Jiangsu Academy of Forestry, Dongshanqiao, Jiangning, Nanjing, Jiangsu, China.
PLoS One. 2012;7(10):e48183. doi: 10.1371/journal.pone.0048183. Epub 2012 Oct 25.
Vacuolar H(+)-ATPase (V-H(+)-ATPase) may play a pivotal role in maintenance of ion homeostasis inside plant cells. In the present study, the expression of V-H(+)-ATPase genes was analyzed in the roots and leaves of a woody plant, Broussonetia papyrifera, which was stressed with 50, 100 and 150 mM NaCl. Moreover, the expression and distribution of the subunit E protein were investigated by Western blot and immunocytochemistry. These showed that treatment of B. papyrifera with NaCl distinctly changed the hydrolytic activity of V-H(+)-ATPase in the roots and leaves. Salinity induced a dramatic increase in V-H(+)-ATPase hydrolytic activity in the roots. However, only slight changes in V-H(+)-ATPase hydrolytic activity were observed in the leaves. In contrast, increased H(+) pumping activity of V-H(+)-ATPase was observed in both the roots and leaves. In addition, NaCl treatment led to an increase in H(+)-pyrophosphatase (V-H(+)-PPase) activity in the roots. Moreover, NaCl treatment triggered the enhancement of mRNA levels for subunits A, E and c of V-H(+)-ATPase in the roots, whereas only subunit c mRNA was observed to increase in the leaves. By Western blot and immunocytological analysis, subunit E was shown to be augmented in response to salinity stress in the roots. These findings provide evidence that under salt stress, increased V-H(+)-ATPase activity in the roots was positively correlated with higher transcript and protein levels of V-H(+)-ATPase subunit E. Altogether, our results suggest an essential role for V-H(+)-ATPase subunit E in the response of plants to salinity stress.
液泡 H(+)-ATP 酶（V-H(+)-ATP 酶）可能在维持植物细胞内离子稳态中发挥关键作用。在本研究中，分析了木质植物构树的根和叶中 V-H(+)-ATP 酶基因的表达，该植物受到 50、100 和 150 mM NaCl 的胁迫。此外，通过 Western blot 和免疫细胞化学研究了亚基 E 蛋白的表达和分布。结果表明，NaCl 处理明显改变了构树根和叶中 V-H(+)-ATP 酶的水解活性。盐胁迫显著增加了根中 V-H(+)-ATP 酶的水解活性。然而，叶中 V-H(+)-ATP 酶水解活性只有轻微变化。相反，在根和叶中都观察到 V-H(+)-ATP 酶的 H+泵活性增加。此外，NaCl 处理导致根中 H+焦磷酸酶（V-H(+)-PPase）活性增加。此外，NaCl 处理触发根中 V-H(+)-ATP 酶亚基 A、E 和 c 的 mRNA 水平增加，而仅观察到叶中亚基 c 的 mRNA 增加。通过 Western blot 和免疫细胞化学分析，亚基 E 被证明在根中对盐胁迫有反应而增加。这些发现表明，在盐胁迫下，根中 V-H(+)-ATP 酶活性的增加与 V-H(+)-ATP 酶亚基 E 的转录和蛋白水平的升高呈正相关。总之，我们的结果表明 V-H(+)-ATP 酶亚基 E 在植物对盐胁迫的反应中起重要作用。
