河西走廊盐碱土壤中抗立枯丝核菌的放线菌筛选

Screening of Actinomyces on Antagonism to Rhizoctonia solani Isolated from Saline-alkali Soils in Hexi Corridor

从甘肃省河西走廊盐碱土中分离所得50株放线菌中,筛选出对立枯丝核菌有生防潜能的放线菌,旨在为生物防治作物病害提供新的菌种资源。通过平板对峙法、生长速率法及活体组织法筛选拮抗菌,并对其进行形态及分子鉴定。经过平板初筛,有4株菌株对立枯丝核菌有拮抗作用,编号Ⅰ18-5-2、Ⅲ22-3-12、Ⅳ16-3-2、DC009-1-23,其中Ⅳ16-3-2和DC009-1-23有较高的拮抗性,抑菌圈直径分别为20.5 mm和15.5 mm;进而对这2菌株进行发酵液复筛,菌丝的生长抑制率分别为89.02%和80.49%;活体组织试验表明,Ⅳ16-3-2和DC009-1-23对立枯丝核菌的防治效果分别达54.29%和45.71%;通过形态培养特征和16S rDNA序列鉴定,将菌株Ⅳ16-3-2初步鉴定为变异链霉菌,DC009-1-23为丁香链霉菌。

This study selected several actinomycetes from 50 strains of the saline-alkali soils of Hexi Corridor in Gansu Province which have been proved to be resistant to Rhizoctonia solani by antagonistic test, which would provide new strains resources in crop disease control. Pair culture method, growth rate method and tissue culture method were used to select antagonistic bacteria. The results of antagonistic test showed that there were 4 strains with antagonism to Rhizoctonia solani, which were named [ 18-5-2,Ⅲ 22-3-12, 1V 16-3-2 and DC009-1-23. From above four strains, IV 16-3-2 and DC009-1-23 had a higher antagonism and the diameters of inhibiting bacteria circle were 20.5 mm and 15.5 mm. By resereening these two strains with higher antagonism from fermentation broth, the result showed that their mycelial growth inhibition rates were 89.02% and 80.49%. Biopsy tests showed that the control efficiency of IV 16,3-2 and DC009-1-23 to Rhizoctonia solani reached 54.29% and 45.71%, respectively. According to morphological characteristic and phylogenetic analysis based on 16S rRNA gene sequence, the strain IV 16-3-2 was preliminarily identified to be StreDtomces variabilis while the strain DC009-1-23 was identified to be StreDtomces lilaceus.