Effect Of Bacillus Velezensis YFB3-1 Strain On Earthworm Composting And Control To Rice Seedling Blight

In recent years,rice seedling diseases became more and more serious in the course of the promotion of rice intensive seedling technology and the development of factory plant in China.Rice seedling blight was the main disease during rice intensive seedling and it has caused a large number of seedlings to die,which seriously affected the production of grain safety in our country.Vermicomposting was a promising organic waste treatment technology,which use earthworm to accelerate the compost rate and a large number of beneficial bacteria were found in the earthworm manure.The vermicompost could produce biological organic fertilizer and the beneficial bacteria in the compost have the potential to prevent the transmission of soil-born disease.Vermicompost could also activate soil nutrient and promote the health of the microbe community in the soil.We produce vermicompost with bio-control activity by adding Bacillus velezensis YFB3-1,which was isolated from the intestine of earchworm.The vermicompost with the strain YFB3-1 could effectively prevent the rice seedling bright.The main results are as following.1.Inoculating YFB3-1 could promote both of the number and gross weight of earthworms.The degree of acidity and alkalinity of vermicompost with YFB3-1 was almost neutral and with relative higher content of phosphorus and potassium.The number of bacteria and actinomycete were more abundant in the vermicompost icoculated with YFB3-1.2.YFB3-1 could inhibit several different fungal pathogens of rice seedling bright,such as Fusarium oxysporium,F.solani,F.moniliforme and Rhizoctonia solani.The inhibitory rate against these pathogen agent were more than 70%.In order to clarifying the active substance,we extracted the extracellular components in YFB3-1 broth using ammonium sulfate precipitation method and tested the activity against the pathogen of rice seedling bright.We proposed that the main active substance of YFB3-1 could be bacillomycin and fengycin by comparing genome sequences.3.Treating with vermicompost inoculated with YFB3-1 could prevent the rice seedling bright and improve rice quality at the same time.Vermicompost with YFB3-1 could decrease rice seedling bright more than 41.1% by comparing with common compost.The agronomic characters of rice seedlings were also improved by treating with vermicompost.4.The control effect of YFB3-1 against rice seedling bright was higher than that of Dexon.The results showed that the control efficacy of YFB3-1 and Dexon were 82.2% and41% respectively with treatment followed by pathogen inoculating.The control efficacy of YFB3-1 and Dexon were 57.5% and 34.1% respectively with pathogen inoculating firstly and then followed by the treatment.