RcLOG7-1 of castor bean plays dual roles in enhancing drought and salt stress tolerance

Heterologous overexpression, transcriptomics, and physiology confirm RcLOG7-1 enhances plant drought and salt tolerance. The specific phosphohydrolase LONELY GUY (LOG) is involved in various biological processes of plant growth and development. However, research on the regulatory role of castor bean LOG under drought and salt stresses is limited. Here, we report the dual positive regulatory effects of the RcLOG7-1 gene under both drought and salt stresses in genetically modified Arabidopsis thaliana. Drought and salinity conditions significantly induced the transcription of RcLOG7-1. Subcellular localization results indicate that RcLOG7-1 was located in the cytoplasm. Overexpression of RcLOG7-1 in Arabidopsis enhanced drought and salt stresses tolerance. Through RNA-seq and physiological assessments, RcLOG7-1 modulated the expression of genes involved in glutathione metabolism, phenylpropanoid biosynthesis, and proline synthesis under drought and salt stresses, thereby enhancing antioxidant enzyme activity and lignin content in transgenic Arabidopsis. This resulted in improved scavenging of active oxygen free radicals. Furthermore, RcLOG7-1 influenced plant hormone signal transduction, particularly cytokinin synthesis (CTK), leading to elevated CTK levels in transgenic Arabidopsis compared to wild type. In summary, this study provides data supporting the function of LOG genes in stressed conditions, facilitating and accelerating molecular breeding for stress tolerance in castor bean.