The Function Research Of StSnRK1γ And StABI1 In Cold-induced Sweetening Of Potato Tubers

The improvement of potato processing quality is one of the problems that need to be solved in our country, and the key is to inhibit the accumulation of potato reducing sugar. Our previous research has proved that SbSnRK1 can bind to invertase inhibitor and invertase to form a complex to regulate the activity of invertase, in which the phosphorylation state of SbSnRK1 is very important. However, the function of other members of potato SbSnRK1 trimer and the phosphorylation mechanism have been rarely reported. In this research, we studied the beta gamma subunit of StSnRK1 as well as a phosphatase named StABI1. Results are as follows:1. We defined the beta gamma subunit of StSnRK1 in potato and analyzed its function in potato cold-induced sweetening. First, we cloned the homolog of Arabidopsis StSnRK1γ in potato. By yeast two hybrid asssay, we proved that StSnRK1γ can interact with SbSnRK1α, indicating that StSnRK1γ may act as a member of the heterologous trimer of SbSnRK1. Then we constructed its silencing vector and transformed potato. We detected the reducing sugar content and invertase activities in tubers of transgenic lines. Results showed that: compared with the control, the reducing sugar content of transgene lines decreased by 33.3%, 22.2%, 25.9%, respectively; the activities of invertase decreased by 30.7%, 56.0%, 63.3%, respectively. Moreover, the fried chips color of transgenic lines was improved to a certain extent. These results suggest that StSnRK1γ is involved in the regulation of potato cold-induced sweetening.2. We studied whether the phosphatase StABI1 play a role in potato cold-induced sweetening. First we cloned the StABI1 gene, and detected its expression in different resistance materials at different temperature treatments. Results show that after treat with low temperature, the expression of fold changes in the cold-induced sweetening sensitive materials are higher than in cold-induced sweetening resistance material. It indicates that StABI1 is more likely to be induced in the cold-induced sweetening sensitive materials under low temperature. We proved that StABI1 located in the cytoplasm. Finally, we constructed the silencing vector and transformed it in potato. We detected the reducing sugar content and invertase activities of transgene lines of StABI1. Results show that the reducing sugar content of transgene lines declined about 55%, and invertase activities decreased about 45%. And the chips color of transgene lines has been improved. In all our results indicated that StABI1 may regulate potato cold-induced sweetening by changing the activity of invertase.