特殊生境中植物枯、黄萎病拮抗放线菌的筛选及鉴定

Screening and identification of antagonistic actinomycetes on Fusarium oxysporiumand Verticillium dahliafrom special habitats

【目的】从特殊生境中分离筛选对植物枯、黄萎病具有较高生防活性的土壤放线菌,为深入开展枯、黄萎病的生物防治提供高效菌株。【方法】用平板稀释法,从采自广西、江苏、陕西等地特殊生境的5份土壤样品中分离放线菌;以西瓜枯萎菌、茄子黄萎菌、棉花枯萎菌作为靶标菌,通过平板对峙法进行初筛和复筛;采用菌丝生长速率法、水琼脂平板法,测定入选菌株发酵液的活性,并对其中拮抗活性高的菌株进行形态特征、培养特征及生理生化特性的分析鉴定,初步确定其分类地位。【结果】从5份采自特殊生境的土壤样品中共分离出53株放线菌,并从中筛选出JSC14、GXW1、GXC1、JSW5、JSW7等5株对所有靶标菌都有明显拮抗效果的菌株,其中JSC14菌株发酵液抑菌作用最强。对5株菌发酵液抑菌活性的测定结果表明,JSC14和GXW1菌株发酵液对供试病原菌菌丝生长和孢子萌发均有强烈的抑制作用,菌丝生长抑制率为62.98%～95.38%,孢子萌发抑制率为69.52%～100.0%。经初步鉴定,菌株JSC14为链霉菌属白孢类群白色亚群白色链霉菌(Streptomyces albus),菌株GXW1为拟诺卡氏菌属链孢拟诺卡氏菌(Nocardiopsis streptosporus)。【结论】获得2株对植物枯、黄萎菌有较高生防活性的土壤放线菌,为进一步探讨利用特殊生境中的放线菌控制土传病害提供了研究材料。

【Objective】 The research was in order to obtain soil actionmycetes with high biocontrol activity agaist Fusarium and Verticillium Wilt from special habitats.【Method】 Actionmycetes were isolated from five soil samples collected from special habitats in Guangxi,Jiangsu and Shaanxi through dilution plate method;using Fusarium oxysporium f.sp.niveum,Verticillium dahlia and Fusarium oxysporium f.sp.vasinfectum as target pathogens,the isolates were screened and re-screened in dual cultures;Activities of fermentation broth of the antagonistic strains were determined by using growth rate method and agar plate method,and the high activity strains of them were identified on the basis of morphological,cultural,physiological and biochemical characteristics.【Result】 53 agents were isolated from 5 soil samples in total,and 5 strains out of the 53 isolates showed obvious antagonistic effect on all target pathogens,which were designated as JSC14,GXW1,GXC1,JSW5 and JSW7,and strain JSC14 was the strongest.The activities test of fermentation broth of the 5 antagonistic strains showed that the strain JSC14 and strain GXW1 had significant inhibiting effect on both mycelium growth and conidia germination of target pathogens,Inhibition rates of mycelium growth were 62.98%-95.38%,and inhibition rates of conidial germination were 69.52%-100.0%.In addition,the strain JSC14 was initially identified as Streptomyces albus,and the strain GXW1 belonged to Nocardiopsis streptosporus.【Conclusion】 2 high biocontrol activity actionmycetes were obtained,which enriched the research materials for further studies on controlling plant soil-born diseases with biocontrol actionmycetes from special habitats.