ACKNOWLEDGMENTS
We thank Dr. Jingquan Yu (Zhejiang University, Hangzhou, China) for providing excellent technical help with the measurement of endogenous phytohormones. The research was funded by the National Key Research and Development Program of China (2017YFE0114500), the National Natural Science Foundation of China (31772316 and 31471878), and Natural Science Foundation of Zhejiang Province, China (LZ17C150002).