Promotion of chloroplast proliferation upon enhanced post-mitotic cell expansion in leaves.
Promotion of chloroplast proliferation upon enhanced post-mitotic cell expansion in leaves.
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DOI：
10.1186/1471-2229-13-143
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发表时间：
2013-09-28
影响因子：
5.3
通讯作者：
Tsukaya H
中科院分区：
文献类型：
--
作者：
Kawade K;Horiguchi G;Ishikawa N;Hirai MY;Tsukaya H
叶是决定器官；因此，精确控制细胞增殖和有丝分裂后细胞扩增对其生长至关重要。细胞增殖的缺陷常常引起叶片中有丝分裂后细胞扩增的增强。这种现象被称为“补偿”。来自代偿研究的几条证据表明，在叶片发育过程中，细胞增殖和有丝分裂后细胞扩增是协调调节的。因此，叶片生长的补偿机制引起了人们的广泛关注。然而，我们对亚细胞水平代偿的理解仍然有限，因为代偿的研究主要集中在细胞水平的表型上。适当的叶片生长需要与细胞水平变化相关的亚细胞成分的定量控制。为了深入了解代偿的亚细胞方面，我们研究了代偿系中细胞面积和每个细胞叶绿体数量之间众所周知的关系，并询问叶绿体增殖是否受到代偿诱导的调节。首次建立了一种简便、可靠的叶绿体原位观察方法。利用这种方法，我们分析了已知具有典型补偿特征的拟南芥突变体fugu5和angustifolia3 (an3)，以及转基因系kip相关蛋白2过表达物KRP2 OE。我们在这里发现，这些系的表皮下栅栏组织的每细胞叶绿体数量增加。我们分析了四倍体野生型、fugu5、an3和KRP2 OE，发现细胞面积本身是决定叶绿体增殖活性的关键参数，而不是核倍性。特别是在an3的情况下，我们发现叶绿体增殖的促进依赖于有丝分裂后细胞扩增的增强。在此过程中，叶绿体增殖相关基因的表达水平与野生型相似或低于野生型。本研究表明，叶绿体增殖在代偿系中得到促进。这种对叶绿体增殖的促进是对an3细胞分裂后细胞面积增加的反应。叶绿体增殖相关基因的表达在包括an3在内的代偿性株系中没有得到促进，这表明在这些株系中叶绿体增殖的调节机制尚不清楚。
Leaves are determinate organs; hence, precise control of cell proliferation and post-mitotic cell expansion is essential for their growth. A defect in cell proliferation often triggers enhanced post-mitotic cell expansion in leaves. This phenomenon is referred to as ‘compensation’. Several lines of evidence from studies on compensation have shown that cell proliferation and post-mitotic cell expansion are coordinately regulated during leaf development. Therefore, compensation has attracted much attention to the mechanisms for leaf growth. However, our understanding of compensation at the subcellular level remains limited because studies of compensation have focused mainly on cellular-level phenotypes. Proper leaf growth requires quantitative control of subcellular components in association with cellular-level changes. To gain insight into the subcellular aspect of compensation, we investigated the well-known relationship between cell area and chloroplast number per cell in compensation-exhibiting lines, and asked whether chloroplast proliferation is modulated in response to the induction of compensation. We first established a convenient and reliable method for observation of chloroplasts in situ. Using this method, we analyzed Arabidopsis thaliana mutants fugu5 and angustifolia3 (an3), and a transgenic line KIP-RELATED PROTEIN2 overexpressor (KRP2 OE), which are known to exhibit typical features of compensation. We here showed that chloroplast number per cell increased in the subepidermal palisade tissue of these lines. We analyzed tetraploidized wild type, fugu5, an3 and KRP2 OE, and found that cell area itself, but not nuclear ploidy, is a key parameter that determines the activity of chloroplast proliferation. In particular, in the case of an3, we uncovered that promotion of chloroplast proliferation depends on the enhanced post-mitotic cell expansion. The expression levels of chloroplast proliferation-related genes are similar to or lower than that in the wild type during this process. This study demonstrates that chloroplast proliferation is promoted in compensation-exhibiting lines. This promotion of chloroplast proliferation takes place in response to cell-area increase in post-mitotic phase in an3. The expression of chloroplast proliferation-related genes were not promoted in compensation-exhibiting lines including an3, arguing that an as-yet-unknown mechanism is responsible for modulation of chloroplast proliferation in these lines.
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影响因子：
4.9
作者：
Kozuka, T;Horiguchi, G;Tsukaya, H
通讯作者：
Tsukaya, H
影响因子：
7.4
作者：
Ichihashi, Yasunori;Kawade, Kensuke;Tsukaya, Hirokazu
通讯作者：
Tsukaya, Hirokazu
影响因子：
11.6
作者：
Breuer, Christian;Stacey, Nicola J.;Sugimoto-Shirasua, Keiko
通讯作者：
Sugimoto-Shirasua, Keiko
影响因子：
11.6
作者：
Osteryoung, KW;Stokes, KD;Lee, WY
通讯作者：
Lee, WY
影响因子：
7.4
作者：
Barroco, Rosa Maria;Peres, Adrian;Frankard, Valerie
通讯作者：
Frankard, Valerie