Regulatory Role of CjDREB2C in Salt Tolerance Through Fatty Acid Biosynthesis and ROS Scavenging in Citrus junos
Salt stress is a major abiotic stress which severely hinders crop production. Despite this, the regulatory mechanisms governing salt resistance in citrus\u2014a perennial woody fruit crop\u2014remain inadequately understood. We investigated the function of the transcriptional regulator CjDREB2C by generating and characterizing transgenic over-expression citrus lines and gene editing knockout lines, as well as exploring its putative targets through a chromatin immunoprecipitation sequencing (ChIP-seq) approach combined with transcriptomic data. We demonstrated that CjDREB2C induces the accumulation of unsaturated fatty acids and directly activates the expression of FLORAL TRANSITION AT THE MERISTEM1 (FTM1), a gene involved in oleic acid synthesis. Furthermore, we found that CjDREB2C directly activates SIMILAR TO RCD ONE 5 (SRO5), which is involved in the degradation of reactive oxygen species (ROS). Taken together, our findings demonstrate that CjDREB2C, as a positive regulator, functions in salt tolerance by regulating genes involved in unsaturated fatty acid biosynthesis and ROS scavenging.