Wang Wen-Juan, Zheng Kai-Lun, Gong Xiao-Di, Xu Jian-Long, Huang Ji-Rong, Lin Dong-Zhi, Dong Yan-Jun
Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China.
Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China; Institute of Genetics and Developmental Biology Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 10010, China.
Plant Sci. 2017 Jun;259:1-11. doi: 10.1016/j.plantsci.2017.02.007. Epub 2017 Feb 27.
Plastid ribosome proteins (PRPs) are important components for chloroplast biogenesis and early chloroplast development. Although it has been known that chloroplast ribosomes are similar to bacterial ones, the precise molecular function of ribosomal proteins remains to be elucidated in rice. Here, we identified a novel rice mutant, designated tcd11 (thermo-sensitive chlorophyll-deficient mutant 11), characterized by the albino phenotype until it died at 20°C, while displaying normal phenotype at 32°C. The alteration of leaf color in tcd11 mutants was aligned with chlorophyll (Chl) content and chloroplast development. The map-based cloning and molecular complementation showed that TCD11 encodes the ribosomal small subunit protein S6 in chloroplasts (RPS6). TCD11 was abundantly expressed in leaves, suggesting its different expressions in tissues. In addition, the disruption of TCD11 greatly reduced the transcript levels of certain chloroplasts-associated genes and prevented the assembly of ribosome in chloroplasts at low temperature (20°C), whereas they recovered to nearly normal levels at high temperature (32°C). Thus, our data indicate that TCD11 plays an important role in chloroplast development at low temperature. Upon our knowledge, the observations from this study provide a first glimpse into the importance of RPS6 function in rice chloroplast development.
质体核糖体蛋白（PRPs）是叶绿体生物发生和早期叶绿体发育的重要组成部分。尽管已知叶绿体核糖体与细菌核糖体相似，但核糖体蛋白在水稻中的精确分子功能仍有待阐明。在此，我们鉴定了一个新的水稻突变体，命名为tcd11（温度敏感型叶绿素缺乏突变体11），其特征是在20°C时表现为白化表型直至死亡，而在32°C时表现正常表型。tcd11突变体叶片颜色的变化与叶绿素（Chl）含量和叶绿体发育一致。基于图谱的克隆和分子互补表明，TCD11编码叶绿体核糖体小亚基蛋白S6（RPS6）。TCD11在叶片中大量表达，表明其在不同组织中的表达存在差异。此外，TCD11的缺失极大地降低了某些叶绿体相关基因的转录水平，并在低温（20°C）下阻止了叶绿体中核糖体的组装，而在高温（32°C）下它们恢复到接近正常水平。因此，我们的数据表明TCD11在低温下的叶绿体发育中起重要作用。据我们所知，本研究的观察结果首次揭示了RPS6功能在水稻叶绿体发育中的重要性。
