Laboratory of Fruit Genetics Engineering, The Institute of Enology and Viticulture, University of Yamanashi, Kofu, Yamanashi 400-0005, Japan.
Mol Biol Rep. 2012 Jul;39(7):7823-9. doi: 10.1007/s11033-012-1625-9. Epub 2012 Apr 26.
We report the characterization of VvIAA9, an auxin/indole-3-acetic acid (Aux/IAA) protein, in grapevine (Vitis vinifera L.). VvIAA9 was expressed abundantly in leaves and berries. VvIAA9 transcription was drastically upregulated from anthesis to onset of ripening (termed véraison), in which berry diameter rapidly increased. Treatment with exogenous IAA induced VvIAA9 expression in grape leaves, suggesting that VvIAA9 is an auxin-responsive Aux/IAA protein. The overexpression of VvIAA9 in Arabidopsis thaliana promoted plant growth, including rapid floral transition. However, no morphological differences were observed between the control plant and the VvIAA9-overexpressing plant. The overexpression of VvIAA9 in Arabidopsis plants rendered the plants hyposensitive to exogenous IAA. The exogenous IAA treatment did not induce VvIAA9-overexpressing Arabidopsis plant growth and expression of IAA-responsive HAT2. Taken together, we conclude that grape Aux/IAA9 protein is likely to play a crucial role as a plant growth regulator.
我们报告了葡萄（Vitis vinifera L.）中生长素/吲哚-3-乙酸（Aux/IAA）蛋白 VvIAA9 的特征。VvIAA9 在叶片和浆果中大量表达。VvIAA9 的转录从开花到成熟开始（称为 véraison）急剧上调，在此期间浆果直径迅速增加。用外源 IAA 处理诱导葡萄叶片中 VvIAA9 的表达，表明 VvIAA9 是一种生长素响应的 Aux/IAA 蛋白。在拟南芥中过表达 VvIAA9 促进了植物的生长，包括快速的花转变。然而，在对照植物和 VvIAA9 过表达植物之间没有观察到形态差异。在拟南芥植物中过表达 VvIAA9 使植物对外源 IAA 的反应性降低。外源 IAA 处理不会诱导 VvIAA9 过表达的拟南芥植物生长和生长素响应的 HAT2 的表达。综上所述，我们得出结论，葡萄 Aux/IAA9 蛋白可能作为植物生长调节剂发挥重要作用。
