小麦根系分泌物对西瓜连作土壤真菌群落结构的影响

【目的】研究小麦根系分泌物对西瓜连作土壤中特异性菌群、真菌群落结构和多样性的影响,明确根系分泌物对改善连作土壤微生物环境的作用,为西瓜枯萎病的生态防治和菜田土壤的健康保持提供参考。【方法】本试验以连作3年的西瓜土壤为研究对象,利用土培盆栽试验研究小麦根系分泌物对西瓜连作土壤中真菌群落结构和多样性的影响。【结果】荧光定量结果表明外源添加小麦根系分泌物降低了土壤中总真菌、尖孢镰刀菌和西瓜专化型尖孢镰刀菌的菌群丰度,增加了木霉菌的菌群丰度,且有西瓜苗并添加小麦根系分泌物处理的木霉菌丰度最高,尖孢镰刀菌的丰度最低。无西瓜苗并添加去离子水溶液处理的木霉菌丰度最低,尖孢镰刀菌的丰度最高。在门水平,增加了西瓜连作土壤中壶菌门(Chytridiomycota)的相对丰度,降低了接合菌门(Zygomycota)和担子菌门(Basidiomycota)的相对丰度;在属水平,增加了对病原菌有拮抗作用的毛壳菌属(Chaetomium spp.)和顶孢霉属(Acremonium spp.)的相对丰度,同时降低了有致病潜力的尖孢镰刀菌属(Fusarium spp.)和腐生菌(Humicola spp.)物种的相对...

Effects of Wheat Root Exudates on the Structure of Fungi Community in Continuous Cropping Watermelon Soil

【Objective】 The aim of this paper was to study the effects of wheat root exudates on specific microflora, fungal community structure and diversity in watermelon continuous cropping soils, which was of great theoretical significance to find out the effects of root exudates on the improvement of soil microbial environment, the ecological control of watermelon wilt and the healthy maintenance of vegetable soil. 【Method】 In this experiment, the continuous cropping of watermelon for three years was used as the research object. The effects of wheat root exudates on the structure and diversity of fungal community in watermelon continuous cropping soil were studied by soil culture experiment. 【Result】Re-time PCR results showed that exogenously added wheat root exudates reduced the abundance of total fungal, Fusarium spp. and Fusarium oxysporum f. sp. niveum, but the abundance of Trichoderma spp. was increased in the soils with and without watermelon seedlings. Moreover, the abundance of Trichoderma spp. was the highest under the treatment with watermelon seedlings and exogenous addition of wheat root exudates, but the abundance of Fusarium spp. was the lowest. Trichoderma spp. treated with no watermelon seedlings and added with deionized water solution had the lowest abundance, while Fusarium oxysporum had the highest abundance. At the phylum level, exogenous addition of wheat root exudates increased the relative abundance of Chytridiomycota in the watermelon soils, but reduced the relative abundances of Zygomycota and Basidiomycota in the soils with and without watermelon seedlings. At the genus level, exogenous addition of wheat root exudates increased the relative abundances of Chaetomium and Acremonium spp. in the soils with and without watermelon seedlings, whose species could have pathogen-antagonistic and/or plant-growth-promoting effects. However, exogenously addition wheat root exudates decreased the relative abundances of Fusarium and Humicola spp. in the soils with and without watermelon seedlings, which contained the species that could cause plant pathogens. 【Conclusion】Overall, our results showed that, the change of fungal community in watermelon soil caused by wheat root exudates was one of the reasons why wheat/watermelon slowed down watermelon disease.