The chitinase gene ZmChi7 confers salt stress tolerance by modulating the ROS homeostasis in maize

Salt stress significantly impairs crop growth and development, often resulting in substantial reductions in agricultural yield. Chitinases play multifaceted roles in plant physiology, participating in processes such as tissue remodeling, nutrient uptake, and immune defense mechanisms. However, research on plant chitinases has predominantly focused on biotic stress responses, with limited exploration of their functions under abiotic stress conditions. Here, we report the identification and functional characterization of ZmChi7, a salt stress-inducible chitinase-encoding gene in maize. Genetic and phenotypic analyses revealed that the zmchi7 mutant exhibits markedly enhanced sensitivity to salt stress compared to wild-type plants, characterized by severe growth inhibition, excessive accumulation of reactive oxygen species (ROS), and elevated transcription of ROS-scavenging genes. Additionally, Overexpression of ZmChi7 in Arabidopsis resulted in improved salt resistance and significant increase the root length compared to the wild type. Furthermore, mutation of ZmChi7 significantly reduced plant height through alterations in lignin content, indicating a dual role for this gene in both stress tolerance and developmental regulation. Collectively, these findings advance our understanding of chitinase-mediated mechanisms in plant adaptation to salt stress by modulating the ROS homeostasis and identify ZmChi7 as a potential target for engineering salt-resistant crops.