Key Proliferative Activity in the Junction between the Leaf Blade and Leaf Petiole of Arabidopsis
Key Proliferative Activity in the Junction between the Leaf Blade and Leaf Petiole of Arabidopsis
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DOI：
10.1104/pp.111.185066
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发表时间：
2011-11-01
期刊：
影响因子：
7.4
通讯作者：
Tsukaya, Hirokazu
中科院分区：
文献类型：
--
作者：
Ichihashi, Yasunori;Kawade, Kensuke;Tsukaya, Hirokazu
叶子是植物器官发生中最重要、最基本的单位。虽然叶片的基本形态被清楚地分为叶片和叶柄，但目前还没有研究揭示它们是如何从叶原基中分化出来的。采用分子标记和克隆分析相结合的方法，详细分析了拟南芥叶片原基有丝分裂活性的时空格局。我们发现，在杆状的早期叶原基出现后，增殖区在短时间内建立起来；它在空间上与茎尖分生组织分离，位于叶片和叶柄之间的连接处，产生叶片细胞和叶柄细胞。叶片原基中的这个增殖区域以ANGUSTIFOLIA3 （AN3）启动子的活性为标志，并且似乎被划分为几个空间区：CYCLIN D4的活性；2启动子和SPATULA增强子特异性标记部分。对an3和叶柄上叶片突变的详细分析进一步支持了叶片和叶柄的器官发生严重依赖于叶片原基增殖区域的正确空间调控的观点。因此，叶片原基的增殖区是空间分化的，同时供应叶片和叶柄细胞。
Leaves are the most important, fundamental units of organogenesis in plants. Although the basic form of a leaf is clearly divided into the leaf blade and leaf petiole, no study has yet revealed how these are differentiated from a leaf primordium. We analyzed the spatiotemporal pattern of mitotic activity in leaf primordia of Arabidopsis (Arabidopsis thaliana) in detail using molecular markers in combination with clonal analysis. We found that the proliferative zone is established after a short interval following the occurrence of a rod-shaped early leaf primordium; it is separated spatially from the shoot apical meristem and seen at the junction region between the leaf blade and leaf petiole and produces both leaf-blade and leaf-petiole cells. This proliferative region in leaf primordia is marked by activity of the ANGUSTIFOLIA3 (AN3) promoter as a whole and seems to be differentiated into several spatial compartments: activities of the CYCLIN D4;2 promoter and SPATULA enhancer mark parts of it specifically. Detailed analyses of the an3 and blade-on-petiole mutations further support the idea that organogenesis of the leaf blade and leaf petiole is critically dependent on the correct spatial regulation of the proliferative region of leaf primordia. Thus, the proliferative zone of leaf primordia is spatially differentiated and supplies both the leaf-blade and leaf-petiole cells.