Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India.
Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India.
Plant Sci. 2019 Sep;286:78-88. doi: 10.1016/j.plantsci.2019.05.022. Epub 2019 Jun 3.
Chloroplastic Cpn60 proteins are type I chaperonins comprising of Cpn60α and Cpn60β subunits. Arabidopsis genome contains six entries in Cpn60 family, out of which two are for Cpn60α subunit and four for Cpn60β subunit. We noted that the cpn60β4 knockout mutant plants (T-DNA insertion salk_064887 line) differed from the wild type Col-0 plants in the developmental programming. cpn60β4 mutant plants showed early seed germination. Radical emergence, hypocotyl emergence and cotyledons opening were faster in cpn60β4 mutant plants than WT. Importantly, cpn60β4 mutant plants showed early-flowering phenotype. The number of flowers and siliques as well as weight of the seeds were higher in cpn60β4 mutant plants as compared to Col-0 plants. These effects were reverted to wild type like growth and developmental patterns when genomic fragment of Arabidopsis encompassing Cpn60β4 gene was complemented in the mutant background. The overexpression of Cpn60β4 gene using CaMV35 promoter in wild type background (OE-Cpn60β4) delayed the floral transition as against wild type plants. The plastid division were affected in cpn60β4 mutant plants compared to Col-0. The results of this study suggest that Cpn60β4 plays important role(s) in chloroplast development and is a key factor in plant growth, development and flowering in Arabidopsis.
质体 Cpn60 蛋白是一种 I 型分子伴侣，由 Cpn60α 和 Cpn60β 亚基组成。拟南芥基因组包含 Cpn60 家族的六个条目，其中两个是 Cpn60α 亚基，四个是 Cpn60β 亚基。我们注意到，cpn60β4 敲除突变体植物（T-DNA 插入 salk_064887 系）在发育编程方面与野生型 Col-0 植物不同。cpn60β4 突变体植物的种子萌发较早。cpn60β4 突变体植物的根、下胚轴和子叶的出现以及子叶的张开速度比 WT 更快。重要的是，cpn60β4 突变体植物表现出早花表型。与 Col-0 植物相比，cpn60β4 突变体植物的花和角果数量以及种子重量更高。当拟南芥包含 Cpn60β4 基因的基因组片段在突变体背景中互补时，这些效应恢复为野生型样的生长和发育模式。使用 CaMV35 启动子在野生型背景下过表达 Cpn60β4 基因（OE-Cpn60β4）延迟了花的转变，而不是野生型植物。与 Col-0 相比，cpn60β4 突变体植物的质体分裂受到影响。这项研究的结果表明，Cpn60β4 在叶绿体发育中发挥重要作用，是拟南芥生长、发育和开花的关键因素。
