Amemiya Tsuyoshi, Kanayama Yoshinori, Yamaki Shohei, Yamada Kunio, Shiratake Katsuhiro
Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, 464-8601 Nagoya, Japan.
Planta. 2006 May;223(6):1272-80. doi: 10.1007/s00425-005-0176-x. Epub 2005 Dec 2.
The vacuole is a large, multifunctional organelle related to the processes of cell expansion, solute accumulation, regulation of cytoplasmic ion concentrations, pH homeostasis and osmoregulation, which are directly or indirectly achieved by vacuolar H+-pumps: vacuolar H+-ATPase (V-ATPase; EC 3.6.1.3) and vacuolar H+-pyrophosphatase (V-PPase; EC 3.6.1.1). In this study, we produced antisense-transgenic tomatoes (Lycopersicon esculentum L.) of the V-ATPase A subunit, which is under the control of the fruit-specific 2A11 promoter. One beta-glucuronidase (GUS)-transgenic line (GUS control) and seven A subunit antisense-transgenic lines were obtained. The amount of V-ATPase A subunit mRNA in fruit decreased in all antisense-transgenic lines, but in leaves showed no difference compared with the GUS control line and the nontransformant, suggesting that suppression of the V-ATPase A subunit by a 2A11 promoter is limited to fruit. The antisense-transgenic plants had smaller fruits compared with the GUS control line and the nontransformant. Surprisingly, fruits from the antisense-transgenic plants, except the fruit that still had relatively high expression of A subunit mRNA, had few seeds. Sucrose concentration in fruits from the antisense-transgenic plants increased, but glucose and fructose concentrations did not change. These results show the importance of V-ATPase, not only in fruit growth, but also in seed formation and in sugar composition of tomato fruit.
液泡是一种大型多功能细胞器，与细胞扩张、溶质积累、细胞质离子浓度调节、pH稳态和渗透调节等过程相关，这些过程直接或间接通过液泡H⁺泵实现：液泡H⁺-ATP酶（V-ATP酶；EC 3.6.1.3）和液泡H⁺-焦磷酸酶（V-PP酶；EC 3.6.1.1）。在本研究中，我们构建了受果实特异性2A11启动子控制的V-ATP酶A亚基的反义转基因番茄（番茄）。获得了一个β-葡萄糖醛酸酶（GUS）转基因株系（GUS对照）和七个A亚基反义转基因株系。所有反义转基因株系果实中V-ATP酶A亚基mRNA的量均减少，但与GUS对照株系和非转化株相比，叶片中无差异，这表明2A11启动子对V-ATP酶A亚基的抑制仅限于果实。与GUS对照株系和非转化株相比，反义转基因植株的果实较小。令人惊讶的是，除了A亚基mRNA仍有相对较高表达的果实外，反义转基因植株的果实种子很少。反义转基因植株果实中的蔗糖浓度增加，但葡萄糖和果糖浓度没有变化。这些结果表明V-ATP酶不仅在果实生长中，而且在番茄果实的种子形成和糖组成中都很重要。
