to appear and pose a threat to wheat production. There is a need to better understand the mechanisms by which resistant plants are able to prevail over larval attack. The goal of the present study was to determine if ultrastructural changes occur in the midguts of larvae feeding on resistant wheat compared to larvae feeding on susceptible wheat and larvae experiencing starvation while removed from the plant. Results revealed that within three hours of initiating feeding on resistant wheat midgut microvilli were disrupted and after six hours microvilli were absent. The disruptions in microvilli observed in larvae feeding on resistant wheat were similar to those reported for midgut microvilli of Drosophila melanogaster larvae fed a diet containing 1% wheat germ agglutinin. Results from the present ultrastructural study, coupled with previous gene expression studies, confirm the larval Hessian fly’s midgut is a major target of toxic plant compounds that play a pivotal role in resistance.