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【目的】西瓜枯萎病是由西瓜专化型尖孢镰刀菌(Fusarium oxysporum f.sp.niveum)引起的一种常见的毁灭性土传病害,对镰刀菌同属非致病性菌株与致病性菌株存在的竞争作用进行研究,有助于获得新的具有生防效果的菌株,从而拓宽西瓜枯萎病生物防治的手段。【方法】利用选择性培养基和稀释平板计数法对温室盆栽试验中西瓜根际和非根际土壤及植物组织中非致病性轮枝镰刀菌菌株(Fusarium verticillioides XA)与致病性尖孢镰刀菌(Fusarium oxysporum LD)进行计数,确定其在西瓜植株根际和组织中的定殖情况。【结果】将从田间西瓜枯萎病发病植株根部分离获得的菌株XA和LD接入健康土壤中,接种菌株XA既不会引起西瓜枯萎病发病症状,也不会影响西瓜植株生物量,但接种菌株LD导致严重发病症状。与单接种LD处理相比较,双接种(XA+LD)处理地上部鲜重和地上部干重都分别增加了151.2%和110%。XA菌株能成功定殖于西瓜根系,但在茎基部没有检测到。在接种菌株LD的处理中植物组织和土壤中致病性镰刀菌的数量达到(1.58 4.85)×104CFU/g。与单接种LD处理相比,双接种菌株XA和LD处理植物茎基部、根系、根际土壤和土体土壤致病性镰刀菌的数量分别下降63.3%、66.1%、3.3%和24.4%,根系、根际土壤和土体土壤非致病性镰刀菌的数量增加到(0.35 3.84)×104CFU/g;双接种处理对西瓜枯萎病的防效达57.8%。【结论】非致病性轮枝镰刀菌菌株XA可有效降低致病性尖孢镰刀菌LD对西瓜植株的定殖侵染能力,对西瓜枯萎病具有一定的生防效果。
【Objective】 Fusarium wilt of watermelon is a common devastating soil-borne disease caused by Fusarium oxysporum f.sp.niveum, Strain competition exists to study, will help to obtain a new biocontrol strains, thereby broadening the biological control of watermelon blight means. 【Method】 The non-pathogenic Fusarium verticillioides XA and pathogenic spores were isolated from rhizosphere and non-rhizosphere soil and plant tissues of watermelon in greenhouse using selective culture medium and dilution plate counting method. Fusarium oxysporum LD was counted to determine its colonization in watermelon rhizosphere and tissues. 【Result】 The results showed that XA and LD isolated from the roots of Fusarium oxysporum f. Sp. In the field were inoculated into healthy soil. Inoculation with XA did not cause the symptoms of Fusarium oxysporum f. Wilt nor did it affect the biomass of watermelon, LD causes severe onset symptoms. Compared with single-inoculation, the fresh weight of shoots and shoot dry weight of double-inoculated (XA + LD) treatments increased by 151.2% and 110% respectively. The XA strain successfully colonized the root of watermelon but was not detected at the base of the stem. The number of pathogenic Fusarium species in plant tissue and soil reached (1.58 4.85) x 104 CFU / g in the inoculated strain LD. Compared with single inoculation with LD, the number of pathogenic Fusarium spp in stem, root, rhizosphere soil and soils decreased by 63.3%, 66.1%, 3.3% and 24.4% , And the number of non-pathogenic Fusarium soils in rhizosphere soil and soil soil increased to (0.35 3.84) × 104CFU / g. The control effect of double inoculation on watermelon fusarium wilt was 57.8%. 【Conclusion】 Non-pathogenic Fusarium verticillum strain XA can effectively reduce the colonization and infestation ability of pathogenic Fusarium oxysporum LD to watermelon plants and has certain biocontrol effect on Fusarium oxysporum f.