Hydrogen Sulfide Is Involved in Melatonin-Induced Drought Tolerance in Maize (Zea mays “Beiqing340”)
2025
Jianhong Ren | Xinru Yan | Wenjing Wu | Xiaoxiao Yang | Yanhui Dong
Melatonin and hydrogen sulfide (H2S) have both been demonstrated to enhance plant drought tolerance. However, the relationship between melatonin and H2S during the drought resistance response remains unclear. In this study, under drought stress, the synthesis pathways for both melatonin and H2S in maize seedlings were activated. The application of exogenous melatonin enhanced the expression of key genes, namely LCD and DCD, which are involved in H2S synthesis, thereby promoting the accumulation of H2S. Conversely, the application of NaHS did not significantly influence the expression of genes related to melatonin synthesis or the levels of endogenous melatonin. Melatonin enhanced drought tolerance in maize through the H2S signaling pathway, as evidenced by a 124.1% increase in the photosynthetic rate and improved activity of antioxidant enzymes. Specifically, there were increases of 66.5%, 75.6%, and 51.0% in the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), respectively. Furthermore, there was an elevation in the levels of osmotic regulatory substances and non-enzymatic antioxidants. The application of the H2S scavenger (HT) significantly inhibited the drought tolerance effects mediated by melatonin, whereas the melatonin synthesis inhibitor (p-CPA) did not exert a significant impact on the drought resistance induced by H2S. Overall, our findings suggest that H2S plays a role in the melatonin-mediated enhancement of drought tolerance in maize, primarily through coordinated modulation of osmotic balance and antioxidant defense systems.
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