Unveiling the role and crosstalk of hydrogen sulfide with other signalling molecules enhances plant tolerance to water scarcity.

Drought, a major factor limiting global crop yields, disrupts plant growth, water interactions, and overall water use efficiency. Hydrogen sulfide (HS), a key gasotransmitter, has become a crucial signalling molecule in plant biology. It promotes growth and development while significantly contributing to the plant's response to various abiotic stresses, including drought. This review explores how H₂S mitigates drought stress in plants and crosstalks with various signalling molecules such as nitric oxide, melatonin, abscisic acid, γ-aminobutyric acid, polyamines, and others. It highlights how these interactions, with H₂S acting either upstream or downstream, enhance the plant's stress response and resistance. Furthermore, H₂S signalling involves persulfidation, in which H₂S modifies protein thiol groups to protect against oxidative damage. The review underscores the key role of protein persulfidation in reducing reactive oxygen species accumulation and maintaining redox homeostasis under drought stress. The review aims to elucidate the role of H₂S in stress relief and expand our knowledge of how it contributes to plant resistance during water scarcity by examining its regulatory mechanisms and interactions. Additionally, it proposes practical strategies for enhancing agricultural practices in the face of growing drought conditions, offering methods to leverage H₂S for improving plant tolerance to water scarcity.