Screening,Identification And Biocontrol Mechanism Of Antaganism Against Botrytis Cinerea From Tomato

Botrytis cinerea can infect more than 200 kinds of crop species,including important food crops,cash crops and horticultural crops,cause serious worldwide economic losses,especially has a great influence on the temperate regions and subtropical regions.For its fast growth and simple nutritional requirements,Bacillus subtilis has outstanding adventage in disease prevention and control.And Bacillus subtilis can produce spore which has extremely strong resistance to heat and bad environment.It's also easy for Bacillus subtilis to survive,colonize and reproduce in the environment.All these make it good to produce bio-control bacteria agent of Bacillus subtilis.This paper focus on the influence of hypha growth,spore germination,growth and its pathogenic effect by using different concentration gradient of 48 h fermentation filtrate of the bacillus subtilis CQ on Botrytis cinerea.This experient studies on the possible mechanism of CQ inhibiting the growth and development of Botrytis cinerea and reduce pathogenicity.The results of this experient are as follows:1.We obtaine highly active strain Nc6 and CQ through the screening,both of which can inhabit the growth of Botrytis cinerea.Since CQ showed more stable resistance effect,we use CQ as the main subjects in this experiment.By 16 s rDNA sequence alignment,we make sure that highly active strains CQ belong to Bacillus subtilis.And CQ fermentation filtrate has a different degree of inhibition on mycelial growth and morphology,generation of spores,spore germination and germ tube elongation of Botrytis cinerea,among them,and the onion skin infection experiments show that after dealing with the CQ fermentation filtrate,the process of the infection of Botrytis cinerea spores is affected.Higher the concentration of fermentation filtrate,better inhibitory effect has.And temperature and pH have certain influence on CQ: the active ingredient of CQ can stand high temperature,but the activity is greatly reduced when the temperature is more than 100 ?;the active ingredient of CQ can stand certain alkalinity or acidity,but the best pH is around 7.2.The experiments on vitro leaf and plants of tomoto using CQ fermentation filtrate showed good control effects.Compared with control group,CQ bio-control strain fermentation filtrate,Pulvtong and Atailing treatment on tomato plants,enzymes of POD and PAL have significantly improved.The active ingredient of CQ is its extracellular secretion,and through a a series of the purification procedure,the preliminary extraction with antimicrobial activity on Botrytis cinerea was obtained.3.Adding 10 g/L of soluble starch and 0.01 g/L VB2,Arg,Pro on the basis of the LB liquid medium is the most appropriate fermentation medium.The optimal temperature for CQ fermentation is 28 ~ 30 ? while the optimum p H is near 7.And a little oxygen content is needed for CQ in the fermentation process.