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

从小麦、油菜、大白菜和纳皮耶草地土壤中采集的663株大白菜根段中分离到定殖真菌。16个菌株几乎完全抑制根肿病在无菌土壤。在这16个菌株中，两个来自Heteroconium chaetospira的菌株在非无菌土壤中也有效。这两个菌株处理的大白菜幼苗表现出健康，其中一个菌株接种促进生长。利用根内生真菌Heteroconium chaetospira isolate OGR-3诱导大白菜对细菌性叶斑病的抗性，并对其进行了室内盆栽试验。由芸苔链格孢（Alternaria brassicae）引起的斑点落叶病（Alternaria leaf spot）。用H.在生长室中培养毛螺旋体32天。将诱导的幼苗挑战接种P. macuricola或A.芸苔属。与未处理的对照相比，接种的大白菜表现出细菌性叶斑病和链格孢叶斑病的病斑数量显著减少。这表明H. Chaetospira可通过侵染根部诱导叶片系统抗性。

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.