title: The rice ALS3 encoding a novel pentatricopeptide repeat protein is required for chloroplast development and seedling growth.
abstract: BACKGROUND
  Pentatricopeptide repeat (PPR) proteins play essential roles in modulating the expression of organelle genes and have expanded greatly in higher plants. However, molecular mechanisms of most rice PPR genes remain unclear.
  
  
  RESULTS
  In this study, a new rice PPR mutant, asl3 (albino seedling lethality3) exhibits an albino lethal phenotype at the seedling stage. This albino phenotype was associated with altered photosynthetic-pigment and chloroplast development. Map-based cloning showed that ASL3 encodes a novel rice PPR protein with 10 tandem PPR motifs, which localizes to the chloroplast. ASL3 showed tissue-specific expression, as it was highly expressed in the chlorenchyma, but expressed at much lower levels in roots and panicles. RNAi of ASL3 confirmed that ASL3 plays an essential role in the early development and chloroplast development in rice. Moreover, expression analysis revealed that the asl3 mutation severely affected the transcriptional levels of important genes associated with plastid translation machinery and photosynthesis, which may impair photosynthesis and finally led to the seedling death in asl3 mutant. These results evidenced the important role of ASL3 in the early development of rice, especially chloroplast development.
  
  
  CONCLUSIONS
  The ASL3 gene encoded a novel chloroplast-targeted PPR protein with 10 tandem PPR motifs in rice. Disruption of the ASL3 would lead to a defective chloroplast and seedling lethality, and affected expression levels of genes associated with chloroplast development and photosynthesis at early leaf stage of rice.
authors: Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234 China.
authors: Dongzhi
authors: D
authors: Lin
authors: Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234 China ; Present address: Institute of Genetics and Developmental Biology Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101 China.
authors: Xiaodi
authors: X
authors: Gong
authors: Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234 China.
authors: Quan
authors: Q
authors: Jiang
authors: Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234 China.
authors: Kailun
authors: K
authors: Zheng
authors: Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234 China ; Present address: Agricultural Faculty, Hokkaido University, Sappro, 060-0817 Japan.
authors: Hua
authors: H
authors: Zhou
authors: Institute of Crop Science, National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, 10081 China.
authors: Jianlong
authors: J
authors: Xu
authors: Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032 China.
authors: Sheng
authors: S
authors: Teng
authors: Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234 China.
authors: Yanjun
authors: Y
authors: Dong
keywords: Albino; Chloroplast development; Lethality; Pentatricopeptide repeat (PPR) proteins; Rice