Study On The Toxin Composition Of Alternaria Gaisen And Antibacterial Active Ingredients In Jujube Wood Vinegar

The study isolated and identified secondary metabolites of A.gaisen from a field of Korla fragrant pears,and analyzed the production of toxin by cultivating different nutrient substrates.According to literature research,wood vinegar has good antibacterial activity.The study used wood vinegar to study the antibacterial activity of A.gaisen,and initially obtained the inhibition mechanism of wood vinegar against A.gaisen.Through the separation and identification of the secondary metabolites of A.gaisen,Six compounds were isolated and identified as alternuene(1),altenuisol(2),alternariol(3),alternariol methyl ether(4)terrein(5)and 7-amino-1,3-dihydroxy-propiophen(6)from A.gaisen four of which are toxin components.By comparing the toxin content of A.gaisen using Korla fragrant pear,apple,tomato,potato,rice,oat and other nutrient substrates.It was found that the structure of toxins(compounds 1-4)produced by A.gaisen using different nutrient substrates was the same,but there were significant differences in toxin content.In order to reduce the production of toxins from A.gaisen and prevent its diseases in the field,the antagonistic activity of A.gaisen was studied using wood vinegar made from red date branches.In terms of growth and spore germination,the MIC value of wood vinegar on A.gaisen was 10 ?L/mL,and the influence of A.gaisen morphology was further observed by optical microscope and scanning electron microscope.,With the increase of the volume concentration of wood vinegar solution,the number of spore germination decreased,and eventually there was almost no spore germination;under the electron microscope scan,with the increase of the concentration of wood vinegar solution,the sporangia appeared deformed,and the mycelium appeared thin and Wrinkles,aggregation,swelling,and fracture.In addition,at a volume concentration of 25 ?L / mL,spore production is completely inhibited.Using gas chromatography-mass spectrometry to separate and identify the chemical components of wood vinegar,46 compounds with a total content of 90.3% of the total content of wood vinegar were identified from the wood vinegar.The main substance was(1)2-Methoxy-4methylphenol accounted for(12.11%),(2)4-Ethylguaiacol accounted for(28.84%),(3)2-Methoxy-4-(1-propyl)phenol accounted for(12.34 %).This type of compound accounts for 63.4% of the total amount of wood vinegar.For these three main component compounds and the five compounds purchased(4)Eugenol,(5)Isoeugenol,(6)3-The activity of Methyl eugenol(7)4-allyl veratrole,and(8)2-methoxy-4-vinylphenol against A.gaisen was studied.The 96-well plate method was used to inhibit the growth of mycelium to obtain MICs of 0.4688?L/mL,0.1171 ?L/mL,0.0293 ?L/mL;0.1171 ?L/mL,0.0585 ?L/mL,0.4687 ?L/mL,0.4687 ?L/mL,0.2347?L/mL through the activity comparison of eight monomers,the position of the substituent will cause the difference in antibacterial activity.The activity of propyl substitution is greater than the activity of ethyl than the activity of methyl;the activity of propylene is greater than that of allyl and greater than vinyl,and the position of the substituent of the compound initially will cause a difference in antibacterial activity.