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【目的】从山西省洪洞县的杨树丰产林中采集到几头自然染菌的杨尺蠖Apocheima cinerarius越冬蛹虫尸,经分离纯化得到一株病原真菌,定名为YHT01,确定该菌株的分类地位。【方法】用该菌株孢子悬浮液(1.0×108 conidia/m L)感染杨尺蠖蛹进行回接杀虫实验,扫描电镜观察菌株形态学特征,ITS序列测定并构建系统发育树对YHT01菌株进行分子鉴定。【结果】经YHT01菌株感染之后,杨尺蠖蛹节间处长出白色菌丝。该菌株在PDA培养基上的菌落呈椭圆形,白色,绒毛状,菌落背面呈橙黄色;扫描电镜观察结果显示,该菌株孢梗束呈扫帚状,分生孢子小,卵形至椭圆形,壁光滑,大小为(2.1-3.4)μm×(1.1-1.8)μm。该菌株的r DNA-ITS序列与Gen Bank中粉棒束孢Isaria farinosa(Holm:Fr.)Fr.(AB233337)的序列相似性达99%,在系统发育树的同一分支上。【结论】YHT01是杨尺蠖蛹的一株病原真菌,粉棒束孢Isaria farinosa。
【Objective】 The objective of this study was to collect overwintering pupal mites of Apocheima cinerarius, a naturally infected strain of Populus euphratica in Hongtong County, Shanxi Province. One pathogenic fungus was isolated and purified and named as YHT01. status. 【Method】 In this experiment, the pupae of Populus przewalskii were inoculated with 1.0 × 108 conidia / m L and the morphological characteristics of the strain were observed by scanning electron microscopy. The ITS sequence was determined and the phylogenetic tree was constructed. Identification. 【Result】 After the infection of YHT01 strain, the white mycelium grew in the internode of the pupal. The colonies of the strain on PDA medium were oval, white, and villous, and the back of the colonies was orange-yellow. The results of scanning electron microscopy showed that the sporulation of the strain was broom-like with small conidia, oval to oval, The walls are smooth and of size (2.1-3.4) μm × (1.1-1.8) μm. The sequence of rDNA-ITS of this strain was 99% identical to that of Isaria farinosa (Holm: Fr.) Fr. (AB233337) in GenBank, on the same branch of phylogenetic tree. 【Conclusion】 YHT01 is a pathogenic fungus of Isatis indigotica, Isaria farinosa.