Study On The Physiological And Molecular Mechanism Of Gibberellin-induced Seedless Of ’Zuijinxiang’ Grape

Gibberellin plays an important role in the normal growth and development of grapes.Gibberellin can not only promote the fruit enlargement of seedless varieties,but also act on some seedless varieties to produce seedless fruits.At present,researchers have done a lot of research on the effect of gibberellin on fruit enlargement,but there are few studies on the mechanism of gibberellin inducing seedless grape fruits.To this end,this study through the application of exogenous gibberellin,to explore the ’drunk incense’ fruit seed growth and development of the impact,using different experimental methods and instruments for the determination of hormones,polyamines and other active substances;Bidirectional electrophoresis and transcriptome techniques were used for molecular analysis.The research results are as follows:1.In order to understand the role of exogenous gibberellin in inducing seedless,the’Zuijinxiang’ grape was used as the experimental material.The grape inflorescence was treated at one day before flowering,and the changes of endogenous hormones and polyamines in different time were determined.The results showed that the exogenous gibberellin treatment could lead to the changes of gibberellin,auxin and abscisoid content in grape fruits,and the(IAA+GA3)/ABA ratio in the treatment group was decreased.Exogenous gibberellin can change the content of polyamines and increase the Put content,while the content of Spd and Spm decreases.The value of(Spd+Spm)/Put in the treatment group is significantly higher than that in the control group.Exogenous gibberellin treatment can not only cause the change of fruit IAA and ABA content,but also affect the change of polyamine content,indicating that there is a certain relationship between different hormones and hormones and polyamine.Changes in the value of(IAA+GA3)/ABA and(Spd+Spm)/Put may lead to embryo dysplasia,indicating that embryo abortion is the result of the combined action of a variety of life regulating substances.2.We used ’Zuijinxiang’ pollen and ovules as the experimental material,a series of physiological and biochemical experiments were conducted.The results showed that gibberellin treatment reduced the pollen viability,increase H2O2 content in the pollen and triggered the accumulation of reactive oxygen in embryo sac.These results show that exogenous gibberellin can affect pollen viability and embryo sac development by affecting the redox balance.3.Exogenous gibberellin can cause changes in gene expression of multiple metabolic pathways,which are mainly related to hormone balance,signal transduction,embryo development,flower organ development,pollination and cell apoptosis.The expression of ABA synthesis genes were up-regulated by gibberellin and the ABA content was increased.In polyamine synthesis pathway,gibberellin induced the down-regulation expression of methionine dehydrogenase and arginine synthase,resulting in the decrease of Spd and Spm contents.In addition,exogenous gibberellin also caused up-regulated expression of antioxidant enzyme genes.Gibberellin also inhibited the metabolism of lignin in the upstream of lignin synthesis.All these aspects indicated that exogenous gibberellin treatment had adverse effects on the normal growth and development of seeds.We initially obtained key candidate genes related to ovule development and regulation,which mainly focused on hormone balance regulation,cell apoptosis,seed coat and endosperm development and ovule development..4.In this study,inflorescences of ’Zuijinxiang’(V.vinifera L.)were treated with 50 ppm GA3 during flowering,and berries were sampled at days 5,12,19,and 26 after flowering for proteomic analysis.A total of 45 spots showed an over twofold difference in volume between the treatments and controls,among which 38 proteins were successfully identified and assigned to eight functional groups,chief among groups are metabolic and biosynthetic process,stress response,oxidoreductase activity.In addition to their roles in plant development,this study also indicated GAs had an effect on reactive oxygen and antioxidant activities within grape tissues.GAs could cause cell damage and subsequent seed abortion,decrease in antioxidant enzymatic activities,and alterations in the expression of genes related to seed development.