Effects Of Transgenic Microbe On Soil Nematodes

Field release and detection of transgenic Pseudomonas fluorescens strain with Bt Cry genes was investigated. P303N, P303R, Biop8R, Biop8G had similar dynamics of colonization. The population of tested P303N, P303R retained 10~4CFU/g in rhizosphere of soybean within 30 days and 1.34×10~4CFU/g within 60 days;The population of tested Biop8R, Biop8G retained 10~3CFU/g within 30 days and 1.24×10~3CFU/g within 60 days. P303N, P303R, Biop8R, Biop8G had different effect on eggs of Heteodera glycines Ichnohe to some extent. The highest percentage of reduction of eggs is 34.9%, 36.2%, 43.7% and 42.9% by P303N, P303R, Biop8R and Biop8G respectively in field trials. P303N, P303R, Biop8R, Biop8G promoted the height and biology weight of soybean to some extent.In soybean seeding and flowering stage, P303N, P303R, Biop8R and Biop8G release steadily, which has inhibition on plant parasitic nematode. The inhibition of Biop8R and Biop8G are stronger than P303N and P303R. P303N, P303R, Biop8R and Biop8G show different degree of effect in promoting the growth of nonnutritive group of plant nematode. The dominance, quantity and density of Heterodera gfycines and Pratylenchus are lower than the corresponding CK in every treatment from June to August. Biop8R, Biop8G, P303R and P303N have inhibition on Heterodera gfycines and Pratylenchu, but P303R and P303N show lower degree of inhibition than P303R and P303N in the same period.It indicates that Biop8R and Biop8G c an reduce the diversity of ordinary and rare nematode species dramatically during the P303N, P303R, Biop8R and Biop8G steadily releasing period by analyzing soil nematode group mobility, Shannon diversity index (H'), Simpson diversity index (DI), nutritional group diversity index(T). It also indicates that P303N, P303R also can do the same effect but the degree is lower than Biop8R and Biop8G.