ALT1, a Snf2 family chromatin remodeling ATPase, negatively regulates alkaline tolerance through enhanced defense against oxidative stress in rice

• Published in: PloS one Vol. 9; no. 12; p. e112515
• Main Authors: Guo, Mingxin, Wang, Ruci, Wang, Juan, Hua, Kai, Wang, Yueming, Liu, Xiaoqiang, Yao, Shanguo
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 04.12.2014; Public Library of Science (PLoS)
• Subjects: Abiotic stress; Adenosine triphosphatase; Adenosine Triphosphatases - biosynthesis; Arabidopsis; ATPases; Barley; Biology and Life Sciences; Chromatin; Chromatin - genetics; Chromatin Assembly and Disassembly - drug effects; Chromatin Assembly and Disassembly - genetics; Chromatin remodeling; Cloning; Damage tolerance; Deoxyribonucleic acid; Developmental biology; DNA; DNA microarrays; DNA repair; Drought; Enzymes; Fluorides; Gene expression; Gene Expression Regulation, Plant - drug effects; Genes; Genomics; Glutathione - metabolism; Glycine max; Grain; Homeostasis; Hydrogen peroxide; Hydrogen Peroxide - metabolism; Iron; Kinases; Laboratories; Metal ions; Methyl viologen; Microarray Analysis; Mutation; Oryza; Oryza - genetics; Oryza - growth & development; Oxidative stress; Oxidative Stress - genetics; Phenotypes; Plant mitochondria; Plant Proteins - biosynthesis; Plants, Genetically Modified; Proteins; Reactive oxygen species; Rice; RNA-mediated interference; Salt; Salt-Tolerant Plants - genetics; Salt-Tolerant Plants - physiology; Salts - administration & dosage; Seedlings - drug effects; Seedlings - genetics; Signal transduction; Stress response; Stress, Physiological - genetics; Subgroups; Transcription; Transcription factors; Transgenic plants; Beijing China; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0112515

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.