Isolation Of Lipopeptide Compounds And Their Inhibition Of Pathogens Of Flax Blight

Flax belongs to the genus Flax,and it is an important economic crop in the cold and high drought areas of Shanxi,Hebei,Inner Mongolia,Ningxia and Gansu.Fusarium oxysporum f.sp.lini is a pathogen of flax blight,which is one of the important reasons for reducing the yield of flax.Therefore,the development of biocontrol agents against F oxysporum,a pathogen of flax blight,is biological.meaningful.A strain of Bacillus atrophicus SF1 was isolated in the early stage of the laboratory.The bacteriostasis test showed that the antibacterial rate against F oxysporum can be as high as 60%.The whole gene sequence of SF1 is found to contain related genes encoding volatile bacteriostatic substances and non-volatile antibacterial substances.Among the non-volatile antibacterial substances,lipopeptide is one of the main active substances inhibiting fungal growth,but currently There are few studies on the inhibitory effect and mechanism of lipopeptide on F oxysporum.In this study,the single factor experiment combined with the response surface experiment was used to optimize the fermentation medium of the high-yield lipopeptide of strain SF1,and the lipopeptide produced by the fermentation of the strain was extracted and purified.The lipopeptide was used to treat the pathogen of flax blight and the lipopeptide was explored.Pathogen mycelial growth,morphology and cell membrane effects.The main findings are as follows:(1)The fermentation medium and culture conditions of strain SF1 were tested by single factor experiment and response surface optimization,and the production of lipopeptide was increased by 24.57%.(2)The lipopeptides of the fermentation broth of SF1 were extracted by acid precipitation,and three peaks were obtained by reversed-phase preparative liquid chromatography.The mass spectrometry showed that Irisin had a mass-to-mass ratio(m/z)was 1056.5,1070.5,1084.5 and a small amount of 1042.5.(3)The lipopeptide can cause abnormal morphology of the hyphae of the F oxysporum f.sp.lini strain,the cell membrane is damaged,the top of the hyphae expands,and the annular tip of the diaphragm appears.