Study on the Difference of EXP and PsEXPA10 in Ripening Period of ‘jinmi’ plum and ‘qingcui’ plum

Abstract The softening of plum fruit is an important factor affecting its promotion in production. In order to explore the changes of extension (EXP)during the ripening and softening stage of plum fruit, ‘jinmi’ plum and ‘qingcui’ plum were used as experimental materials to study the difference of EXP activity and PsEXPA10 expression during plum maturation and softening period. The results showed that as the fruit matured, the hardness of the fruit decreased, but there was a difference in the magnitude and rate of decrease between the two varieties, and the decrease of ‘Jinmi’ plum was even greater. The expression trends of EXP and PsEXPA10 were basically the same. At 81 d after flowering, the expression of PsEXPA10 in peel and flesh of ‘jinmi’plum was the highest, and the activity of EXP reached the highest at 88 d after flowering. The expression levels of EXP and PsEXPA10 in peel and flesh of plum were gradually increased, and the highest values of PsEXPA10 expression in flesh of plum were all at 109 d after flowering, except that the expression level of PsEXPA10 in flesh of plum was at 102 d after flowering. The results showed that EXP was closely related to plum fruit ripening and softening. And this study also laid a foundation for further exploring the molecular mechanism of EXP’s role in plum fruit softening.