Location: Hard Winter Wheat Genetics ResearchTitle: Unbalanced activation of glutathione metabolic pathways suggests potential involvement in plant defense against the gall midge mayetiola destructor in wheat Author
|Liu, Xuming - Kansas State University|
|Zhang, Shize - Kansas State University|
|Whitworth, Jeff - Kansas State University|
|Stuart, Jeffrey - Purdue University|
Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/31/2014
Publication Date: 1/28/2015
Publication URL: http://www.nature.com/srep/2015/150128/srep08092/full/srep08092.html
Citation: Liu, X., Zhang, S., Whitworth, J., Stuart, J.J., Chen, M. 2015. Unbalanced activation of glutathione metabolic pathways suggests potential involvement in plant defense against the gall midge mayetiola destructor in wheat. Scientific Reports. 5, Article number: 8092. doi:10.1038/srep08092.
Interpretive Summary: Hessian fly is a destructive pest of wheat. The insect pest is mainly controlled by deploying resistant wheat cultivars. Unfortunately, resistance conferred by major resistance genes is usually short-lived, lasting only for 3-8 years. To develop more durable resistant cultivars, we need a better understanding of the resistance mechanism in wheat to Hessian fly. Glutathione is a small peptide that plays a role in various physiological processes in nearly all organisms. In this study, we examined the changes in glutathione abundance and metabolic pathways in both resistant and susceptible plants following Hessian fly attack. We found that the abundance of total glutathione increased up to 60% in resistant plants within 72 hours following Hessian fly attack, but no increase in susceptible plants. We also found that the metabolic and recycling pathways of glutathione were unevenly regulated in infested resistant plants. Our results provide a foundation for elucidating the molecular processes involved in glutathione-mediated plant resistance to Hessian fly and potentially other pests as well.
Technical Abstract: Glutathione, a thiol tripeptide of '-glutamylcysteinylglycine, exists abundantly in nearly all organisms. Glutathione participates in various physiological processes involved in redox reactions by serving as an electron donor/acceptor. In this study, we found that the abundance of total glutathione increased up to 60% in resistant plants within 72 hours following attack by the gall midge Mayetiola destructor, the Hessian fly. The increase in total glutathione abundance, however, is coupled with an unbalanced activation of glutathione metabolic pathways. The activity and transcript abundance of glutathione peroxidases, which convert reduced glutathione (GSH) to oxidized glutathione (GSSG), increased in infested resistant plants. However, the enzymatic activity and transcript abundance of glutathione reductases, which convert GSSG back to GSH, did not change. This unbalanced regulation of the glutathione oxidation/reduction cycle indicates the existence of an alternative pathway to regenerate GSH from GSSG to maintain a stable GSSG/GSH ratio. Our data support the hypothesis that GSSG is transported from cytosol to apoplast to serve as an oxidant for class III peroxidases to generate reactive oxygen species for plant defense against Hessian fly larvae. Our results provide a foundation for elucidating the molecular processes involved in glutathione-mediated plant resistance to Hessian fly and potentially other pests as well.