Identification of novel meristem factors involved in shoot regeneration through the analysis of temperature-sensitive mutants of Arabidopsis.
Identification of novel meristem factors involved in shoot regeneration through the analysis of temperature-sensitive mutants of Arabidopsis.
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DOI：
10.1111/j.1365-313x.2008.03750.x
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发表时间：
2009-03
期刊：
影响因子：
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通讯作者：
Hiroaki Tamaki;Mineko Konishi;Yasufumi Daimon;M. Aida;M. Tasaka;M. Sugiyama
中科院分区：
文献类型：
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作者：
Hiroaki Tamaki;Mineko Konishi;Yasufumi Daimon;M. Aida;M. Tasaka;M. Sugiyama
植物组织培养中的不定器官发生涉及顶端分生组织的重新形成，因此应该提供关于分生组织基因网络的基本原理的重要信息。我们确定了新形成的茎顶端分生组织（SAM）所需的新的因素，通过根起始缺陷3（rid 3）和根生长缺陷3（rgd 3）温度敏感突变体的拟南芥芽再生的分析。诱导愈伤组织再生芽后，细胞分裂很快停止，然后在表面区域局部重新激活，导致形成密集的细胞土丘，其中不定芽SAM最终构建。rgd 3突变抑制了细胞分裂的再激活，并抑制了杯形子叶1（CUC 1）、CUC 2和茎无分生组织（STM）的表达。相反，rid 3突变导致愈伤组织表面上过度的不受控制的细胞分裂。这与CUC 1表达的增强和扩大密切相关。定位克隆结果表明，RGD 3和RID 3基因分别编码TATA结合蛋白相关因子BTAF 1和WD-40重复序列蛋白。在芽再生的早期阶段，RGD 3在发育中的细胞土丘中表达（如CUC 1），而RID 3在细胞土丘外表达。当RID 3人工过表达时，CUC 1和STM的表达水平显著降低。总之，这些发现表明，CUC-STM途径的RID 3负调控和RGD 3正调控都参与了细胞分裂的适当控制，作为SAM新形成的先决条件。
Adventitious organogenesis in plant tissue culture involves de novo formation of apical meristems and should therefore provide important information about the fundamentals of meristem gene networks. We identified novel factors required for neoformation of the shoot apical meristem (SAM) through an analysis of shoot regeneration in root initiation defective3 (rid3) and root growth defective3 (rgd3) temperature-sensitive mutants of Arabidopsis. After induction of callus to regenerate shoots, cell division soon ceased and was then reactivated locally in the surface region, resulting in formation of mounds of dense cells in which adventitious-bud SAMs were eventually constructed. The rgd3 mutation inhibited reactivation of cell division and suppressed expression of CUP-SHAPED COTYLEDON1 (CUC1), CUC2 and SHOOT MERISTEMLESS (STM). In contrast, the rid3 mutation caused excess ill-controlled cell division on the callus surface. This was intimately related to enhanced and broadened expression of CUC1. Positional cloning revealed that the RGD3 and RID3 genes encode BTAF1 (a kind of TATA-binding protein-associated factor) and an uncharacterized WD-40 repeat protein, respectively. In the early stages of shoot regeneration, RGD3 was expressed (as was CUC1) in the developing cell mounds, whereas RID3 was expressed outside the cell mounds. When RID3 was over-expressed artificially, the expression levels of CUC1 and STM were significantly reduced. Taken together, these findings show that both negative regulation by RID3 and positive regulation by RGD3 of the CUC-STM pathway participate in proper control of cell division as a prerequisite for SAM neoformation.