Study On Metabolites Of Mutant Strain ?AOL_s00215g277 Of Arthrobotrys Oligospora And Their Functions

Secondary metabolites in fungi play important roles in maintaining the survival of fungi by influencing their developments to cope with changes in environmental conditions.Arthrobotrys oligospora is a nematode-trapping fungus which produces a type of arthrosporols as signal molecules.This type of compounds contains a hybrid carbon skeleton of a cyclohexanol moiety with a sesquiterpene chain.Ten genes were assumed to be involved in the biosynthese of arthrosporols.Here in this thesis,chemical study on the mutant with lack of the gene AOL_s00215g277 in the arthrosporols biosynthesis cluster was performed.Main results and innovations:1.Metabolic analysis of mutant ?AOL_s00215g277 and wild-type strain,revealed that the mutant strains have three huge unique peaks.Three compounds LX-1,LX-2,and LX-3 have been isolated from the cultural broth of mutant(35)AOL_s00215g277.Compound LX-1 was elucidated as a new compound with a novel carbon skeleton of toluquinol with a prenyl moiety instead of a farnesyl chain.Compounds LX-2 and LX-3 were known compounds which seemed to be not directly involved in the biosynthesis of arthrosporols,they were 4-hydroxyphenethyl-2?-(S)-hydroxypropanoate,4-hydroxyphenethyl-2?-(R)-hydroxypropanoate.Moreover,A new compound LX-4 and four known compounds were also isolated.They were 2-(4-hydroxyphenyl)ethanol,Tyrosol,ethyl 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)formate,2-hydroxy-3-(4-hydroxyphenyl)propionic acid methyl ester.2.Mutant strain ?AOL_s00215g277 display decreased spore germination rate compared to wild-type strain with 9.1%-11.8% lower than that of the wild-type strain,significantly increased trap formations and nematode-trapping ability with 1.7-1.6 fold higher than those of wild-type strain.In this study,metabolic profile of mutant ?AOL_s00215g277 was analyzed and chemical investigation on this mutant resulted in purification of 8 compounds including one new metabolite with novel carbon skeleton of a toluquinol with prenyl moiety.This result led to deduction that the gene AOL_s00215g277 was involved in the biosynthesis of the farnesyl moiety in the key precusor for arthrosporols.Based on previous research and bioinformatic analysis,the gene AOL_s00215g277 might be also involved in the biosynthesis of the rhamnosyl moiety of two new toluquinol glycosides from mutant AOL_s00215g276.