红三叶根际促生菌中具生防效果菌株筛选、鉴定及特性研究

【目的】从岷山红三叶根际分离的109株促生菌，鉴定、筛选了具有生防能力的菌种资源并研究其生防特性，为生产应用提供服务。【方法】采用平板对峙法筛选优良生防菌株，对其产铁载体能力进行定性、定量测定和16S rRNA基因序列分析鉴定。【结果】平板对峙试验显示，109株促生菌中有8株促生菌对3种病原真菌 (立枯丝核菌、黄瓜枯萎菌、西瓜尖镰孢菌) 具有拮抗效果，分别是菌株MHS3、MHS7、MHS9、MHS27、MHS31、MHS38、MHS39和MHS48。其中，菌株MHS27、MHS31发酵液对立枯丝核菌抑菌率分别为40.1%、47.1%；菌株MHS7和MHS48发酵液对黄瓜枯萎菌抑菌率分别为26.1%、22.8%；菌株MHS27和MHS31发酵液对西瓜尖镰孢菌抑制率分别为34.0%、30.5%；产嗜铁素是生防菌 (MHS7、MHS27、MHS31、MHS48) 拮抗3种病原真菌的主要途径之一。经16S rRNA基因序列分析初步鉴定，菌株MHS7为特基拉芽孢杆菌 (Bacillus tequilensis)，菌株MHS27为溶蛋白芽孢杆菌 (Bacillus proteolyticus)，菌株MHS31为Pseudomonas paralactis，菌株MHS48为克雷伯氏菌 (Klebsiella oxytoca)。【结论】从岷山红三叶根际分离筛选出4株具有优良生防作用的PGPR菌株，为今后生物菌肥应用推广提供了菌种资源支持。

Screening,identification and characterization of biocontrol bacteria from PGPR in Trifolium pretense

【Objectives】Biocontrol bacteria were screened from 109 strains of plant growth promoting rhizobacteria (PGPR) of Trifolium pratense in Minshan. Their promoting effects were identified and their biocontrol characteristics were studied for the practical use.【Methods】The plate confrontation method was used to screen the excellent biocontrol strains, and siderophore producing capacity of the strains was measured and the 16S rRNA gene sequence of these strains was analyzed.【Results】Eight strains of biocontrol bacteria showed an antagonistic effect on 3 pathogenic fungus (Rhizoctonia solani, Fusarium oxysporium f. sp. Cucumerinum, and Fusarium oxysporum f. Niveum). The strains were MHS3, MHS7, MHS9, MHS27, MHS31, MHS38, MHS39 and MHS48, and among them, the inhibition rates of the strains of MHS27 and MHS31 against Rhizoctonia solani were 40.1% and 47.1%, the inhibition rates of the strains of MHS7 and MHS48 against Fusarium oxysporium f. sp. Cucumerinum were 26.1% and 22.8%, and the inhibition rates of the strains of MHS27 and MHS31 against Fusarium oxysporum f. Niveum were 34.0% and 30.5%. The siderophore produced was one of the main ways to antagonize 3 pathogenic fungi in biocontrol bacteria (MHS7, MHS27, MHS31, MHS48). The results of the 16S rRNA gene sequence analysis showed that the strain MHS7 was Bacillus tequilensis, the strain MHS27 was Bacillus proteolyticus, the strain MHS31 was Pseudomonas paralactis, and the strain MHS48 was Klebsiella oxytoca.【Conclusions】These four excellent PGPR strains which were screened from the Trifolium pretense rhizosphere of Minshan can provide a support for the application of bio-fertilizer in the future.