This research was jointly supported by National Natural Science Foundation of China (31372319, 31572416, 31402084), the Hubei Provincial Key Project for Scientific and Technical Innovation (2014ABA022), Hubei Provincial Research and Development Program (2010BB023), Hubei Provincial Technology and Innovation Program (2016ABA121), Natural Science Foundation of Hubei Province (2016CFA070), Research and Innovation Initiatives of WHPU (2016J08), the Hubei Hundred Talent Program, Agriculture and Food Research Initiative Competitive Grants (2014-67015-21770) of the USDA National Institute of Food and Agriculture, and Texas AgriLife Research (H-82000). The authors declare that they have no conflict of interest.