OsELF3.1-OsCATA-Ghd7 Pathway Regulates Rice Heading

Rice, a critical global staple crop, relies heavily on heading date, a key agronomic trait marking the transition from vegetative to reproductive growth. Understanding the genetic regulation of heading date is vital for enhancing the adaptability of high-quality rice varieties across diverse geographical regions and for bolstering local food security. In this study, we uncover a novel role for OsCATA , a catalase gene, in the regulation of photoperiodic flowering in rice. We identified a novel allele of OsELF3.1 , whose mutation resulted in delayed heading. Further analyses revealed that OsELF3.1 physically interacts with OsCATA . Notably, OsCATA exhibits rhythmic expression patterns similar to OsELF3.1 and, when mutated, also delayed flowering. Expression analyses showed that the delayed heading phenotype could be attributed to elevated Ghd7 expression under both long-day (LD) and short-day (SD) conditions, with OsCATA expression positively regulated by OsELF3.1 . Double mutants of OsELF3.1 and OsCATA displayed a heading delay similar to the that of oself3.1 single mutant. Additionally, OsELF3.1 was shown to interact with Ghd7 in vivo , alleviating its suppression of Ehd1 . Luciferase assays confirmed that Ghd7 represses Ehd1 expression, while OsELF3.1 mitigates this repression. Collectively, our findings reveal that OsCATA is critical in suppressing Ghd7 expression through the OsELF3.1-OsCATA-Ghd7 transcriptional pathway, thereby regulating rice heading.