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. •Black rot (BR)can lead to serious effects on cabbage growth, especially Xcc inhibits photosynthesis by affecting chlorophyll content, photosynthetic properties, chlorophyll fluorescence, expression of the main enzymes of the Calvin cycle and related genes in the early stages of plant infection.•Exogenous H2S significantly reduced chlorophyll degradation increasing light energy utilization.•Hydrogen sulfide also improves gas exchange conditions and affects chlorophyll fluorescence, increases photosynthetic efficiency, and attenuates BR induced PSII photoinhibition.•H2S could increase the activity and gene expression of Calvin cycle related enzymes and maintain the normal operation of the fixation, reduction and renewal phases of the Calvin cycle in cabbage under BR stress.