玫烟色棒束孢的遗传地理差异及对B型烟粉虱的致病性

Genetic geographical difference of Isaria fumosorosea and its pathogenicity against B-biotype Bemisia tabaci

【目的】研究不同地区玫烟色棒束孢Isaria fumosorosea的遗传地理差异,探讨其对B型烟粉虱Bemisia tabaci的致病性。【方法】从广东、福建和青海地区土壤分离得到16株玫烟色棒束孢菌株用生物信息学的方法分析供试菌株ITS序列的相似性,并构建系统发育树;采用浸渍法测定供试菌株分生孢子对B型烟粉虱2龄若虫的生物活性。【结果】供试菌株与参考菌株(KX057373.1、KX057375.1)ITS序列的相似性高于97.7%;9株广东菌株与6株福建菌株的ITS序列没有地理差异;青海菌株If TS01与参考菌株KX057375.1的ITS序列几乎相同,且与福建菌株If FJ02、If FJ06及广东菌株If GD17的ITS序列高度相似。16株菌株均以孢子剂量10~7 mL^(-1)处理B型烟粉虱2龄若虫,处理后第10天若虫的病死率为47%~86%;其中,菌株If FJ06、If GD02和If TS01处理后的B型烟粉虱2龄若虫病死率达80%以上。【结论】不同地区的玫烟色棒束孢菌株ITS序列没有明显的地理差异,其对烟粉虱的致病力与ITS序列及地理分布没有关系。研究发现3株对烟粉虱致病力较高的菌株,具有进一步研究价值。

【Objective】To study the genetic geographical difference of Isaria fumosorosea strains isolated from different regions, and the pathogenicity of I. fumosorosea to B-biotype Bemisia tabaci.【Method】Sixteen strains of I. fumosorosea were isolated from soils of Guangdong, Fujian, and Qinghai. The bioinformatics analysis was used to identify ITS sequences similarities of the 16 strains, and the pathogenetic tree was constructed. The immersion method was employed to evaluate the pathogenicities of I. fumosorosea strains against second-instar nymphs of B-biotype B. tabaci.【Result】The ITS sequences similarities between the test I. fumosorosea strains and the reference strains（KX057373.1, KX057375.1） were over 97.7%. Nine strains from Guangdong and six strains from Fujian had no geographic difference. The ITS sequence of Qinghai strain IfTS01 was almost the same as that of reference strain（KX057375.1）, and highly similar to the strain IfFJ02、IfFJ06 of Fujian and strain IfGD17 of Guangdong. The fatality rate of B-biotype B. tabaci ranged from 47% to86% after 10 days treatment with 10 mL （-1） conidia of the 16 I. fumosorosea strains. The most effective strains,IfFJ06, IfGD02 and IfTS01, caused above 80% fatality rate of B. tabaci.【Conclusion】There is no obviousdifference of genetic geography among ITS sequences of I. fumosorosea strains isolated from different areas.The pathogenicity of I. fumosorosea strains aganist B. tabaci is not related to its geographical distribution and ITS sequence similarity. There are three strains with high pathogenicity to B. tabaci,which can be used for further research.