We thank professor Yu-Zhong Zhang (State Key Laboratory of Microbial Technology, Shandong University, China) for support and assistance. Funding. This work was supported by the National Natural Science Foundation of China (31370104 and 31771899), the Natural Science Foundation of Hunan Province, China (2018JJ2497), and the Fundamental Research Funds for the Central Universities of Central South University (2018zzts392 and 2018gczd041).