Recently, the Rice Reproductive Developmental Biology team from China National Rice Research Institute (CNRRI) of Chinese Academy of Agricultural Sciences (CAAS) has revealed that NF-YB1-YC12-bHLH144 complex directly activates Wx to regulate grain quality in rice (Oryza sativa L.). The results have been published in Plant Biotechnology Journal with Dr. Babatunde Kazeem Bello and Dr. Hou Yuxuan as the co-first author and Dr. Zhang Jian as the corresponding author, who is the chief of the Rice Reproductive Developmental Biology team of CNRRI.

Identification of seed development regulatory genes is the key for the genetic improvement of rice grain quality. In this study, researchers identified and confirmed that the transcription factors NF-YB1, NF-YC12 and bHLH144 which are all specifically expressed in rice grains, formed heterotrimer complex by the binding of NF-YB1 to NF-YC12 and then bHLH144 in a sequential order. Knock-out of each of the complex genes resulted in alteration of grain qualities in all the mutants as well as reduced grain size in crnf-yb1 and crnf-yc12. NF-YB1 binds directly to the "G-box" domain of the key granule-bound starch synthase gene Wx promoter and activates Wx transcription hence to regulate rice grain quality, while NF-YC12 and bHLH144 maintain NF-YB1 stability from the degradation mediated by ubiquitin/26S proteasome. In all, it was found a novel grain quality regulatory pathway controlled by NF-YB1-YC12-bHLH144 complex, which has great potential for rice genetic improvement.

This study was supported by Agricultural Sciences and Technologies Innovation Program of Chinese Academy of Agricultural Sciences (CAAS) to Rice Reproductive Developmental Biology team, “Elite Youth” program (CAAS), National Natural Science Foundation of China (grant number: 31401366) and Chinese High-yielding Rice Transgenic Program (Grant No. 2016ZX08001004-001). More details are available on below link: https://onlinelibrary.wiley.com/doi/pdf/10.1111/pbi.13048.