太子参叶斑病病原菌的分离与初步鉴定

Isolation and preliminary identification of pathogens causing leaf spot on Pseudostellaria heterophylla

为明确太子参叶斑病病原菌种类以便更好地防治病害,以太子参叶斑病病叶作为研究材料,从中分离、纯化、形态学观察和分子鉴定病原菌.结果显示:分离所得的5株病原菌菌落形态存在差异,经致病性测定A菌为致病菌,A菌株在不同培养基上生长,形态略有差异;显微镜下观察分生孢子器呈黑色有孔口大小不等,菌丝有分枝,具隔膜,淡褐色,分生孢子椭圆形,有2个油球,表面光滑.提取A菌株基因组DNA,进行内源转录间隔区聚合酶链式反应扩增(internally transcribed spacer-polymerase chain reaction,ITS-PCR),序列分析结果与GeneBank中Ascomycota sp.的一致性达97%,结合形态特征与ITS分子序列将致病菌A菌株鉴定为壳二孢属(Ascomycota sp.).

In order to clarify the pathogen types of Pseudostellaria heterophylla leaf spot and provide refer-ence for the comprehensive control of the disease.The isolates from diseased leaves were identified based on morphological characteristics and molecular biology.The results showed that there were differences in colony morphology of 5 isolates associated with P.heterophylla leaf spot.Tie-back measurement of pathogenicity showed that A strain was the main pathogen.Strain A exhibited different morphological characteristics on the different medium.The conidia had different sizes of black holes through microscope observation.Mycelium branched,septate,pale brown.Conidia elliptic,having 2 oil balls,smooth surface.The DNA of strain A was ex-tracted and amplified by internally transcribed spacer-polymerase chain reaction(ITS-PCR).The ITS se-quence was 97%consistent with Ascomycota sp.in GeneBank.The strain A was identified as Ascomycota sp.based on morphological characteristics and molecular ITS sequence.