Effect of hydrogen sulfide on D1 protein in wheat under drought stress

Drought usually induces plant growth inhibition and oxidative damage. This report showed the protections of hydrogen sulfide (H2S) against drought-induced damage in wheat, which was manifested in the better growth, higher relative water content (RWC), lower thiobarbituric acid-reactive substances (TBARS), and hydrogen peroxide (H2O2) as well as the increased activities of superoxide dismutase (SOD) and catalase (CAT). Drought often causes photosystem II (PS II) damage, which was observed in the decreased potential photochemical efficiency (F-v/F-m), actual photochemical efficiency (UPS II), photochemical quenching (qP), electron transfer rate (ETR), and increased non-photochemical quenching (qN), however, these effects could be alleviated by NaHS (H2S donor). D1 protein in PS II reaction center is the most sensitive target of PS II damage. Compared to water treatment, a higher level of transcription but less D1 protein and phosphorylated D1 protein was detected in wheat leaves when exposed to NaHS under drought stress, which may result from the higher expression of STN8 (catalyze D1 protein phosphorylation) and D1 protein degradation-related gene (Deg1, Deg5, Deg8, FtsH2, and FtsH5). These results suggested that H2S alleviated drought-induced PS II damage owing to fast D1 protein turnover rather than D1 protein content.