1. State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, Guangdong 510640, China
2. Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, Guangdong 510640, China
3. College of Horticulture, South China Agricultural University, Guangzhou 510640, Guangdong, China
4. Donald Danforth Plant Science Center, St. Louis, Missouri 63132
5. Division of Plant Sciences, University of Missouri–Columbia, Columbia, Missouri 65211