Expression of a constitutively activated plasma membrane H+-ATPase alters plant development and increases salt tolerance1[C][OA]
Expression of a constitutively activated plasma membrane H+-ATPase alters plant development and increases salt tolerance1[C][OA]
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DOI：
10.1104/pp.107.103762
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发表时间：
2007-08-01
期刊：
影响因子：
7.4
通讯作者：
Boutry, Marc
中科院分区：
文献类型：
--
作者：
Gevaudant, Frederic;Duby, Geoffrey;Boutry, Marc
质膜质子泵ATP酶（H+-ATP酶）在离子和营养物质运输的激活中起主要作用，并且已经被认为参与了几个生理过程，如细胞膨胀和耐盐性。其活性受C-末端自身抑制结构域调节，该结构域可通过磷酸化和调节14-3-3蛋白的结合而被置换，从而产生活化的酶。为了更好地理解这种激活的生理后果，我们分析了转基因烟草（烟草）植物表达野生型质膜H+-ATP酶4（wtPMA 4）或PMA 4突变体缺乏自抑制结构域（Δ PMA 4），产生组成型激活酶。wtPMA 4的表达比未转化的植物高4倍的植物没有表现出任何不寻常的表型，它们的叶和根的外部酸化率没有改变，而它们的体外H+-ATP酶活性显着增加。这表明，在体内，H+-ATP酶的过度表达是通过下调H+-ATP酶活性来补偿的。与此相反，植物表达PMA 4的特点是由一个较低的质外体和外部根pH值，异常的叶片倾斜，扭曲的茎，这表明在细胞扩张的变化。这通过体外叶片延伸和卷曲测定证实。因此，这些数据强烈支持H+-ATPase在植物发育中的直接作用。Delta PMA 4植物在萌发和幼苗生长期间也显示出增加的耐盐性，支持H+-ATP酶参与耐盐性的假设。
The plasma membrane proton pump ATPase (H+-ATPase) plays a major role in the activation of ion and nutrient transport and has been suggested to be involved in several physiological processes, such as cell expansion and salt tolerance. Its activity is regulated by a C-terminal autoinhibitory domain that can be displaced by phosphorylation and the binding of regulatory 14-3-3 proteins, resulting in an activated enzyme. To better understand the physiological consequence of this activation, we have analyzed transgenic tobacco (Nicotiana tabacum) plants expressing either wild-type plasma membrane H+-ATPase4 (wtPMA4) or a PMA4 mutant lacking the autoinhibitory domain (Delta PMA4), generating a constitutively activated enzyme. Plants showing 4-fold higher expression of wtPMA4 than untransformed plants did not display any unusual phenotype and their leaf and root external acidification rates were not modified, while their in vitro H+-ATPase activity was markedly increased. This indicates that, in vivo, H+-ATPase overexpression is compensated by down-regulation of H+-ATPase activity. In contrast, plants that expressed PMA4 were characterized by a lower apoplastic and external root pH, abnormal leaf inclination, and twisted stems, suggesting alterations in cell expansion. This was confirmed by in vitro leaf extension and curling assays. These data therefore strongly support a direct role of H+-ATPase in plant development. The Delta PMA4 plants also displayed increased salt tolerance during germination and seedling growth, supporting the hypothesis that H+-ATPase is involved in salt tolerance.