Rice aleurone layer specific OsNF-YB1 regulates grain filling and endosperm development by interacting with an ERF transcription factor.
Grain yield and quality of rice mainly depend on grain filling and endosperm development. Here we report that a rice NUCLEAR FACTOR Y (NF-Y) transcription factor, OsNF-YB1, is specifically expressed in the aleurone layer of developing endosperm and regulates grain filling and endosperm development. Knockdown of OsNF-YB1 expression by RNAi significantly retarded grain filling, leading to small grains with chalky endosperm as well as altered starch quality. Whereas OsNF-YB1 shows subcellular localization in both the cytosol and the nucleus in roots, it was specifically targeted to the nucleus of aleurone layer cells, which was facilitated by interacting with OsNF-YC proteins preferentially expressed in the aleurone layer. RNA sequencing analysis revealed that genes related to membrane transport and ATP biosynthesis were enriched in the down-regulated category in OsNF-YB1 RNAi plants, which is consistent with the crucial role of OsNF-YB1 in rice grain filling and endosperm development. Identification of the genome-wide targets of OsNF-YB1 by ChIP sequencing showed that OsNF-YB1 directly regulates genes involved in the transport of nutrients such as sugar and amino acids. Interestingly, different from the binding sites reported for other NF-Y complexes, the GCC box, the binding motif of ERF transcription factors, was enriched in the binding peaks of OsNF-YB1. Indeed, further analyses confirmed the interaction of OsERF#115 with OsNF-YB1, and OsERF#115 directly binds to the GCC box. It is proposed that OsNF-YB1 specifically regulate the transcription of downstream genes during rice endosperm development by forming protein complexes consisting of OsNF-YB1, OsNF-YC and ERF, providing informative insights into the molecular functional mechanisms of the NF-Y factor.
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, 200032 Shanghai, China.
Jing-Jing
JJ
Xu
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, 200032 Shanghai, China.
Xiao-Fan
XF
Zhang
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, 200032 Shanghai, China hwxue@sibs.ac.cn.
Hong-Wei
HW
Xue
D056625:Endosperm / Q000254:growth & development / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D055785:Gene Knockdown Techniques; D017403:In Situ Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000254:growth & development / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism / Q000502:physiology*; D018517:Plant Roots / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012639:Seeds / Q000254:growth & development / Q000378:metabolism*; D017423:Sequence Analysis, RNA; D014157:Transcription Factors / Q000502:physiology*; D020798:Two-Hybrid System Techniques
D010940:Plant Proteins; D014157:Transcription Factors; C000624173:aleurone
Aleurone layer; ERF; GCC box; OsNF-YB1.; endosperm development; grain filling