title: OsNAP connects abscisic acid and leaf senescence by fine-tuning abscisic acid biosynthesis and directly targeting senescence-associated genes in rice.
abstract: It has long been established that premature leaf senescence negatively impacts the yield stability of rice, but the underlying molecular mechanism driving this relationship remains largely unknown. Here, we identified a dominant premature leaf senescence mutant, prematurely senile 1 (ps1-D). PS1 encodes a plant-specific NAC (no apical meristem, Arabidopsis ATAF1/2, and cup-shaped cotyledon2) transcriptional activator, Oryza sativa NAC-like, activated by apetala3/pistillata (OsNAP). Overexpression of OsNAP significantly promoted senescence, whereas knockdown of OsNAP produced a marked delay of senescence, confirming the role of this gene in the development of rice senescence. OsNAP expression was tightly linked with the onset of leaf senescence in an age-dependent manner. Similarly, ChIP-PCR and yeast one-hybrid assays demonstrated that OsNAP positively regulates leaf senescence by directly targeting genes related to chlorophyll degradation and nutrient transport and other genes associated with senescence, suggesting that OsNAP is an ideal marker of senescence onset in rice. Further analysis determined that OsNAP is induced specifically by abscisic acid (ABA), whereas its expression is repressed in both aba1 and aba2, two ABA biosynthetic mutants. Moreover, ABA content is reduced significantly in ps1-D mutants, indicating a feedback repression of OsNAP on ABA biosynthesis. Our data suggest that OsNAP serves as an important link between ABA and leaf senescence. Additionally, reduced OsNAP expression leads to delayed leaf senescence and an extended grain-filling period, resulting in a 6.3% and 10.3% increase in the grain yield of two independent representative RNAi lines, respectively. Thus, fine-tuning OsNAP expression should be a useful strategy for improving rice yield in the future.
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China; and.
authors.forename: Chengzhen
authors.initials: C
authors.lastname: Liang
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;
authors.forename: Yiqin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;
authors.forename: Yana
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;
authors.forename: Jiuyou
authors.initials: J
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;
authors.forename: Bin
authors.initials: B
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;
authors.forename: Linchuan
authors.initials: L
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;
authors.forename: Shujun
authors.initials: S
authors.lastname: Ou
authors.affiliation: School of Agriculture and Food Science, Zhejiang Agricultural and Forestry University, Hangzhou 311300, China.
authors.forename: Hongkai
authors.initials: H
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;
authors.forename: Jinfang
authors.initials: J
authors.lastname: Chu
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; ccchu@genetics.ac.cn.
authors.forename: Chengcai
authors.initials: C
authors.lastname: Chu
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D015536:Down-Regulation; D017343:Genes, Plant; D009154:Mutation; D012275:Oryza / Q000235:genetics / Q000502:physiology*; D018515:Plant Leaves / Q000378:metabolism* / Q000502:physiology; D016133:Polymerase Chain Reaction; D015534:Trans-Activators / Q000378:metabolism
chemical_list: D015534:Trans-Activators; D000040:Abscisic Acid
keywords: hormones; nutrition remobilization; programmed cell death