Conclusions
In conclusion, single or co-inoculated the two bacterial
strains, B. subtilis and P. fluorescens, to greenhouse
tomato seedlings under reduced chemical N conditions enhanced plant growth, improved the control
efficiency of gray mold disease, and exhibited a
characteristic of PGPR. qPCR results proved that
10 days after inoculation, the two bacterial strains
could survive in rhizosphere soil. Biolog and PCRDGGE methods were used to evaluate the soil
microbial communities. Different AWCD trends
and DGGE patterns were got in different bacterial
treatments; however, analyses of microbial diversities
showed that indigenous soil microbes did not seem to
have significant differences at either the catabolic or
genetic level among treatments. ETS, as a commercial
microbial agent, promoted plant growth and gave a
higher microbial diversity in rhizosphere soil. The
characteristics of the two bacterial strains to promote
growth and control disease in greenhouse tomato might
be due to other mechanisms, such as ACC-deaminase
activity, P-solubilization and chitinase production.