莴笋炭疽病病原鉴定

Anthracnose of lettuce caused by Marssonina panattoniana in Gansu province

摘要:

【背景】2018年7?8月，甘肃省兰州市永登县武胜驿镇种植的莴笋大面积发生炭疽病，约40%的地块发病，绝收面积达10%。【目的】明确莴笋炭疽病的病原。【方法】采用组织分离法进行病原菌分离；通过Koch’s法则明确分出病菌的致病性；采用形态学和分子生物学方法对病原菌进行种类鉴定。【结果】分离得到形态特征一致的真菌菌株3株。在PDA平板上20 °C培养7 d，病菌分生孢子无色，单隔，梭形，(10.44?19.40) μm×(2.61?4.48) μm。代表性菌株Lett-11 接种莴笋离体叶片可引起与自然发病相似的症状。BLASTn分析结果显示，菌株Lett-11 (GenBank登录号MK252097)的rDNA-ITS序列与莴苣盘二孢菌Marssonina panattoniana strain CBS 163.25 (GenBank登录号MH854831.1)的序列相似性达99%。【结论】引起莴笋炭疽病的病原菌被鉴定为莴苣盘二孢菌Mar. panattoniana [Synonymy: Microdochium panattonianum]，这是莴苣盘二孢菌引起莴笋炭疽病在甘肃的首次报道。

Abstract:

[Background] In July to August 2018, anthracnose of lettuce occurred in a large area of Wushengyi town, Yongdeng county, Lanzhou city, Gansu province, China. About 40% fields suffered from the disease, and 10% fields failed to harvest. [Objective] Identify the pathogen of anthracnose on lettuce. [Methods] Pathogen isolation was carried out by means of diseased tissue isolation method. Koch’s rule was used to prove the pathogenicity of fungal strain isolated from lettuce. Morphological and molecular biological methods were used to identify the pathogen. [Results] Three fungal strains with similar morphological characteristics, were isolated from diseased samples. Conidia fusiform, with one septum, slightly curved, (10.44?19.40) μm×(2.61?4.48) μm, when the pathogen was cultured on PDA medium for 7 d at 20 °C. Artificial inoculation with representative strain Lett-11 on detached lettuce leaves, induced symptoms similar to in field. BLASTn analysis showed that the ITS sequences of strain Lett-11 (GenBank accession No. MK252097) had a 99% homology with Marssonina panattoniana strain CBS 163.25 (GenBank accession No. MH854831.1). [Conclusion] Pathogen causing anthracnose on lettuce was identified as Marssonina panattoniana [Synonymy: Microdochium panattonianum]. This is the first report of anthracnose of lettuce caused by Mar. panattoniana in Gansu province, China.