野生柑橘炭疽病鉴定

Identification of Anthracnose on Wild Citrus

本研究对华中农业大学野生柑橘上的病害进行鉴定。运用形态学及ITS序列分析方法对病样进行系统鉴定。结果表明,从发病的野生柑橘枝稍病样上共分离到24个单孢菌株,这些菌株根据形态学及ITS序列分析方法分为3种真菌:(1)菌落粉红色,长势非常缓慢,孢子镰刀形,ITS序列分析鉴定为砖红镰孢菌Fusarium lateritium;(2)菌落灰黑色,气生菌丝多,孢子砖格状,ITS序列分析为链格孢菌Alternaria alternata;(3)菌落灰白色,气生菌丝较少,常产生橙色胶滴和黑色小粒点,分子孢子短杆状,ITS序列分析为胶孢炭疽菌Colletotrichum gloeosporioides。利用健康柑橘枝条对此3种真菌进行回接实验时,接种胶孢炭疽菌的枝条出现了跟采样枝条相同的症状,而且从发病的枝条上又分离到同样的炭疽菌;而接种链格孢及砖红镰孢的枝条不发病。该病害鉴定为胶孢炭疽菌C.gloeosporioides感染引起的炭疽病。

This study was carried out to identify the disease on wild citrus in the campus of Huazhong Agricultural University. The samples were collected and pathogens were identified based on the morphology and ITS sequence analysis. In total, 24 single spore isolates were ob- tained from the diseased shoot samples, and they showed three kinds of morphology and identified as different fungi by ITS analysis. （i）The colony appeared pink and grew slowly, produced falculate eonidia, ITS sequence analysis identified it as Fusariurn lateritium; （ii） The colo- ny appeared grey to black with much aerial mycelia, produced muriform conidia, ITS sequence analysis confirmed it as Alternaria alternata; （iii） The colony appeared grey, less aerial myeelia, often produced orange sticky droplets and small black spots, ITS analysis revealed it as Colletotrichum gloeosporioides. Pathogenicity was confirmed by inoculating these three kinds of fungi on healthy citrus stems, as a result, same symptoms as that of original diseased stem samples appeared by inoculating C. gloeosporioides but not F. luteritium and A. alternata, and C. gloeosporioides was re-isolated from the inoculated shoot. Therefore, morphology and ITS sequence analysis indicated that the stem disease was citrus anthracnose caused by C. gloeosporioides.