한국 들잔디에 발생하는 Rhizoctonia solani에 의한 라지패치를 생물학적으로 방제하기위해 일반토양에서 길항미생물을 분리하여 in vitro와 in vivo에서 길항효과 및 병 발생억제효과를 검정하였다. 토양에서 분리한 216개 균주 중 15개 균주가 R. solani AG2-2 (IV)의 균사생장을 70%이상 억제하였으며, 온실실험 결과 11개 균주는 잔디의 생장을 촉진시켰으며, 병 발생 억제효과가 있었다. 분리한 길항미생물 중 H33 균주는 in vitro 및 in vivo에서 R. solani AG2-2 (IV)에 대한 길항효과가 다른 균주에 비해 높았으며, 공시한 17개 식물병원성 진균에 대해 길항효과가 높아 생물방제균으로 선발하였다. H33 균주를 ISP 배지에 배양한 후 배양적 특성 및 형태를 관찰한 결과 Streptomyces sp.로 동정되었으며, 16S rDNA를 분석한 결과 Streptomyces arenae와 99% 상동성을 보였다.
The objective of this study was to identify bacterial antagonists of R. solani AG2-2 (IV) on zoysiagrass and to evaluate their antifungal activity in vitro and in vivo to select an antagonistic isolate. Antagonistic isolates that inhibit large patch disease caused by R. solani AG2-2 (IV) in zoysiagrass were selected from several soils, and their antagonistic activities were investigated in vitro and in vivo. Of 216 bacterial isolates, 67 inhibited several plant pathogenic fungi. The isolates that inhibited stem-segment colonization by R. solani AG2-2 (IV) in zoysiagrass were tested in a growth chamber. Eleven isolates were active as plant growth promoting isolates. Among them, five plant growth promoting isolates and their concentration dependent efficiency on zoysiagrass following inoculation with R. solani AG2-2 (IV) was evaluated. Isolate H33 was one of the potential antagonistic isolates, and it was further tested against various plant pathogens. H33 not only suppressed the disease caused by R. solani AG2-2 (IV) on zoysiagrass but also promoted leaf weight and leaf height of zoysiagrass under growth chamber and greenhouse conditions. The H33 isolate, which belongs to Streptomyces arenae, was identified through physiological, biochemical, and 16S rDNA studies. Further studies will investigate the cultural characterization of S. arenae H33 and isolation and identification of antifungal substance produced by S. arenae H33.
