Abstract:

In order to further explore the molecular regulation mechanism of PG during‘Fuping Jianshi’persimmon（Diospyros kaki L.）postharvest softening with different treatments, and to improve the persimmon ripening and softening process，the responses of DkPG1 gene and PG activities in persimmon fruit to propylene and 1-MCP at the room temperature were investigated by real-time quantitative PCR（RT-qPCR）approach and DNS method. The results showed that accompanying with fruit ripening，the expressions of DkPG1 gene in fruits with different treatments had the same trend on the transcript level that it first steadily increased to the maximum and then decreased. After 4 days of propylene treatment，the expression of DkPG1 gene increased to the maximum which was dramatically higher than the control，and it appeared 12 days ahead of the control；The expression peak of DkPG1 gene in fruits treated with 1-MCP appeared at 28 days，12 days later than the control，which was significantly lower than the control. The activity of PG in fruits treated with propylene rapidly increased, and the activity peak appeared at the same day DkPG1 gene expression peak appeared；1-MCP treatment made the activity peak of PG decrease and appear 4 days earlier than its DkPG1 expression peak. Besides，the results about the analyze of ethylene release rate and pectin component showed the expressions of DkPG1 gene were regulated by ethylene，and then affected the pectin component metabolism.

Key words: Diospyros kaki L., propylene, 1-MCP, polygalacturonase, real-time PCR