title: ALT1, a Snf2 family chromatin remodeling ATPase, negatively regulates alkaline tolerance through enhanced defense against oxidative stress in rice.
abstract: Alkaline salt stress adversely affects rice growth, productivity and grain quality. However, the mechanism underlying this process remains elusive. We characterized here an alkaline tolerant mutant, alt1 in rice. Map-based cloning revealed that alt1 harbors a mutation in a chromatin remodeling ATPase gene. ALT1-RNAi transgenic plants under different genetic background mimicked the alt1 phenotype, exhibiting tolerance to alkaline stress in a transcript dosage-dependent manner. The predicted ALT1 protein belonged to the Ris1 subgroup of the Snf2 family and was localized in the nucleus, and transcription of ALT1 was transiently suppressed after alkaline treatment. Although the absorption of several metal ions maintained well in the mutant under alkaline stress, expression level of the genes involved in metal ions homeostasis was not altered in the alt1 mutant. Classification of differentially expressed abiotic stress related genes, as revealed by microarray analysis, found that the majority (50/78) were involved in ROS production, ROS scavenging, and DNA repair. This finding was further confirmed by that alt1 exhibited lower levels of H2O2 under alkaline stress and tolerance to methyl viologen treatment. Taken together, these results suggest that ALT1 negatively functions in alkaline tolerance mainly through the defense against oxidative damage, and provide a potential two-step strategy for improving the tolerance of rice plants to alkaline stress.
authors.affiliation: State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Mingxin
authors.initials: M
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Ruci
authors.initials: R
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Hua
authors.affiliation: State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Yueming
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Shanguo
authors.initials: S
authors.lastname: Yao
mesh_terms: D000251:Adenosine Triphosphatases / Q000096:biosynthesis*; D002843:Chromatin / Q000235:genetics; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D046228:Microarray Analysis; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D018384:Oxidative Stress / Q000235:genetics*; D010940:Plant Proteins / Q000096:biosynthesis*; D030821:Plants, Genetically Modified; D055051:Salt-Tolerant Plants / Q000235:genetics / Q000502:physiology; D012492:Salts / Q000008:administration & dosage; D036226:Seedlings / Q000187:drug effects / Q000235:genetics; D013312:Stress, Physiological / Q000235:genetics
chemical_list: D002843:Chromatin; D010940:Plant Proteins; D012492:Salts; D006861:Hydrogen Peroxide; C000600068:ALT1 protein, rice; D000251:Adenosine Triphosphatases; D005978:Glutathione