Gibberellin indirectly promotes chloroplast biogenesis as a means to maintain the chloroplast population of expanded cells
Gibberellin indirectly promotes chloroplast biogenesis as a means to maintain the chloroplast population of expanded cells
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赤霉素间接促进叶绿体生物发生，作为维持扩增细胞叶绿体群体的一种手段
DOI：
10.1111/j.1365-313x.2012.05118.x
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发表时间：
2012-12-01
期刊：
影响因子：
7.2
通讯作者：
Wang, Xiaojing
中科院分区：
文献类型：
--
作者：
Jiang, Xingshan;Li, Heying;Wang, Xiaojing
在植物生长发育过程中，叶绿体的生物合成需要与细胞分裂和细胞扩张协调一致，以获得最佳的光合速率。研究表明赤霉素（gibberellins，GAs）对植物细胞分裂和细胞扩增等重要发育过程具有调节作用。然而，叶绿体生物发生与细胞分裂和细胞扩增之间的关系，以及GA如何协调调节这些过程，仍然知之甚少。在这项研究中，我们发现，叶绿体分裂显着减少GA缺陷突变体的拟南芥（ga 1 -3）和水稻（d18-AD），伴随着几个叶绿体分裂相关基因的表达减少。然而，这两个突变体的叶绿体表现出增加的基粒堆积与各自的野生型植物相比，这表明可能有一个补偿机制连接叶绿体分裂和基粒堆积。时间进程分析表明，GA处理的ga 1 -3叶片中，与细胞扩展相关的基因比与叶绿体分裂和细胞分裂相关的基因更早、更显著地上调，表明GA可能通过影响叶片叶肉细胞扩展而间接促进叶绿体分裂。此外，我们的GA反应信号突变体的细胞和分子分析表明，RGA和GAI是调节GA诱导的叶绿体分裂的主要阻遏物，但其他DELLA蛋白（RGL 1，RGL 2和RGL 3）也发挥作用，在拟南芥中抑制叶绿体分裂。总之，我们的数据表明，GA通过影响双子叶和单子叶植物物种中的DELLA蛋白家族，在控制和协调细胞分裂、细胞扩增和叶绿体生物发生中起着关键作用。
Chloroplast biogenesis needs to be well coordinated with cell division and cell expansion during plant growth and development to achieve optimal photosynthesis rates. Previous studies showed that gibberellins (GAs) regulate many important plant developmental processes, including cell division and cell expansion. However, the relationship between chloroplast biogenesis with cell division and cell expansion, and how GA coordinately regulates these processes, remains poorly understood. In this study, we showed that chloroplast division was significantly reduced in the GA-deficient mutants of Arabidopsis (ga1-3) and Oryza sativa (d18-AD), accompanied by the reduced expression of several chloroplast division-related genes. However, the chloroplasts of both mutants exhibited increased grana stacking compared with their respective wild-type plants, suggesting that there might be a compensation mechanism linking chloroplast division and grana stacking. A time-course analysis showed that cell expansion-related genes tended to be upregulated earlier and more significantly than the genes related to chloroplast division and cell division in GA-treated ga1-3 leaves, suggesting the possibility that GA may promote chloroplast division indirectly through impacting leaf mesophyll cell expansion. Furthermore, our cellular and molecular analysis of the GA-response signaling mutants suggest that RGA and GAI are the major repressors regulating GA-induced chloroplast division, but other DELLA proteins (RGL1, RGL2 and RGL3) also play a role in repressing chloroplast division in Arabidopsis. Taken together, our data show that GA plays a critical role in controlling and coordinating cell division, cell expansion and chloroplast biogenesis through influencing the DELLA protein family in both dicot and monocot plant species.