Submitted to: NCB-ESA North Central Branch Entomological Society of America
Publication Type: Abstract Only
Publication Acceptance Date: 2/20/2005
Publication Date: 3/20/2005
Citation: Giovanini, M., Ohm, H., Williams, C.E. 2005. A novel wheat lectin gene is up-regulated in resistant wheat plants during Hessian fly larval feeding. NCB-ESA North Central Branch Entomological Society of America. http://esa.ent.iastate.edu/confreg. Interpretive Summary:
Technical Abstract: The identification of wheat genes induced during Hessian fly larval feeding is a powerful tool to understand the molecular mechanism by which wheat plants protect themselves against Hessian fly larval attacks and also to develop another means of controlling this devastating wheat pest. Resistance is achieved when plants carrying the Hessian fly R (resistance) gene recognize its correspondent Avr (avirulent) gene in the fly which activates a defense response that cause larval death; otherwise, the neonate fly larvae feed on crown tissue of seedlings inducing a permanent stunting phenotype characterizing a susceptible host. This gene-for-gene interaction between wheat and Hessian fly lacks elucidation of the molecular basis for understanding the death of avirulent larvae. Our intensive effort to find genes responding to larval feeding resulted in the cloning of a novel wheat lectin gene, Hfr-3, which is highly up-regulated in resistant plants during the critical first four days of larval feeding. Q-RT-PCR data showed a 3000-fold increase in the level of Hfr-3 mRNA in resistant plants challenged with Hessian fly larvae. This result was confirmed by quantitative northern blots. The deduced amino acid sequence of this lectin is 70% identical to Wheat Germ Agglutinin (WGA) and has three putative chitin-binding domains. Due to the specific binding properties of lectins to glycoproteins, this novel lectin could possibly be the major component involved in defense response by binding to the digested track of the larvae causing its death. Experiments are in process to elucidate the defense mechanism of wheat to Hessian fly.