1. College of Horticulture, Sichuan Agricultural University, No 211 Huimin Road, Wenjiang District, Chengdu 611130, Sichuan, China
2. National R & D Centre for Citrus Preservation, Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China