Enhanced cytokinin degradation in leaf primordia of transgenic Arabidopsis plants reduces leaf size and shoot organ primordia formation
Enhanced cytokinin degradation in leaf primordia of transgenic Arabidopsis plants reduces leaf size and shoot organ primordia formation
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DOI：
10.1016/j.jplph.2011.03.003
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发表时间：
2011-08-15
影响因子：
4.3
通讯作者：
Werner, Tomas
中科院分区：
文献类型：
--
作者：
Holst, Kerstin;Schmuelling, Thomas;Werner, Tomas
植物激素细胞分裂素是控制细胞分裂和分化的关键形态发生因子，从而控制植物生活史中器官的形成和生长速率。为了探讨细胞分裂素在叶原基形成的初始阶段的相关性及其对随后的叶发育的影响，我们增加了细胞分裂素的降解在幼苗器官原基的拟南芥通过表达细胞分裂素氧化酶/脱氢酶（CKX）基因控制下的AINTEGUMENTA（ANT）启动子。ANT：CKX 3植物中的最终叶大小减小至与野生型大小的27%相似，并且表皮细胞的数目减小至与野生型的12%相似。运动学分析表明，细胞增殖停止较早，细胞扩增加速ANT：CKX 3叶，表明细胞分裂素控制的增殖期的持续时间延迟细胞分化的发病。细胞数量的减少部分地被增加的细胞扩增所补偿。有趣的是，ANT：CKX 3叶细胞比35 S：CKX 3叶细胞大约60%，表明细胞分裂素在细胞扩增过程中也具有重要功能。此外，ANT：CKX 3表达显著降低了营养芽和生殖芽顶端分生组织分别启动新叶和花形成的能力。因此，我们推测，在器官原基中的细胞分裂素含量是重要的调节活动的拍摄分生组织在一个非自主的方式。(C)2011年Elsevier GmbH。All rights reserved.
The plant hormone cytokinin is a key morphogenic factor controlling cell division and differentiation, and thus the formation and growth rate of organs during a plant's life cycle. In order to explore the relevance of cytokinin during the initial phase of leaf primordia formation and its impact on subsequent leaf development, we increased cytokinin degradation in young shoot organ primordia of Arabidopsis thaliana by expressing a cytokinin oxidase/dehydrogenase (CKX)gene under control of the AINTEGUMENTA (ANT) promoter. The final leaf size in ANT:CKX3 plants was reduced to similar to 27% of the wild-type size and the number of epidermal cells was reduced to similar to 12% of the wild type. Kinematic analysis revealed that cell proliferation ceased earlier and cell expansion was accelerated in ANT:CKX3 leaves, demonstrating that cytokinin controls the duration of the proliferation phase by delaying the onset of cell differentiation. The reduction of the cell number was partially compensated by an increased cell expansion. Interestingly, ANT:CKX3 leaf cells became about 60% larger than those of 35S:CKX3 leaves, indicating that cytokinin has an important function during cell expansion as well. Furthermore, ANT:CKX3 expression significantly reduced the capacity of both the vegetative as well as the generative shoot apical meristem to initiate the formation of new leaves and flowers, respectively. We therefore hypothesize that the cytokinin content in organ primordia is important for regulating the activity of the shoot meristem in a non-autonomous fashion. (C) 2011 Elsevier GmbH. All rights reserved.