Effect of hydrogen sulfide on cabbage photosynthesis under black rot stress

Hydrogen sulfide (H₂S), as a potential gaseous signaling molecule, is involved in mediating biotic and abiotic stress in plants. Currently, there are no studies investigating the mechanism by which H₂S improves photosynthesis under black rot (BR) stress caused by Xanthomonas campestris pv. Campestris (Xcc). In this study, we investigated the effect of exogenous H₂S on Xcc induced photosynthetic impairment in cabbage seedlings. BR has an inhibitory effect on the photosynthetic ability of cabbage seedlings. Xcc infection can significantly reduce the chlorophyll content, photosynthetic characteristics, chlorophyll fluorescence, Calvin cycle related enzyme activity and gene expression in cabbage leaves. The use of H₂S can alleviate this inhibitory effect, reduce chlorophyll decomposition, improve gas exchange, enhance the activity of Calvin cycle related enzymes, and increase the expression of related genes. Transcriptome analysis showed that all differential genes related to photosynthesis were up regulated under H₂S treatment compared to normal inoculation. Therefore, spraying exogenous H₂S can improve the photosynthetic capacity of cabbage seedlings, reduce Xcc induced photoinhibition, and improve plant resistance.