RLS3, a protein with AAA＋ domain localized in chloroplast, sustains leaf longevity in rice

• Published in: Journal of integrative plant biology 2016-12, Vol.58 (12), p.971-982
• Main Authors: Lin, Yanhui, Tan, Lubin, Zhao, Lei, Sun, Xianyou, Sun, Chuanqing
• Format: Article
• Language: English
• Subjects: AAA+ domain; Chloroplasts - metabolism; Chloroplasts - ultrastructure; Cloning, Molecular; Darkness; Gene Expression Regulation, Plant; Genes, Plant; Mesophyll Cells - cytology; Mesophyll Cells - metabolism; Mesophyll Cells - ultrastructure; Mutation - genetics; Oryza - genetics; Oryza - physiology; Oryza - ultrastructure; Phenotype; Photosynthesis; Phylogeny; Plant Leaves - physiology; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified; Protein Domains; Protein Transport; rapid leaf senescence; rice; RLS3; Sequence Homology, Amino Acid; Subcellular Fractions - metabolism
• ISSN: 1672-9072; 1744-7909
• DOI: 10.1111/jipb.12487

Leaf senescence plays an important role in crop developmental processes that dramatically affect crop yield and grain quality. The genetic regulation of leaf senescence is complex, involving many metabolic and signaling pathways. Here, we identified a rapid leaf senescence 3 （rls3） mutant that displayed accelerated leaf senescence, shorter plant height and panicle length, and lower seed set rate than the wild type. Map-based cloning revealed that RLS3 encodes a protein with AAA＋ domain, localizing it to chloroplasts. Sequence analysis found that the rls3 8ene had a single-nucleotide substitution （G--~A） at the splice site of the Ioth intron/11th exon, resulting in the cleavage of the first nucleotide in 11th exon and premature termination of P, LS3 protein translation. Using transmission electron microscope, the chloroplasts of the rls3 mutant were observed to degrade much faster than those of the wild type. The investigation of the leaf senescence process under dark incubation conditions further revealed that the rls3 mutant displayed rapid leaf senescence. Thus, the RLS3 gene plays key roles in sustaining the normal growth of rice, while loss of function in RLS3 leads to rapid leaf senescence. The identification of RLS3 will be helpful to elucidate the mechanisms involved in leaf senescence in rice.