Abstract:

GA3ox genes can transform several inactive gibberellin to the physiological active in plant gibberellin anabolism. VvGA3ox gene families were cloned from seed（cv. Pinot Noir）and seedless（cv. Thompson Seedless）grape varieties. We performed gene structure analysis，chromosome mapping analysis and phylogenetic analysis，and also investigated expression patterns of VvGA3ox genes in various grape organs and at different stages of ovule development. In this study，3 GA3ox genes（VvGA3ox1–VvGA3ox3）were identified in the grape genome. These 3 genes all contain two extrons and one intron  whose cDNA sequence length was 1 313，1 225 and 1 480 bp，respectively. Expression analysis of the grape VvGA3ox genes in various organs demonstrated that VvGA3ox1 exhibited a low level in ovule tissue which expressed a high level in root tissue，while VvGA3ox2 and VvGA3ox3 exhibited a higher level in flower and ovule tissues. The expression patterns of VvGA3ox genes were distinct during ovule development，VvGA3ox1 showed expression that up-regulated at the 30 DAF（day after full-bloom）and then down-regulated in cv. Pinot Noir and cv. Thompson Seedless grape. Expression of VvGA3ox2 in cv. Pinot Noir significantly up-regulated at the 20–30 DAF and down-regulated later，while the ovule expression in cv. Thompson Seedless was slowly down-regulated and then up-regulated. Expression of VvGA3ox2 in cv. Pinot Noir was gradually down-regulated. However，the expression in cv. Thompson Seedless was up-regulated at the 10–15 DAF and then down-regulated to the level that in cv. Pinot Noir. This research shows that VvGA3ox genes exist significant differences between seedless and seed varieties，which may be related to grape seedlessness.

Key words: Vitis vinifera, gibberellin, VvGA3ox, gene cloning, expression analysis