虫生真菌LL-01鉴定及对两种检疫性粉蚧的致病性
Identification of the entomopathogenic fungus LL-01 and assessing its pathogenicity to two mealybugs
黄 鹏；姚锦爱；蓝炎阳；余德亿；侯翔宇
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DOI：10.7679/j.issn.2095-1353.2022.063
作者单位：福建省作物有害生物监测与治理重点实验室，福建省农业科学院植物保护研究所， 福建省作物有害生物绿色防控工程研究中心，福州 350013；漳州农业科技园区研发中心，漳州 363204
中文关键词：蜡蚧轮枝菌；南洋臀纹粉蚧；石蒜绵粉蚧；致病性
英文关键词：Lecanicillium lecanii; Planococcus lilacinus; Phenacoccus solani; pathogenicity
中文摘要：
【目的】 为丰富南洋臀纹粉蚧Planococcus lilacinus和石蒜绵粉蚧Phenacoccus solani的生防菌资源。【方法】 本研究从感病南洋臀纹粉蚧上分离生防菌，采用基因序列分析方法进行种类鉴定，并在室内优化其培养条件，评估其对这2种检疫性粉蚧的致病性。【结果】 分离得到1株编号为LL-01的虫生真菌，经rDNA-ITS、18S rDNA和Nad1序列分析确定为蜡蚧轮枝菌；该菌的生长和产孢最适的温度为26 ℃，光周期为6L︰18D，碳源为果糖，氮源为干酪素，此条件下培养10 d的蜡蚧轮枝菌菌落直径和产孢量分别可达4.66 cm和3.16×108孢子/cm2；其侵染不同虫龄南洋臀纹粉蚧和石蒜绵粉蚧10 d后的LC50分别为9.80×104-9.17×105孢子/mL和5.00×104-5.30×105孢子/mL。浓度为1.00×108孢子/mL的蜡蚧轮枝菌侵染南洋臀纹粉蚧和石蒜绵粉蚧后第10天，其累计致死率分别为84.09%-97.62%和89.89%-98.85%，LT50分别为3.70-5.84 d和3.48-5.14 d；在侵染第5 天时，蛋白酶和几丁质酶活性分别达峰值19.44 U/mL和15.01 U/mL，脂肪酶活性在侵染第6天时达到峰值7.68 U/mL。【结论】 蜡蚧轮枝菌LL-01生长速度快、产孢量高，对这2种检疫性粉蚧的致病性强。
英文摘要：
[Objectives] To increase the number of fungal biocontrol agents available for controlling the mealybugs Planococcus lilacinus and Phenacoccus solani. [Methods] Fungi were isolated from fungus-infected mealybugs and their taxonomic statis, culture conditions and pathogenicity to P. lilacinus and P. solani were determined. [Results] A strain of the entomopathogenic fungus LL-01 isolated from infected P. lilacinus was identified as Lecanicillium lecanii on the basis of rDNA-ITS, 18S rDNA and Nad1 gene sequence analysis. The optimal culture conditions for the growth and sporulation of this strain were 26 ℃, 6L︰18D, with fructose as a carbon source and casein as a nitrogen source. Under these conditions, the colony diameter and sporulation of the LL-01 strain after ten days cultivation were 4.66 cm and 4.16×108 conidia/cm2, respectively. The LC50 values of this strain after 10 days for different instars of P. lilacinus and P. solani were 9.80×104- 9.17×105 conidia/mL and 5.00×104-5.30×105 conidia/mL, respectively. Mortality was 84.09%-97.62% and 89.89%-98.85%, respectively and the LT50 values for a dose of 1×108 conidia/mL were 3.70-5.84 d and 3.48-5.14 d, respectively. The peaks of protease and chitinase activity of the fungal strain were 19.44 U/mL and 15.01 U/mL, respectively, on the fifth day post-infection, and the peak lipase value was 7.68 U/mL recorded on the sixth day post-infection. [Conclusion] The fungul strain L. lecanii LL-01 has fast growth and high sporulation, and is strongly pathogenic to P. lilacinus and P. solani.