Mutation of Oryza sativa CORONATINE INSENSITIVE 1b (OsCOI1b) delays leaf senescence

• Published in: Journal of integrative plant biology Vol. 57; no. 6; pp. 562 - 576
• Main Authors: Lee, Sang-Hwa, Sakuraba, Yasuhito, Lee, Taeyoung, Kim, Kyu-Won, An, Gynheung, Lee, Han Yong, Paek, Nam-Chon
• Format: Journal Article
• Language: English
• Published: China (Republic : 1949- ) Blackwell Publishing Ltd 01.06.2015; Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea%Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 151-741, Korea%Department of Plant Molecular Systems Biotechnology, Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea%Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
• Subjects: Acetates - pharmacology; Cyclopentanes - pharmacology; Darkness; Gene Expression Regulation, Plant - drug effects; Gene Knockout Techniques; Genes, Plant; Genetic Complementation Test; Jasmonic acid; leaf senescence; Mutation - genetics; Oryza - drug effects; Oryza - genetics; Oryza - growth & development; OsCOI1b; Oxylipins - pharmacology; Phenotype; Phylogeny; Plant Growth Regulators - pharmacology; Plant Leaves - drug effects; Plant Leaves - genetics; Plant Leaves - growth & development; Plant Leaves - ultrastructure; Plant Proteins - genetics; Plant Proteins - metabolism; rice; Seeds - drug effects; Seeds - growth & development; Sequence Homology, Nucleic Acid; stay-green; stay-green; OsCOI1b; rice; Jasmonic acid; leaf senescence
• ISSN: 1672-9072; 1744-7909
• DOI: 10.1111/jipb.12276

Jasmonic acid (JA) functions in plant development, including senescence and immunity. Arabidopsis thaliana CORONATINE INSENSITIVE 1 encodes a JA receptor and functions in the JA‐responsive signaling pathway. The Arabidopsis genome harbors a single COI gene, but the rice (Oryza sativa) genome harbors three COI homologs, OsCOI1a, OsCOI1b, and OsCOI2. Thus, it remains unclear whether each OsCOI has distinct, additive, synergistic, or redundant functions in development. Here, we use the oscoi1b‐1 knockout mutants to show that OsCOI1b mainly affects leaf senescence under senescence‐promoting conditions. oscoi1b‐1 mutants stayed green during dark‐induced and natural senescence, with substantial retention of chlorophylls and photosynthetic capacity. Furthermore, several senescence‐associated genes were downregulated in oscoi1b‐1 mutants, including homologs of Arabidopsis thaliana ETHYLENE INSENSITIVE 3 and ORESARA 1, important regulators of leaf senescence. These results suggest that crosstalk between JA signaling and ethylene signaling affects leaf senescence. The Arabidopsis coi1‐1 plants containing 35S:OsCOI1a or 35S:OsCOI1b rescued the delayed leaf senescence during dark incubation, suggesting that both OsCOI1a and OsCOI1b are required for promoting leaf senescence in rice. oscoi1b‐1 mutants showed significant decreases in spikelet fertility and grain weight, leading to severe reduction of grain yield, indicating that OsCOI1‐mediated JA signaling affects spikelet fertility and grain filling.