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为查明广东和广西地区家蚕Bombyx mori病原白僵菌的来源及其菌株间的相互关系,本研究利用了微卫星标记(simple sequence repeats,SSRs)技术,分别对采自广东、广西蚕区的白僵菌菌株居群之间和居群之内的遗传多态性进行了研究。结果发现,两广白僵菌居群之间的基因分化系数(Gst)是0.0590,多态位点百分率(PPL)为97.73%,Nei氏基因多样性指数(H)为0.1896,Shannon氏信息多样性指数(I)为0.3165,表明两广家蚕来源的白僵菌居群间的遗传分化较小;两个居群内部的遗传多态性研究结果分别是广东白僵菌居群的PPL=68.18%,H=0.1910,I=0.3044,而广西白僵菌居群的PPL=65.91%,H=0.1713,I=0.1791,表明广东白僵菌居群的遗传多样性水平较高,广西白僵菌居群遗传多样性水平相对较低。最后,利用Nei氏遗传距离进行了两广地区白僵菌菌株间地理来源关系的聚类分析,结果表明实验室保存菌株单独聚为类群Ⅰ,而不同采集地的菌株聚为类群Ⅱ。结果反映了生产来源的白僵菌菌株存在遗传多态性和基因分化现象,暗示了家蚕白僵病病原来源的复杂性,还说明应用SSRs技术进行家蚕白僵病病原的溯源是一条可行的途径。
In order to find out the origin of Beauveria bassiana in Bombyx mori and the correlation between the isolates in Guangdong and Guangxi, simple sequence repeats (SSRs) were used in this study. Beauveria bassiana strains were studied among populations and within populations. The results showed that Gst was 0.0590, PPL was 97.73%, Nei’s gene diversity index (H) was 0.1896, Shannon’s information diversity The index (I) was 0.3165, indicating that the genetic differentiation of Beauveria bassiana strains from Guangdong and Guangxi was small. The results of genetic polymorphism of the two populations were PPL = 68.18% H = 0.1910, I = 0.3044, while PPL of Beauveria bassiana in Guangxi was 65.91%, H = 0.1713, I = 0.1791, indicating that the genetic diversity of Beauveria bassiana was high, The level of genetic diversity is relatively low. Finally, using Nei ’s genetic distance to cluster the geographical origin relationship of Beauveria bassiana strains in Guangdong and Guangxi, the results showed that the laboratory preserved strains were grouped into group Ⅰ only, while the strains from different collection sites were clustered into group Ⅱ. The results reflect the existence of genetic polymorphism and gene differentiation of Beauveria bassiana strains of origin, suggesting the complexity of origin of the pathogen of B. bassiana in silkworm. It also shows that it is a feasible way to trace the pathogen of B. bristemi by using SSRs technology .