代谢组学方法鉴定球孢白僵菌孢子萌发和杀虫毒力相关的标记物

Identification of spore germination and virulence related biomarkers from Beauveria bassiana using an LC-MS-based metabolomic technique

【目的】识别球孢白僵菌萌发和杀虫毒力相关的标记物。【方法】本研究对7个球孢白僵菌菌株的孢子进行萌发率和对茶毛虫毒力进行测定,采用基于LC-MS的代谢组学方法,识别菌丝和孢子提取物中与萌发和毒力有关的标记物。【结果】高毒力菌株的菌丝中具有高含量的carnitine、hercynine、acetylcarnitine、α,α-trehalose;Octa-Me、arg-arg-gln、phosphatidylethanolamine[PE(18∶2/0∶0)]、phosphotidylcholine[PC(18∶3/0∶0)]和PC(18∶2/0∶0)。高萌发率菌株的孢子中具有高含量的2,3-dimethylmaleate、acetylcarnitine、propionyl-carnitine和PC(18∶2/0∶0)。高毒力菌株的孢子中具有高含量的histamine、2,5-pyrrolidinedicarboxylic acid;Diamide、carnitine、acetylcarnitine、propionyl-carnitine、butyrylcarnitine、PE(18∶2/0∶0)、PC(16∶1/0∶0)和PC(18∶3/0∶0)。此外,对菌丝中杀虫相关的环肽beauverolides,beauvericins和bassianolide进行相对含量比较分析,发现单独一种肽的含量高低与菌株对茶毛虫的毒力没有直接关系,但高毒力的Bb1898菌株中的9种肽同时具有较高的含量暗示它们可能发挥协同作用。【结论】毒力和萌发的共同标记物是脂酰肉碱和磷脂,它们可能具有维持附着胞膨压和为穿透寄主提供能量的功能。其它标记物,如在高毒力菌丝中发现的hercynine和α,α-trehalose;高萌发率孢子中的2,3-dimethylmaleate,高毒力孢子中的histamine和2,5-pyrrolidinedicarboxylic acid Diamide,它们的作用原理有待进一步研究。

[Objective] To identify biomarkers associated with germination and virulence of Beauveria bassiana.[Methods]Spore germination rate and virulence of seven B. bassiana isolates against Euproctis pseudoconspersa were determined,and an LC-MS-based metabolomic analysis was applied to identify the biomarkers from mycelia and conidial extracts associated with spore germination and virulence.[Results] The metabolites of carnitine,hercynine,acetylcarnitine,α,α-trehalose; Octa-Me,arg-arg-gln,phosphatidylethanolamine（PE（18：2/0：0））,phosphotidylcholine （PC（18：3/0：0）） and PC（18：2/0：0）） were higher in the mycelia of highly virulent isolates than those less virulent strains.Conidia of isolates with a high germination rate were characterized by containing higher levels of 2,3-dimethylmaleate,acetylcarnitine,propionyl-carnitine and PC（18：2/0：0）.Histamine,2,5-pyrrolidinedicarboxylic acid;Diamide,carnitine,acetylcarnitine,propionyl-carnitine,butyrylcarnitine,PE（18：2/0：0）,PC（16：1/0：0） and PC（18：3/0：0） were higher in the conidia of highly virulent isolates.Furthermore,relative content comparison of insecticidal cyclopeptides,such as beauverolides,beauvericins and bassianolide in mycelia showed that the content of a single peptide was not highly related to fungal virulence. However,the contents of 9 peptides were found higher in the highly virulent isolate Bb1898,suggesting that they might exert synergetic effects against insect hosts. [Conclusion] The common biomarkers related to fungal virulence and germination are acyl carnitine and phospholipid which may play roles in maintaining appressorium turgor pressure and providing energy for penetrating the host cuticle.