Regulation of root hair initiation and expansin gene expression in Arabidopsis
Regulation of root hair initiation and expansin gene expression in Arabidopsis
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DOI：
10.1105/tpc.006437
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发表时间：
2002-12-01
期刊：
影响因子：
11.6
通讯作者：
Cosgrove, DJ
中科院分区：
文献类型：
--
作者：
Cho, HT;Cosgrove, DJ
两个拟南芥expansin基因（AtEXP 7和AtEXP 18）的表达是紧密相连的根毛起始，因此，这些基因的调控进行了研究，以阐明如何发展，激素和环境因素编排根毛的形成。外源乙烯和生长素，以及从介质中分离的根，刺激根毛的形成和这些expansin基因的表达。外源生长素和离根对根毛形成的影响需要乙烯信号通路的参与。相反，阻断内源性乙烯途径，无论是通过基因突变或化学抑制剂，不影响正常的根毛形成和expansin基因表达。这些结果表明，根毛形成的正常发育途径（即，不受外部刺激诱导）不依赖于乙烯途径。扩展蛋白基因的启动子分析表明，相同的启动子元件，决定细胞特异性也决定诱导乙烯，生长素，和根分离。我们的研究表明，两个独特的信号通路，一个发展和其他环境/激素，收敛到调制根毛的启动和其特定的expansin基因集的表达。
The expression of two Arabidopsis expansin genes (AtEXP7 and AtEXP18) is tightly linked to root hair initiation; thus, the regulation of these genes was studied to elucidate how developmental, hormonal, and environmental factors orchestrate root hair formation. Exogenous ethylene and auxin, as well as separation of the root from the medium, stimulated root hair formation and the expression of these expansin genes. The effects of exogenous auxin and root separation on root hair formation required the ethylene signaling pathway. By contrast, blocking the endogenous ethylene pathway, either by genetic mutations or by a chemical inhibitor, did not affect normal root hair formation and expansin gene expression. These results indicate that the normal developmental pathway for root hair formation (i.e., not induced by external stimuli) is independent of the ethylene pathway. Promoter analyses of the expansin genes show that the same promoter elements that determine cell specificity also determine inducibility by ethylene, auxin, and root separation. Our study suggests that two distinctive signaling pathways, one developmental and the other environmental/hormonal, converge to modulate the initiation of the root hair and the expression of its specific expansin gene set.