Studies on suppressive mechanisms against soil borne diseases due to the root endophytic fungus, Heteroconium chaetospira.

从小麦、油菜、白菜和草本植物的土壤中分离到663株白菜根部定植真菌。在无菌土壤中，有16个菌株几乎完全抑制了根瘤病。在这16个菌株中，有两个来自毛细管藻的菌株在非灭菌土壤中也是有效的。用这两个菌株处理的大白菜种子幼苗看起来很健康，接种一个菌株可以促进生长。根内生真菌OGR-3对大白菜根部细菌性叶斑病具有诱导系统抗性的能力。由油菜链格孢菌引起的斑点落叶病和斑点落叶病。用毛细管状螺旋体接种大白菜幼苗，在生长箱中培养32d。诱导出的幼苗用紫丁香P.syringae PV挑战接种。斑点菜属或油菜属。接种大白菜后，白菜细菌性叶斑病和链格孢叶斑病的病斑数较对照明显减少。这说明毛旋毛虫可以通过侵染根部来诱导对叶片的系统抗性。

Root-colonizing fungi were isolated from a total of 663 root segments of Chinese cabbage plants grown in soils collected from wheat, rape, Chinese cabbage, and napier grass fields. Sixteen isolates almost completely suppressed clubroot in sterile soil. Amongst these 16 isolates, two from Heteroconium chaetospira were also effective in nonsterile soil. Chinese cabbage seedlings from seed treated with these two isolates appeared healthy, and inoculation with one isolate promoted growth. Hyphae of the fungus covered the root surface and extensively colonized the inner cortical tissues.The root endophytic fungus, Heteroconium chaetospira isolate OGR-3, was tested for its ability to induce systemic resistance in Chinese cabbage against bacterial leaf spot caused by Pseudomonas syringae pv. macricola and Alternaria leaf spot caused by Alternaria brassicae. Chinese cabbage seedlings inoculated with the isolate of H. chaetospira were incubated in a growth chamber for 32 days. The induced seedlings were challenge inoculated with P. syringae pv. macuricola or A. brassicae. The inoculated Chinese cabbage showed a significant decrease in the lesion number of bacterial leaf spot or Alternaria leaf spot when compared to the non-treated control plants. This indicated that H. chaetospira can induce systemic resistance on foliar by infecting roots.