Investigation Ontheagricultural Activity Of Twoplantendophytes Secondary Metabolites

As a kind of natural resource library,plant endophytes resources are widely used in the environment.The fermentation products of natural products may provide a variety of novel and unique chemical structure for us to creat new agricultural antibiotics.In this study,based on the biologically active endophytes,nature products which are used to separate,identify and evaluate from their secondary metabolites.The main results are as follows: 1、Seven compounds are isolated from the fermentation ofCylindrocarpon olidum W1,and theyare identified asascochlorinanalogues by nuclear magnetic resonance(NMR),infrared spectroscopy(IR),ultraviolet and UV-visible spectrumand(UV)and high resolution mass spectrometry(HRMS).The ascochlorin analogues have some inhibitory effects on the pathogenic fungi and bacteria.In general,the compounds had a strong inhibitory effect on Gram-negative bacteria and showed weak activity against Gram-positive bacteria.The inhibitory activity of four compounds against Ralstonia solanacearum was obviously,and the inhibitory activity of W1-4 on Sclerotinia sclerotioruis 13.65μg / ml.In contrast to the agronomic activity of ascochlorinanalogues,the antifungal activity of the ascochlorin varies with the change in its structure,and the 3-position substituents of the benzene ring structure has a greater influence on the antifungal activity than the 5-position substituent on the benzene ring structure.The change of the second carbon-carbon unsaturated double bond structure or the structure of the cyclohexane on the compound activity of the 3-membered hydrocarbon chain on the benzene ring structure has a greater influence on the antifungal activity and the change in the substituents at the 5-position of the benzene ring structure has little effect on the activity of the compound.2、An endogenous actinomycete(named CSF09)with antibacterial and insecticidal activity was isolated from the roots of Eleusine indica(L.)Gaertn by tissue homogenization.It is identified as Streptomyces lateritius by 16 S rDNA sequence.One active compound was isolated from its secondary metabolites by activity tracking,and is identified as 4-methoxy salicylaldehyde.The antibacterial and insecticidal activity of 4-methoxy salicylaldehyde are evaluated.The insecticidal contact activity on armyworm is not strong.However,the virulence of housefly is superior to rotenone,and has the advantage of quick action.The antifungal activity of six kinds of agricultural pathogenic fungi has different degrees of inhibition.3、The structure of 4-methoxy salicylaldehyde is modified to produce a total of 26 compounds,and 20 new compounds.From the point of view of molecular structure,the antibacterial effect of the derivatives of-OH and-CHO on the skeleton of the compound was decreased,which indicated that the two groups of-OH and-CHO play an important role in the antibacterial activity,in which the-OH group of 4-methoxysalicylaldehyde has a greater effect on the antibacterial activity.While the change in insecticidal activity is only related to-OH.To improve the insecticidal activity of the compound has to modify the-CHO group of 4-methoxysalicylaldehyde.It should be noted that to improve the insecticidal activity is not only related to the modification of-CHO,but also to the manner in which-CHO is modified.Therefore,the modification of-CHO needs further investigation.