A molecular mechanism unique to hydrotropism in roots
A molecular mechanism unique to hydrotropism in roots
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DOI：
10.1016/j.plantsci.2009.06.009
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发表时间：
2009-10
期刊：
影响因子：
5.2
通讯作者：
Y. Miyazawa;Yoshiei Ito;Teppei Moriwaki;A. Kobayashi;N. Fujii;Hideyuki Takahashi
中科院分区：
文献类型：
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作者：
Y. Miyazawa;Yoshiei Ito;Teppei Moriwaki;A. Kobayashi;N. Fujii;Hideyuki Takahashi
植物在自然界中是无柄的，并且必须对各种环境线索做出反应以调节其生长方向。根系向水性是植物对水分梯度的一种响应，在植物抗旱性中起着重要作用。尽管如此，根的向水性的基本过程直到最近仍然不清楚，因为向重力性的干扰作用。为了阐明根的向水性，我们分离和分析了两个拟南芥突变体，水-kussei（米兹）1和2，有异常的向水性反应，但正常的重力反应。MIZ 1编码一种功能未知的蛋白质，其C-末端具有保守结构域。MIZ 2编码ADP核糖基化因子型G蛋白的鸟嘌呤核苷酸交换因子，已被鉴定为Gnom。这些发现表明，根具有必要的分子机制，向水性，但独立的向重力性。其中一种机制涉及到根中向水性所特有的囊泡运输。本文就植物根系向水性化的分子机制以及MIZ 1和MIZ 2的作用进行综述。
Plants are sessile in nature and must respond to various environmental cues to regulate their growth orientation. Root hydrotropism, a response to moisture gradients, has been considered to play an important role in drought avoidance. Nonetheless, the processes underlying hydrotropism in roots have remained obscure until recently because of the interfering effect of gravitropism. To shed light on root hydrotropism, we isolated and analyzed two Arabidopsis mutants, mizu-kussei (miz) 1 and 2, that have abnormal hydrotropic responses but normal responses to gravity. MIZ1 encodes a protein of unknown function with a conserved domain at its C-terminus. MIZ2 encodes a guanine-nucleotide exchange factor for ADP-ribosylation factor-type G proteins, which has been identified as GNOM. These findings suggest that roots possess molecular mechanisms essential for hydrotropism but independent of gravitropism. One of such mechanisms involves vesicle transport unique to hydrotropism in roots. Here we summarize recent progress on the molecular mechanism of root hydrotropism and the roles of MIZ1 and MIZ2.