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探讨了生防菌荧光假单胞菌Pseudomonas fluorescens CPF-10对西瓜根围土壤真菌群落结构的影响。采用传统分离培养法,结合变性梯度凝胶电泳(DGGE)分析,研究了施用CPF-10后不同生育期西瓜根围土壤真菌群落结构的变化。结果表明:施入生防菌CPF-10后2周,其对土壤真菌有一定的促进作用;第3～7周时,CPF-10对土壤真菌尤其是部分病原菌有较强的抑制作用;CPF-10对丛枝菌根真菌(AMF)有一定的促进作用,可维持3周左右;收获期后则检测不到CPF-10对土壤真菌群落的影响。生防菌CPF-10对西瓜根围土壤真菌群落产生的短暂影响不会对土壤生态系统构成长期威胁。对比土著真菌及丛枝菌根真菌的DGGE图谱和切胶条带测序结果,发现DGGE技术更适用于分析小范围特定菌属如丛枝菌根真菌的变化。
The effects of biocontrol agent Pseudomonas fluorescens CPF-10 on the fungal community structure in the rhizosphere of watermelon were discussed. The changes of the fungal community structure in the watermelon rhizosphere soils at different growth stages after applying CPF-10 were studied by using traditional isolation and culture methods combined with denaturing gradient gel electrophoresis (DGGE). The results showed that CPF-10 had a strong inhibitory effect on soil fungi at 2 weeks after application of biocontrol agent CPF-10. CPF-10 had a stronger inhibitory effect on soil fungi, especially some pathogens, at 3 to 7 weeks. CPF -10 had some promotion effect on arbuscular mycorrhizal fungi (AMF), which could be maintained for about 3 weeks; after harvest, the effect of CPF-10 on soil fungal community was not detected. The short-term effect of biocontrol bacteria CPF-10 on soil fungal communities in the rhizosphere of watermelon does not pose a long-term threat to soil ecosystems. Comparing the DGGE profiles of the indigenous fungi and the arbuscular mycorrhizal fungi, we found that the DGGE technique is more suitable for the analysis of the changes of the mycorrhizal fungi such as arbuscular mycorrhizal fungi.