| 摘要: |
| 【目的】探索魔芋软腐病株根区、根表土壤及根系大量存在的优势真菌F3和F8是否具有致病性和化感活性；筛选针对该优势真菌及魔芋软腐病原细菌的高效广谱生防放线菌。【方法】从魔芋健株和病株中分离F3和F8菌株，根据菌落形态及rDNA-ITS序列分析对2株真菌进行鉴定；离体侵染法测定菌株对魔芋球茎及胡萝卜离体组织的致病性；测定真菌粗毒素溶液对甜瓜种子萌发、幼苗生长的化感活性；采用琼脂块和发酵滤液法筛选能拮抗优势病原真菌和魔芋软腐病原细菌的生防放线菌。【结果】①在魔芋软腐病株根区、根表土壤及根系中存在大量的F3和F8，经鉴定，2株真菌分别为腐皮镰刀菌（Fusarium solani）和尖孢镰刀菌（Fusarium oxysporum），其发酵粗滤液对魔芋离体球茎及胡萝卜有致病性，其粗毒素溶液能抑制甜瓜种子萌发和幼苗生长。②筛选得到6株对优势病原真菌镰刀菌和魔芋软腐病原细菌均有较强拮抗作用的生防放线菌。【结论】魔芋软腐病株根区、根表土壤及根系大量存在的优势真菌腐皮镰刀菌和尖孢镰刀菌具有致病性和化感抑制活性，是魔芋软腐病发生时的复合侵染有害菌之一；以2株镰刀菌为靶标菌筛选到的6株生防放线菌对魔芋软腐病株根域大量存在的优势有害真菌及软腐病原细菌均有较强的拮抗作用。 |
| 关键词: 魔芋 软腐病 腐皮镰刀菌 尖孢镰刀菌 化感作用 复合侵染 |
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| 基金项目:国家林业局重点科技推广项目（魔芋产业化配套技术2010-38）；财政部农业科技体系建设项目(XTG2013-36)；陕西省科学技术研究发展计划项目（2013K02-24） |
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| Identification and allelopathic effect of dominant fungi in rootzone of Amorphophallus konjac and screening of the bio-control actinomycetes |
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HE Fei,ZHANG Zhongliang,CUI Ming,et al
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| Abstract: |
| 【Objective】Dominant fungi F3 and F8 were obtained from rhizosphere soil,rhizoplane soil,and root of soft rot-infected Amorphophallus konjac plants and their pathogenicity and allelopathic activities were tested.Efficient and broad spectrum biocontrol actinomycetes with conspicuous antagonistic effect on dominant fungi and pathogenic bacteria were also screened.【Method】Strains F3 and F8 isolated from diseased and healthy A.konjac plants were identified according to colony morphology and rDNA-ITS sequence analysis.Infection test in vitro was used to determine the pathogenicity on A.konjac and carrot tissues.Melon seed germination experiments were conducted to investigate the allelopathic activity.Antagonistic bio control actinomycetes against dominant fungi and pathogenic bacteria were screened by agar block and fermentation filtrate.【Result】① A large number of F3 and F8 existed in rhizosphere soil,rhizoplane soil and root of soft rot-infected A.konjac plants. Isolates F3 and F8 were identified as Fusarium solani and Fusarium oxysporum.Their crude filtrates of fermentation were pathogenic to A.konjac corms and carrot tissues.Their crude toxin solutions also had inhibition effects on seed germination and growth of melon seedlings.②Six bio-cotrol actinomycetes were screened with strong antagonistic activity against dominant Fusarium and soft rot pathogenic bacteria of A.konjac.【Conclusion】Dominant fungi Fusarium solani and Fusarium oxysporum found abundantly in rhizosphere soil,rhizoplane soil and root of diseased A.konjac had pathogenic and allelopathic activities.Six antagonistic bio-control actinomycetes were screened against dominant Fusarium and soft rot pathogenic bacteria of A.konjac. |
| Key words: Amorphophallus konjac soft rot disease Fusarium solani Fusarium oxysporum allelopathic effect composite infection |
