Abstract:

【Objective】 The objective of this study was to investigate the influence of biocontrol agent Pseudomonas fluorescens 2P24 on microecosystem in the rhizosphere of melon, and to provide biosafety evaluation for the application of the bioagent. 【Method】 The influence of biocontrol agent 2P24 on microecosystem in melon rhizosphere at different growing stages was investigated by using plate culture and terminal restriction fragment length polymorphism (T-RFLP) analysis. 【Result】 After transplantion, the rhizosphere biomass of bacteria and fungi in the strain 2P24-treated melon seedlings was decreased, while the population of actinomycetes was increased. In the harvest period, the influence of strain 2P24 on bacteria and actinomycetes was not significant, but the fungal population was promoted obviously. Totally 41 TRFs were obtained by T-RFLP analysis, among which the dominant floras of TRF213, TRF240 and TRF513 were not obviously affected, while the floras of TRF61, TRF348 and TRF365 were influenced significantly, which was also validated by the increased biodiversity indices (Shannon-Wiener). 【Conclusion】 The abundance bioinformation on the influence of strain 2P24 on microbial diversity was obtained by the methods combined with plate cultivation and T-RFLP analysis, and the results showed that the biocontrol agent 2P24 did not significantly affect the diversity and dynamics of microbial communities in melon rhizosphere.

Key words: biocontrol agent Pseudomonas fluorescens 2P24, rhizosphere microorganism, T-RFLP