OsWOX13 functions as a heading signal transducer from integrator Ehd1 to florigen for the accurate regulation of rice heading date

Appropriate heading date is an important safeguard for stabilizing rice yield and quality. Heading integrator Ehd1 and florigen Hd3a are crucial for rice heading. However, the mechanism by which Ehd1 transmits heading signals to Hd3a and the accurate regulation of Hd3a expression remains unclear. Here, we found that OsWOX13 functions as a signal transducer from Ehd1 to Hd3a for the accurate regulation of rice heading date. Ehd1 can directly bind to the OsWOX13 promoter, OsWOX13 in turn binds to the Hd3a promoter to activate its expression. OsWOX13 interacts with Hd3a to inhibit OsWOX13-mediated activation of Hd3a expression, that precisely controls Hd3a levels. Meanwhile, late-heading phenotypes were observed in the ehd1, Oswox13, Oswox13 ehd1, hd3a, and Oswox13 hd3a, demonstrating that Ehd1, OsWOX13, and Hd3a coordinately regulate rice heading date. Furthermore, OsWOX13 can be divided into two haplotypes, Hap-T and Hap-C. Ehd1 elevated OsWOX13 expression in Hap-T compared with Hap-C. Longjing 31T-C (carrying Hap-C) exhibited later heading dates than Longjing 31 (carrying Hap-T). Rice varieties carrying the Hap-T are predominantly cultivated in high-latitude regions. This study provides genetic resources and a theoretical foundation for improving the regional and climatic adaptability of rice.