GAMYB TF modulates bHLH142 and is homeostatically regulated by TDR TF during rice anther tapetal and pollen development

• Published in: Journal of experimental botany 2021-05
• Main Authors: Ko, Swee-Suak, Li, Min-Jeng, Ho, Yi-Cheng, Yu, Chun-Ping, Yang, Ting-Ting, Lin, Yi-Jyun, Hsing, Hung-Chien, Chen, Tien-Kuan, Jhong, Chung-Min, Li, Wen-Hsiung, Sun-Ben Ku, Maurice
• Format: Article
• Language: English
• ISSN: 1460-2431
• DOI: 10.1093/jxb/erab190

GAMYB, UDT1, TIP2/bHLH142, TDR, and EAT1/DTD are important transcription factors (TFs) that play a crucial role during rice pollen development. This study demonstrates that bHLH142 acts downstream of UDT1 and GAMYB and works as a "hub" in these two pollen pathways. We show that GAMYB modulates bHLH142 expression through specific binding to the MYB motif of bHLH142 promoter during early stage of pollen development; while TDR acts as a transcriptional repressor of the GAMYB modulation of bHLH142 by binding to the E-box close to the MYB motif on the promoter. The altered expression of TFs highlights the importance that a tight, precise, and coordinated regulation among these TFs is essential for normal pollen development. Most notably, this study illustrates the regulatory pathways of GAMYB and UDT1 that rely on bHLH142 in a direct and an indirect manner, respectively, and function in different tissues with distinct biological functions during pollen development. This study advances our understanding of the molecular mechanisms of rice pollen development.