Evaluation of populations of fluorescent pseudomonads related to decline of take-all patch on turfgrass
Evaluation of populations of fluorescent pseudomonads related to decline of take-all patch on turfgrass
复制标题
与草坪全食斑块衰退相关的荧光假单胞菌种群评价
作者：
A. Sarniguet;P. Lucas
由全麦酵母菌（Gaeumannomyces graminis var.）引起的草坪草全食。燕麦（Gga）以淡黄色植物的形式出现。在一些斑块上，中心区域重新被相同的草种羊茅属（Festuca sp.）占据，尽管该疾病呈离心扩展，但该草种先前已被真菌破坏。这种疾病的缓解被理解为衰退。根际细菌计数显示，斑块所有区域的细菌总数几乎相同。而无病区、斑块前缘、斑块受损部分和重新定植的中心部分荧光假单胞菌/总细菌的比例分别为1/22、1/15.4、1/3.5和1/2.9。此外，在最后提到的区域中，44% 至 82% 的荧光假单胞菌属。体外对 Gga 呈拮抗作用，而来自无病区的仅 12% 至 34% 呈拮抗作用。因此，草坪上全食的发展引起了荧光假单胞菌种群数量和质量的变化。中心疾病的缓解与这部分斑块中较高数量的拮抗性荧光假单胞菌相关。这种具有明确区域的典型斑块可以为研究与全食下降相关的细菌种群变化提供良好的模型。
Take-all on turfgrass caused by Gaeumannomyces graminis var. avenae (Gga) occurs as patches of yellowish plants. On some patches the central zone was recolonized by the same grass species, Festuca sp., previously damaged by the fungus despite the centrifugal extension of the disease. This disease remission was assimilated to decline. Rhizosphere bacterial counts showed that total population of bacteria was nearly the same in all zones across the patches. However, the ratio of fluorescent Pseudomonas spp./ total bacteria was 1/22, 1/15.4, 1/3.5 and 1/2.9 in the disease free area, the front margin of the patch, in the damaged part of the patch, and in the recolonized central part respectively. Furthermore, in this last mentioned zone, 44 to 82% of the fluorescent Pseudomonas spp. were antagonistic in vitro to Gga, whereas only 12 to 34% from the disease free area were antagonistic. So the development of take-all on turf induced quantitative and qualitative changes in populations of fluorescent pseudomonads. The remission of the disease in the center was correlated to higher amount of antagonistic fluorescent pseudomonads in this part of the patches. This typical patch with the well defined zones can provide a good model for the study of changes in bacterial populations related to the build up of take-all decline.