NF‐YB1‐YC12‐bHLH144 complex directly activates Wx to regulate grain quality in rice (Oryza sativa L.)

• Published in: Plant biotechnology journal Vol. 17; no. 7; pp. 1222 - 1235
• Main Authors: Bello, Babatunde Kazeem, Hou, Yuxuan, Zhao, Juan, Jiao, Guiai, Wu, Yawen, Li, Zhiyong, Wang, Yifeng, Tong, Xiaohong, Wang, Wei, Yuan, Wenya, Wei, Xiangjin, Zhang, Jian
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.07.2019; John Wiley and Sons Inc
• Subjects: Amino acids; Analysis; Basic Helix-Loop-Helix Transcription Factors - metabolism; Biosynthesis; biotechnology; Chloroplasts; Deoxyribonucleic acid; DNA; DNA binding proteins; Edible Grain; Gene expression; Gene Expression Regulation, Plant; Genes; Genetic improvement; Genetic transcription; grain quality; Grain size; G‐box; Helix-loop-helix proteins (basic); heterotrimer complex; NDP-glucose-starch glucosyltransferase; nuclear factor Y; Oryza - enzymology; Oryza - genetics; Oryza sativa; Plant Proteins - genetics; Plant Proteins - metabolism; Proteasome 26S; proteasome endopeptidase complex; Proteins; Quality control; Quality management; Ribonucleic acid; Rice; rice (Oryza sativa L.); RNA; seed development; Seeds; sequence analysis; Starch; Starch synthase; Starch Synthase - genetics; Starch Synthase - metabolism; Transcription factors; Ubiquitin; Wx gene; China; rice (Oryza sativa L.); heterotrimer complex; nuclear factor Y; Wx gene; grain quality; G-box
• ISSN: 1467-7644; 1467-7652; 1467-7652
• DOI: 10.1111/pbi.13048

Summary Identification of seed development regulatory genes is the key for the genetic improvement in rice grain quality. NF‐Ys are the important transcription factors, but their roles in rice grain quality control and the underlying molecular mechanism remain largely unknown. Here, we report the functional characterization a rice NF‐Y heterotrimer complex NF‐YB1‐YC12‐bHLH144, which is formed 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. RNA‐seq analysis identified 1496 genes that were commonly regulated by NF‐YB1 and NF‐YC12, including the key granule‐bound starch synthase gene Wx. NF‐YC12 and bHLH144 maintain NF‐YB1 stability from the degradation mediated by ubiquitin/26S proteasome, while NF‐YB1 directly binds to the ‘G‐box’ domain of Wx promoter and activates Wx transcription, hence to regulate rice grain quality. Finally, we revealed a novel grain quality regulatory pathway controlled by NF‐YB1‐YC12‐bHLH144 complex, which has great potential for rice genetic improvement.