Research On The 10.5 Billion Cfu/g Of Mixture For Paenibacillus Polymyxa And Bacillus Subtilis Wettable Powder

With the increasing attention of pesticide residue problem,the demand for microbial fungicides is growing.Microbial bacillus agents have become an important component of biological control because of their green safety and effectiveness.As a main form of microbial bacillus formulation,wettable powder has been registered with a variety of single-bacillus wettable powder,but there is still rare in the registration for bacillus mixture wettable powder.In this paper,10.5 billion cfu/g of mixture for Paenibacillus polymyxa and Bacillus subtilis wettable powder was developed,it contains P.polymyxa and B.subtilis as the main active ingredients.And the active ingredients of the wettable powder was studied in some areas,including culture characteristics,fermentation culture techniques,carrier and additives selecting,mechanism of actions,and field application.The main achievements are as followed:1.By orthogonal test,the composition of fermentation medium of P.polymyxa and B.subtilis was optimized with the volume of bacteria as the index,respectively.The optimized ingredient:(1)Liquid fermentation medium of P.polymyxa: 20 g/L corn flour+10 g/L bean flour+0.5 g/L Mg SO4+ K2HPO4+ Ca Cl2;(2)Liquid fermentation medium of B.subtilis: 10 g/L corn flour + maltose +30 g/Lbean flour+1.5 g/L Ca CO3;After optimized,fermentation volume of P.polymyxa can reaches 5.5×108 cfu/m L,fermentation volume of B.subtilis can reaches 1.04×1010 cfu/m L.2.Based on the fermentation medium filtrate,selected carriers and additves.The wettable powder formula:(1)The wettable powder formula of P.polymyxa(100 g): P.polymyxa fermentation filtrate 205 m L,vermiculite powder 92 g,washing powder 4g,Sodium lignosulfonate 4g,spore amount 1.1×109 cfu/g;(2)The wettable powder formula of B.subtilis(100 g): B.subtilis fermentation filtrate 197 m L,vermiculite powder 92 g,washing powder 4.8 g,Sodium lignosulfonate 3.2 g,spore amount 2.03×1010 cfu/g;Accroding to 1:1,to mix P.polymyxa WP and B.subtilis wettable powder can get 10.5 billion cfu/g of mixture for P.polymyxa and B.subtilis wettable powder.The quality index of wettable powder are as follows: wetting time 53 s,suspension rate 89.9%,p H 7.3,water content 1.5%,fineness 95%,it achieves wettable powder formulation requirements;Accoding to the national standard,an enterprise standard of 10.5 billion cfu/g of mixture for P.polymyxa and B.subtilis wettable powder was developed.3.The 10.5 billion cfu/g of mixture for P.polymyxa and B.subtilis wettable powder was demonstrated that it had good inhibitory effects on tobacco wildfire disease、brownspot disease and targetspot disease by plate inhibition tests and microscopic observation.And 10.5 billion cfu/g of mixture for P.polymyxa and B.subtilis wettable powder can cause damage to tobacco brownspot disease mycelia.And the expression of disease-resistant genes in tobacco,treated with 10.5 billion cfu/g of mixture for P.polymyxa and B.subtilis wettable powder,were determined by real-time fluorescence quantitative PCR.The results showed that our wettable powder can increase expression level of genes obviously,such as MAPKKK、NPR1、PR1、WRKY40 and WRKY70.4.The field test of tobacco results showed that 10.5 billion cfu/g of mixture for P.polymyxa and B.subtilis wettable powder had good control effects on tobacco brown spot disease and wildfire disease,and control effect was 57.62%,69.89% respectly;It had significant control effect on tobacco target spot,and control effect was 78.34%.At the same time,it had no negative effect on the growth and development of tobacco,and it was safe for tobacoo;The agronomic traits of the tobacco treated by the wettable powder were good,and the quality of the fire-cured tobacco leaves were improved.