The Role Of Ethylene On Berry Abscission Of Vitis Vinifera And Analysis Of Vvacs1 And VvACO Gene Expression

Due to a short storage period,grapes are seriously affected in product quality,storage time and shelf life by berry decay,dry rachis,browing,berry drop and so on.The previous results showed that the grape rachis was respiratory climacteric and the fruits were non respiratory climacteric,and the ethylene production rate of rachis was 10 times higher than that of the fruits.ACS and ACO are two key genes in ethylene synthesis.Our previous results showed that Vv ACS1 gene was specifically expressed in grape rachis,and Vv ACO was the key gene in fruit development.In this study,the purpose is to explore the relationship between ethylene and grape fruit abscission by comparing the correlation between pulling force and ethylene production rate in the rachis of different grape varieties.In order to lay the foundation to regulate ethylene synthesis of grape rachis,the expression of Vv ACS1 and Vv ACO gene is analyzed by selecting representative grape varieties to study the correlation between the expression of Vv ACS1 and Vv ACO genes and ethylene production rate.The main results are as follows:1.The correlation between pulling force and ethylene production rate of grape rachis in 50 grape varieties was analyzed when ripening,and the result showed that the correlation was not significant and the correlation coefficient is-0.110.2.The correlation between pulling force and ethylene production rate of the rachis of 15 grape varieties was studied during the postharvest storage for 6 days,and the result showed that pulling force in rachis of V.vinifera ‘Reliance' ‘Zui jin xiang' ‘Red bala' was significantly negative correlation with ethylene production in high ethylene production varieties,and the correlation coefficient was-0.602*,-0.824*,-0.630*,respectively.In some varieties with low ethylene production in rachis,the correlation coefficient between the ethylene production rate and pulling force was smaller.3.The correlation between pulling force and berry hardness was analyzed in 50 different grape varieties,and the result showed that pulling force was significantly correlated with berry hardness,and the correlation coefficient was 0.502**.4.The expression of Vv ACS1 and Vv ACO genes and the ethylene production rate inthe rachis of high ethylene production varieties and low ethylene production varieties were analyzed,respectively.In three of the tested four varieties with high ethylene production in rachis,the expression of Vv ACS1 and Vv ACO was positively correlated with ethylene production.In the rachis of‘Reliance'grape,the expression of Vv ACS1 gene was positively correlated with the ethylene production rate,and the correlation coefficient was 0.885*.In the rachis of‘Black Beet'grape,the expression of Vv ACS1 and Vv ACO genes was positively correlated with the ethylene production rate,and the correlation coefficient was 0.762 and 0.730,respectively.In the 'Rizamat' grape rachis,the correlation coefficient between the expression of Vv ACO2 and Vv ACO3 genes and ethylene production rate was 0.952** and 0.691,respectively.