Studies On Action Mechanism Of Streptomyces Alboflavus TD-1 Against Botrytis Cinerea

Streptomyces TD-1 had broad-spectrum antibacterial activity which was isolated by our laboratory.In this study,we researched the metabolic rule,inhibitory effect and mechanism against B.cinerea by strain TD-1 in vitro,control efficiency and change of defensive enzymes activity of tomato leaf in vivo.The main results was as follows:The inhibition rate of strain TD-1 against B.cinerea was 87.17%by co-culture on plate.The inhibition rate of TD-1 fermentation broth on radial mycelial growth of B.cinerea by mycelial growth rate method was 98.1%.Inhibitory zone diameter of 15X concentrated solution was 17.75 mm by Oxford cup method.In addition,the inhibition rate to mycelial weight and spore germination against B.cinerea was 83.12%and 98.3%respectively.That showed strain TTD-1 can produce active metabolite against B.cinerea.The antibacterial activity of fermentation broth in Gause's No.1 medium was high and inhibitory zone diameter was 1.47 cm of 10X concentrated solution by screening tests.The study of metabolic rule showed that mycelial wet weight reached maximum in 7th day.The result also suggested that pH range from neutral to alkaline and finally stabilized at about eight.Structure of hyphae was abnormal when observed by optical microscope and electron microscope.after treating by TD-1 fermentation broth.TD-1 fermentation broth could destroy membrane structure of hyphae and spores of B.cinerea by fluorescence microscope.TD-1 fermentation broth increased the mycelial cell membrane permeability and leaded to electrolyte leakage by measuring conductivity.In addition,TD-1 fermentation broth can also effect the membrane structure of B.cinerea by inhibiting ergosterol production.The control efficiency of TD-1 fermentation broth against B.cinerea in tomato fruit and detached leaves was 58.16%and 63.49%respectively in vivo and control efficiency was 76.98%in pot experiment.The activity of PAL,POD,PPO,SOD and CAT in tomato leaves after spraying TD-1 fermentation broth and spore suspension of B.cinerea increased obviously in a certain period of time.They reached maximum in the fourth day,the second day,the third day,the third day,the second day and improved 2.21 times,2.61 times,2.71 times,1.06 times,1.58 times respectively when TD-1 fermentation broth was used as protective agent.They reached maximum in the second day,the fourth day,the third day,the second day,the second day and improved 1.87 times,1.39 times,3.68 times,1.60 times,1.64 times respectively when TD-1 fermentation broth was used as therapeutic agent.TD-1 fermentation broth couldn't harm tomato plants by measuring the content of MDA which was main product of membrane lipid peroxidation.