光叶苕子内生真菌分离鉴定及其对香蕉枯萎病的生防和促生潜力

Isolation and identification of endophytic fungi of Vicia villosa var. and their biocontrol against banana wilt and growth promotion potentials

  • 摘要: 【目的】筛选对香蕉枯萎病具有生防和促生潜力的内生真菌,为香蕉枯萎病的生物防治提供参考依据和潜力菌株。【方法】以香蕉枯萎病菌尖孢镰刀菌4号生理小种热带型(F. oxysporum f. sp. cubense tropical race 4,Foc TR4)为靶标菌,以光叶苕子(Vicia villosa var.)根内分离纯化的内生真菌为试验菌株,采用平板对峙法评价内生真菌对Foc TR4的平板抑制效果;结合形态学与分子生物学方法确定拮抗真菌的分类地位,通过扫描电镜观察拮抗真菌对Foc TR4菌丝形态的影响;并通过平板溶磷圈法、平板固氮圈法和CAS平板法检测拮抗真菌解无机磷、固氮和产铁载体能力;通过盆栽试验验证拮抗真菌对香蕉枯萎病的防治效果及对香蕉的促生效果。【结果】从光叶苕子根部分离纯化得到8株拮抗真菌,其中201、204和401号菌株的抑菌效果最好,经形态学与分子生物学方法分别鉴定为螺卷毛壳菌(Chaetomium cochliodes)、简青霉菌(Penicillium simplicissimum)和蓝状菌(Talaromyces oumae-annae)。平板对峙显示201号菌株对Foc TR4的体外抑制率最高,达74.39%,其次是401号菌株,为71.00%,204号菌株的抑制率为69.83%。扫描电镜观察结果表明3株拮抗真菌均能抑制Foc TR4菌丝生长并导致菌丝畸形,交联变形,且孢子数聚集增多,菌丝明显肿胀,节间缩短,分枝增多,菌丝粗糙,尖端扩张,呈泡状并断裂。204和401号菌株在功能平板上还具有一定的促生潜力,具有解无机磷、固氮和产铁载体能力。盆栽试验结果表明,3株拮抗真菌201、204和401号菌株均对Foc TR4具有较强的抑制活性,并对香蕉枯萎病表现出较好的防治效果,对球茎的防治效果分别为90.625%、65.623%和96.876%,对叶片的防治效果分别为90.745%、90.743%和90.750%,同时,3株拮抗真菌都能在一定范围内减少Foc TR4对香蕉生长的抑制作用,从而促进香蕉植株生长。【结论】从光叶苕子根部分离获得的3株拮抗真菌201、204和401号菌株对香蕉枯萎病菌均有较好的拮抗效果,能抑制香蕉枯萎病菌的毒害,促进香蕉植株生长,具有良好的生防和促生潜力。

     

    Abstract: 【Objective】The purpose of the study was to screen endophytic fungi with biocontrol and growth promotion potentials against banana wilt, and to provide reference basis and potential strains for the biological control of banana wilt. 【Method】Using Fusarium oxysporum f. sp. cubense tropical race 4(Foc TR4) as the target fungus and endophytic fungi isolated and purified from the roots of Vicia villosa var. as the test strains, the plate standoff method was used to evaluate the plate inhibitory effect of the endophytic fungi on Foc TR4. Combining morphology and molecular biology to determine the taxonomic status of the antagonist fungi, the effects of the antagonist fungi on the morphology of Foc TR4mycelium were observed by scanning electron microscopy. The ability of the antagonist fungi to detoxify inorganic phosphorus, fix nitrogen and produce iron carriers was detected by plate phosphorus solubilizing circle method, plate nitrogen fixing circle method and CAS plate method. The biocontrol effect on banana wilt and growth promotion effects of the antagonist fungi on banana were verified by poted test. 【Result】Eight strains of antagonistic fungi were isolated and purified from the roots of V. villosa var., among which strains 201, 204 and 401 had the best inhibitory effect, and were identified by morphology and molecular biology as Chaetomium cochliodes, Penicillium simplicissimum, and Talaromyces oumaeannae. Plate confrontation showed that strain 201 showed the highest in vitro inhibition on Foc TR4 at 74.39%, followed by strain 401 at 71.00% and strain 204 at 69.83%. Scanning electron microscopy results showed that all three strains of antagonistic fungi were able to inhibit mycelial growth of Foc TR4 and lead to mycelial deformity, cross-linking and deformation, as well as increase in spore number aggregation, obvious swelling of mycelium, shortening of internodes, increase in branching, roughness of mycelium, expansion of tips, vesicularity and breakage. Strains 204 and 401 also possessed a certain potential to promote the growth of mycelium on the functional plate, with the capacity of solubilizing inorganic phosphorus, nitrogen fixation and iron carrier production. The potted results showed that all the three antagonistic fungal strains 201, 204 and 401 had strong inhibitory activity against Foc TR4 and showed good control effects against banana wilt with 90.625%, 65.623% and 96.876% on bulbs and 90.745%, 90.743% and 90.750% on leaves, respectively.Meanwhile, all the three strains of the antagonistic fungi were able to reduce the inhibitory effect of Foc TR4 on the growth of banana within a certain range, thus promoting the growth of banana plants. 【Conclusion】The three strains of antagonistic fungi 201, 204 and 401 isolated from the roots of V. villosa var. have good antagonistic effects on banana wilt, can inhibit the virulence of banana wilt and promote the growth of banana plants, and have good potentials of biocontrol and growth promotion.

     

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