Effects of biocontrol agent Pseudomonas fluorescens CPF-10 on soil fungal community in watermelon rhizosphere

The influence of Pseudomonas fluorescens CPF-10 on soil fungal community in watermelon rhizosphere was studied.The traditional culturing method and denaturing gradient gel electrophoresis (DGGE) were used to assess the changes of fungal community at different growth stages of watermelon rhizosphere after application of P.fluorescens CPF-10.During the 1st to 2nd week post-inoculation,CPF-10 showed promoted effect on soil fungi,but it showed strong inhibitory effect on soil fungal community,especially for some pathogens during the 3rd to 7th week post-inoculation.Arbuscular mycorrhizal fungi (AMF) had been promoted to some extent and the effect lasted for 3 weeks.However,the effect of CPF-10 on fungal community was hardly detected during harvest period.The results suggested that the impact of CPF-10 on soil fungal community in the watermelon rhizosphere was short-term,which would not pose a long-term threat to soil ecosystem.Comparing the results of DGGE fingerprints and the sequencing of native fungi and arbuscular mycorrhizal fungi,it was found that DGGE technology was more suitable for analysis of the changes of small and specific community such as arbuscular mycorrhizal fungi.