Cotton Chitinase GeneGhChi6Improves theArabidopsisDefense Response to Aphid Attack

Despite the involvement of many members of the chitinase family in the plant immune system, the exact functions of most chitinases remain poorly understood, especially in plant defense responses to phytophagous insects. Here, the geneGhChi6, which encodes a chitinase protein inGossypium hirsutum, was shown to be induced by cotton aphid feeding and mechanical wounding. Overexpression ofGhChi6inArabidopsisplants improved their defense response to aphids. The activities of chitinase and PPO inGhChi6transgenicArabidopsis plants were higher than those in wild-type plants. Callose deposition in leaves fromGhChi6transgenicArabidopsisplants was clearly increased compared with wild-type plants. The levels ofAtEDS1,AtPAD4, andAtEDS5in the SA signaling pathway were higher inGhChi6transgenicArabidopsisLine4 than those in wild-type plants, while the expression levels ofAtLOX2in the JA signaling pathway andAtEIN2in the ethylene signaling pathway were lower inGhChi6transgenicArabidopsisLine4 than those in wild-type plants. These results collectively showed that the cotton chitinase geneGhChi6modulated the plant defense response to aphid attack, which may help guide strategies for improving cotton aphid prevention.

Automated summary

The study showed that overexpression of the cotton chitinase gene GhChi6 in Arabidopsis plants enhanced defense response to aphids, as indicated by increased chitinase and PPO activities, callose deposition, and modulation of signaling pathways. These results suggest that GhChi6 plays a crucial role in mediating plant defense mechanisms against aphid attacks.