Transcription factor bZIP65 delays flowering via suppressing expression in rice.

Unlabelled: Flowering time is one of the most fundamental factors that determine the distribution and final yield of rice. Ehd1 (Early heading date 1) is a B-type response regulator which functions as a flowering time activator. Although diverse flowering time genes have been reported as regulatory factors of expression, the potential regulators of largely remain to be identified. Here, we identified a basic leucine zipper transcription factor bZIP65, a homolog of bZIP71, as a new negative regulator of . The overexpression of delays flowering, while mutants have similar flowering time to SJ2 (Songjing2) in both long-day and short-day conditions. Biochemically, bZIP65 associates with promoter and transcriptionally represses the expression of . Moreover, we found that bZIP65 enhances H3K27me3 level of . Taken together, we cloned a new gene, , regulating rice heading date, and uncovered the mechanism of bZIP65 delaying flowering time, where bZIP65 increases the H3K27me3 level of and transcriptionally represses the expression of , similar to its homolog bZIP71.

Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01334-4.