Dof5.6/HCA2, a Dof Transcription Factor Gene, Regulates Interfascicular Cambium Formation and Vascular Tissue Development in Arabidopsis
Dof5.6/HCA2, a Dof Transcription Factor Gene, Regulates Interfascicular Cambium Formation and Vascular Tissue Development in Arabidopsis
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DOI：
10.1105/tpc.108.064139
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发表时间：
2009-11-01
期刊：
影响因子：
11.6
通讯作者：
Qu, Li-Jia
中科院分区：
文献类型：
--
作者：
Guo, Yong;Qin, Genji;Qu, Li-Jia
维管形成层是次生木质部和次生韧皮部的来源，是一种侧面分生组织，但其形成和发育的分子机制尚不清楚。在这里，我们报道了一个拟南芥功能获得突变体的特征，其形成层活性显著增加，称为高形成层活性2 （hca2）。由于束间形成层的早熟形成及其随后的细胞分裂，hca2突变体在花序茎中没有替代维管束/纤维的组织。这种表型是由HCA2的表达升高引起的，HCA2编码一个与一指转录因子Dof5.6结合的核定位DNA。Dof5.6/HCA2在所有器官的脉管系统中优先表达，特别是在花序茎的形成层、韧皮部和束间薄壁细胞中。显性阴性分析进一步表明，HCA2活性的普遍抑制和原位抑制都会导致花序茎束间形成层的形成和发育受到破坏。深入解剖分析表明，HCA2在花序茎发育的早期阶段促进了束间形成层的形成。本报告表明，转录因子基因HCA2参与拟南芥束间形成层形成和维管组织发育的调控。
Vascular cambium, a type of lateral meristem, is the source of secondary xylem and secondary phloem, but little is known about the molecular mechanisms of its formation and development. Here, we report the characterization of an Arabidopsis thaliana gain-of-function mutant with dramatically increased cambial activity, designated high cambial activity2 (hca2). The hca2 mutant has no alternative organization of the vascular bundles/fibers in inflorescence stems, due to precocious formation of interfascicular cambium and its subsequent cell division. The phenotype results from elevated expression of HCA2, which encodes a nuclear-localized DNA binding with one finger (Dof) transcription factor Dof5.6. Dof5.6/HCA2 is preferentially expressed in the vasculature of all the organs, particularly in the cambium, phloem, and interfascicular parenchyma cells of inflorescence stems. Dominant-negative analysis further demonstrated that both ubiquitous and in situ repression of HCA2 activity led to disruption of interfascicular cambium formation and development in inflorescence stems. In-depth anatomical analysis showed that HCA2 promotes interfascicular cambium formation at a very early stage of inflorescence stem development. This report demonstrates that a transcription factor gene, HCA2, is involved in regulation of interfascicular cambium formation and vascular tissue development in Arabidopsis.