Unbalanced Activation of Glutathione Metabolic Pathways Suggests Potential Involvement in Plant Defense against the Gall Midge Mayetiola destructor in Wheat

Abstract

Glutathione, γ-glutamylcysteinylglycine, exists abundantly in nearly all organisms. Glutathione participates in various physiological processes involved in redox reactions by serving as an electron donor/acceptor. We found that the abundance of total glutathione increased up to 60% in resistant wheat 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 suggest the possibility 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.

Reduced Glutathione Protects Subcellular Compartments From Pb-Induced ROS Injury in Leaves and Roots of Upland Cotton (Gossypium hirsutum L.)

“…Furthermore, GR activity was enhanced in the terminal and median leaves, but remained nearly unchanged in the groups treated with Pb alone and in combination with GSH. Previously, it was also observed that GSH levels were increased during stress conditions, but GR activity remained unchanged, pointing to the GSH de novo synthesis (Liu et al, 2015). In current study, Pb contents and GSH concentrations in terminal and median leaves and primary and secondary roots were also measured (Figure 2).…”

Comparative transcriptome analysis by Tilletia horrida infection in resistant and susceptible rice (Oryza sativa L.) male sterile lines reveals candidate genes and resistant mechanisms

“…Flavonoid and tyrosine ammonialyases play important roles in plant defence early during infection [43]. In addition, glutathione and some unsaturated fatty acids were also participates in signaling of plant defense against biotic and abiotic stresses [44]. These results indicated that these four pathways may play important role for ability of Jiangcheng 3A resistance T.…”

Regulation of boron toxicity responses via glutathione-dependent detoxification pathways at biochemical and molecular levels in Arabidopsisthaliana

“…In other words, despite a stable level of GSH, a dramatic increase in GST activity may indicate undisturbed usage and recycling of GSH. Associatively, possible alternative pathways to convert GSSG back to GSH through class III peroxidases have been suggested due to uncorrelated results between GR and glutathione peroxidase in wheat (Liu et al, 2015).…”