生防外生菌根真菌的筛选及其生长和发酵条件优化

Screening of Antagonistic Ectomycorrhizal Fungi and Optimization of Growth and Fermentation Conditions

为了筛选具有广谱拮抗活性的外生菌根真菌,采用平板对峙法(初筛)和生长速率法(复筛)测定了6种外生菌根真菌对5种常见植物病原真菌的抑制活性,通过单因素试验对抑制效果较好的生防菌进行生长及发酵条件优化。结果表明,彩色豆马勃Pt01在初筛试验中对植物病原真菌的抑菌率为40.1%~49.7%,在复筛试验中抑菌率为78.5%~91.8%,抑菌作用整体高于其他外生菌根真菌。条件优化后发现,Pt01在28℃、p H值为7.0、碳源为乳糖、氮源为硝酸钾时生长最好;其最佳发酵条件:温度为30℃,初始p H值为6.0,碳源为乳糖,氮源为酵母膏,时间为5 d,转速对不同病原真菌抑菌率各有不同影响,需要单独考虑最佳转速。彩色豆马勃菌株Pt01对5种受试病原真菌均有明显的抑制作用,优化其生长和发酵条件为其在植物病害防治上的应用提供了理论依据。

In order to screen ectomycorrhizal fungi with a broad spectrum of antagonistic activity, the dual culture assay and growth rate method were performed for determining the inhibitory efficacy of six ectomycorrhizal fungi against five kinds of common plant pathogenic fungi. Subsequently, the growth and fermentation conditions of the strain with a higher inhibitory rate to pathogenic fungi were optimized through the single factor experiment. The results showed that Pisolithus tinctorius PtOl had a better inhibitory efficacy against all the plant pathogenic fungi. In confrontation cul ture, the inhibitory rates of PtOl against five kinds of plant pathogenic fungi were from 40. 1% to 49. 7% , while the inhibitory rates were from 78.5% to 91.8% with growth rate method. After optimized, the growth conditions of PtOl were temperature of 28 °C ,initial pH of 7. 0,lactose as carbon source,and potassium nitrate as nitrogen source. Additionally, the optimum fermentation conditions of PtOl were temperature of 30 °C , initial pH of 6. 0 , lactose as carbon source, yeast extract as nitrogen source, fermentation time of 5 d. The highest inhibitory rates of PtOl to different pathogenic fungi were obtained at different rotational speed, so rotational speed was necessary to be considered separately for achieving the best inhibitory effect. These results demonstrated that PtOl had obvious inhibition against five kinds of pathogenic fungi,and the optimization of its growth and fermentation conditions could provide theoretical basis for its application in the prevention and control of plant diseases.