title: Lethal albinic seedling, encoding a threonyl-tRNA synthetase, is involved in development of plastid protein synthesis system in rice.
abstract: An albinic rice is caused by mutation of threonyl-tRNA synthetase, which is essential for plant development by stabilizing of NEP and PEP gene expressions and chloroplast protein synthesis. Chloroplast biogenesis and development depend on complex genetic mechanisms. Apart from their function in translation, aminoacyl-tRNA synthetases (aaRSs) play additional role in gene expression regulation, RNA splicing, and cytokine activity. However, their detailed functions in plant development are still poorly understood. We isolated a lethal albinic seedling (las) mutant in rice. Physiological and ultrastructural analysis of las mutant plants revealed weak chlorophyll fluorescence, negligible chlorophyll accumulation, and defective thylakoid membrane development. By map based cloning we determined that the LAS allele gene encodes threonyl-tRNA synthetase (ThrRS). LAS was constitutively expressed with relatively high level in leaves. NEP-dependent gene transcripts accumulated in the developing chloroplasts, while PEP-dependent transcripts were reduced in the las mutant. This result indicated that PEP activity was impaired. Chloroplast-encoded protein levels were sharply reduced in the las mutant. Biogenesis of chloroplast rRNAs (16S and 23S rRNA) was arrested, leading to impaired translation and protein synthesis. Together, our findings indicated that LAS is essential not only for chloroplast development by stabilizing the NEP and PEP gene expression, but also for protein synthesis and construction of the ribosome system in rice chloroplasts.
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Yuan-Yan
authors.initials: YY
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Hao
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Yi-Hua
authors.initials: YH
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Chun-Ming
authors.initials: CM
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Yun-Long
authors.initials: YL
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Wu-Hua
authors.initials: WH
authors.lastname: Long
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Di
authors.initials: D
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China. wanjm@njau.edu.cn.|National Key Facility for Crop Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China. wanjm@njau.edu.cn.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Wan
mesh_terms: D060365:Chloroplast Proteins / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D017343:Genes, Plant / Q000235:genetics; D009154:Mutation; D012275:Oryza / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D018087:Plastids / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D013914:Threonine-tRNA Ligase / Q000235:genetics / Q000378:metabolism*
chemical_list: D060365:Chloroplast Proteins; D010940:Plant Proteins; D013914:Threonine-tRNA Ligase
keywords: Chloroplast development; Chloroplast protein synthesis; Oryza sativa; Plastid-encoded RNA polymerase