TY - JOUR AU1 - Yin, Yanbin AU2 - Yan, Zhiqiang AU3 - Guan, Jianing AU4 - Huo, Yiqiong AU5 - Wang, Tianqiong AU6 - Li, Tong AU7 - Cui, Zhibo AU8 - Ma, Wenhong AU9 - Wang, Xiaoxue AU1 - Chen, Wenfu AB - Flowering time is one of the most important agronomic traits affecting the adaptation and yield of rice (Oryza sativa). Heading date 1 (Hd1) is a key factor in the photoperiodic control of flowering time. In this study, two basic helix-loop-helix (bHLH) transcription factors, Hd1 Binding Protein 1 (HBP1) and Partner of HBP1 (POH1) were identified as transcriptional regulators of Hd1. We generated knockout mutants of HBP1 and ectopically expressed transgenic lines of the two bHLH transcription factors and used these lines to investigate the roles of these two factors in regulating flowering time. HBP1 physically associated with POH1 forming homo- or heterodimers to perform their functions. Both HBP1 and POH1 bound directly to the cis-acting elements located in the promoter of Hd1 to activate its expression. CRISPR/Cas9-generated knockout mutations of HBP1, but not POH1 mutations, promoted earlier flowering time; conversely, HBP1 and POH1 overexpression delayed flowering time in rice under long-day and short-day conditions by activating the expression of Hd1 and suppressing the expression of Early heading date 1 (Ehd1), Heading date 3a (Hd3a), and Rice Flowering locus T 1 (RFT1), thus controlling flowering time in rice. Our findings revealed a mechanism for flowering time control through transcriptional regulation of Hd1 and laid theoretical and practical foundations for improving the growth period, adaptation, and yield of rice. TI - Two interacting basic helix-loop-helix transcription factors control flowering time in rice JF - PLANT PHYSIOLOGY DO - 10.1093/plphys/kiad077 DA - 2023-02-09 UR - https://www.deepdyve.com/lp/oxford-university-press/two-interacting-basic-helix-loop-helix-transcription-factors-control-GUNFPzuBat SP - 205 EP - 221 VL - 192 IS - 1 DP - DeepDyve ER -