Functional analysis of maize GRAS transcription factor gene ZmGRAS72 in response to drought and salt stresses

Abiotic stresses, such as drought and salt, are major factors affecting plant growth, development, and productivity. The GRAS gene family is a class of transcriptional regulators in plants that influence plant responses to various biotic and abiotic stresses. In this study, we cloned the maize (Zea mays L.) GRAS gene ZmGRAS72 and preliminarily analyzed its biological function. ZmGRAS72 was highly expressed in maize stems and young leaves, and was induced by abiotic stress and phytohormone treatments. Transient expression assays of maize protoplasts showed that ZmGRAS72 was localized to the nucleus. Heterologous expression of ZmGRAS72 in A. thaliana significantly improved plant tolerance to drought and salt stresses, increased chlorophyll content, decreased malondialdehyde content, and enhanced peroxidase activity. In addition, heterologous expression of ZmGRAS72 in A. thaliana upregulated or downregulated the expression levels of abscisic acid biosynthesis genes (NCED3), signaling genes (ABI1, ABI2, ABI4, and ABI5), and stress-related genes (RD22, RD29A, and KIN1) under abiotic stress. These results indicate that ZmGRAS72 may be responsive to abiotic stress, which forms a basis for further research on the mechanisms underlying the action of ZmGRAS72 in maize.