Effect of GA3 Treatment on Seed Development and Seed-Related Gene Expression in Grape

Abstract

BackgroundThe phytohormone gibberellic acid (GA3) is widely used in the table grape industry to induce seedlessness in seeded varieties. However, there is a paucity of information concerning the mechanisms by which GAs induce seedlessness in grapes.Methodology/Principal FindingsIn an effort to systematically analyze the cause of this GA3-induced seed abortion, we conducted an in depth characterization of two seeded grape cultivars (‘Kyoho’ and ‘Red Globe’), along with a seedless cultivar (‘Thompson Seedless’), following treatment with GA3. In a similar fashion to the seedless control, which exhibited GA3-induced abortion of the seeds 9 days after full bloom (DAF), both ‘Kyoho’ and ‘Red Globe’ seeded varieties exhibited complete abortion of the seeds 15 DAF when treated with GA3. Morphological analyses indicated that while fertilization appeared to occur normally following GA3 treatment, as well as in the untreated seedless control cultivar, seed growth eventually ceased. In addition, we found that GA3 application had an effect on redox homeostasis, which could potentially cause cell damage and subsequent seed abortion. Furthermore, we carried out an analysis of antioxidant enzyme activities, as well as transcript levels from various genes believed to be involved in seed development, and found several differences between GA3-treated and untreated controls.ConclusionTherefore, it seems that the mechanisms driving GA3-induced seedlessness are similar in both seeded and seedless cultivars, and that the observed abortion of seeds may result at least in part from a GA3-induced increase in cell damage caused by reactive oxygen species, a decrease in antioxidant enzymatic activities, and an alteration of the expression of genes related to seed development.

Gibberellin-induced changes in the transcriptome of grapevine (Vitis labrusca × V. vinifera) cv. Kyoho flowers

“…In grapevine, the effects of GA application on berry enlargement, the induction of seedlessness in seeded cultivars and ripening have been the subject of study for quite some time [17,19,37-39]. Interestingly, we have previously demonstrated that the exogenous pre-bloom application of GA 3 inhibited berry growth in seeded ‘Kyoho’ and ‘Red Globe’ cultivars, yet stimulated berry growth in ‘Thompson Seedless’ [17]. Similarly, it has also been shown that berry growth was inhibited in the seeded grape cultivar ‘Emperador’ and promoted in the seedless cultivar ‘Emperatriz’ upon GA 3 application [22].…”

“…The exogenous pre-bloom application of gibberellic acid (GA 3 ) to grapevine, which is an economically important crop that has long been an important component of the human diet, is commonly used to induce seedlessness [17,18], establish early ripening [19], and enhance berry size in seedless cultivars [20-22]. However, despite its importance in viticulture, the precise mechanism by which GA elicits these complex outcomes remains elusive.…”

Transcriptome analyses of seed development in grape hybrids reveals a possible mechanism influencing seed size

“…Previous studies [34, 58] have reported that seed weight of seedless grapes usually begin to decrease at 27 ~ 33 days after full bloom (DAF), and so seeds from 9 seedless and 9 seeded grape progeny were collected at 24, 27, 30, 33, 36, 39 and 42 DAF (Additional file 11: Figure S5). Fruits of all progeny individuals were slashed with scalpel, and then seeds were immediately picked out without damage using tweezers and put into centrifuge tubes which were already soaked in liquid nitrogen.…”

Effect of Streptomycin and GA3 Application on Seedlessness, Yield and Fruit Quality of 'Balady' Mandarin

“…The GA3 -induced increase in cell damage may be caused by reactive oxygen species, a decrease in antioxidant enzymatic activities, and an alteration of the expression of genes related to seed development (Cheng et al, 2013).…”

“…Gibberellic acid (GA3) is widely used to induce seedlessness in seeded varieties in grapes (Fukunaga & Kurooka, 1988, Ogasawara, 1985, Ogasawara and Hirata, 1985, Fellman et al, 1991, Shiba, 1980, Kazunori et al, 2001and Cheng et al, 2013, cherry (Beppu et al, 2001 and, loquat (Mesejo et al, 2010) and other fruits (Pharis and King, 1985).…”