西瓜砧木种传镰刀菌的种类鉴定及其致病性研究

Study on Identification of Seedborne Fusarium species of Rootstock for Watermelon Grafting and Their Pathogenicity

本研究针对神力砧木种胚和福田将军砧木种壳分离得到的2个镰刀菌分离物,结合形态特征及分子生物学的方法进行了鉴定,并研究了其对西瓜砧木种子发芽的影响和幼苗的致病性。结果表明:2个分离物均为尖孢镰刀菌(Fusariumoxysporum)。2个尖孢镰刀菌分离物对西瓜砧木种子发芽有显著的影响,发芽势、发芽率、发芽指数、活力指数等指标均显著降低,且能导致西瓜砧木幼苗出现典型的枯萎症状,经柯赫氏法则检验证明其具有致病性。西瓜砧木种子传带尖孢镰刀菌并具有致病性为国内首次报道。

Two Fusarium isolates were obtained from seed embryo and seed coat of rootstock seeds （ cvs. Shenlizhenmu and Futianjiangjunzhenmu） for watermelon grafting ,repectively. The two isolates were identified using morphological methods and DNA sequencing analysis. Effects on seed germination and pathogenicity to seedlings of these two Fusarium isolates were also determined. The results showed that the two Fusarium strains were identified to be Fusarium oxysporum. They had significant effect on seed germination, compared to control treatment, which causing reduction of germination energy, percentage germination, germination index and vigor index significantly;they were pathogenic to rootstock seedlings and caused typical wilt symptom on leaves, fulfilled Koch＇ s postulates. To our knowledge, it＇ s the first report of seedborne F. oxysporum of rootstock for watermelon grafting can be pathogenic to rootstock seedlings in China.