Glycolate oxidase gene family identification and functional analyses in cotton resistance to wilt.

Glycolate oxidase (GOX) plays an important role in the regulation of photorespiration and photosynthesis in plants. However, as one of the main enzymes to produce the second messenger hydrogen peroxide (HO), its functions in response to pathogens are still poorly understood. In this study, we carried out genome-wide identification, and 14 GOX genes were identified in . These GOX genes are located on 10 chromosomes and divided into hydroxyacid-oxidases (HAOX) and GOX groups. After infection with Kleb., six GOX gene expression levels were changed. Moreover, HO, salicylic acid (SA), and the content and activity of GOX increased in cotton. --silenced plants showed more wilting than control plants after infection with . Additionally, HO accumulation and SA content were reduced in --silenced plants. The expression levels of , and and the lignin content of the silenced plants were significantly lower than those of the control plants. These results indicate that GhHAOX2-D is a positive regulator of wilt tolerance in cotton and may promote HO accumulation via the synergistic effects of GOX genes and SA. Collectively, GOX genes play an important role in cotton resistance to wilt.