松材线虫病致萎毒性物质的研究

The pine wilt disease is one of main diseases found in conifer forests, which leads to wilt and subsequent death of the infected trees. It is mainly distributed in Japan, China and the United States. In addition, it's also found in Canada, Korea, etc. In China, it mainly does damage to black pine ( Pinus thuntergii) and Masson's pine (P. massoniana). Although it was found in Japan in 1905 and research on it has been lasted for more than half a century, its pathogenicity is still not clear. In this project, the origin, identification and pathogenicity of the wilting toxin substance that cause pine wilt in the disease of pine wood nematodes (Bursaphelenchus xylophilus) have been studied. The results showed that the wilting toxin substance could not be produced by pine wood nematodes, but by bacteria carried by nematodes. The bacteria were isolated from the xylem of the wilted black pine and the surface of the nematodes. They are Pseudomonas fluorescens and Pantoea sp. The pathogenic tests in lab conditions indicated that inoculation only with aseptic nematodes wouldn't lead to browning of the callus and wilt of black pine seedlings. But those inoculated with a mixture of the aseptic nematodes and bacteria showed some wilting or browning symptoms. Inoculation in the field with aseptic nematodes would not lead to wilt of 10 years black pine tree either. These revealed the bacteria carried by pine wood nematodes played an important role in pathogenicity. The culture liquid of the bacteria which were used in the treatment of the callus and black pine sidling had an obvious effect on wilting of the treated material. It had been proved that the bacteria could produce wilting toxin substance. The toxin substances were extracted from the xylem of the wilted black pine and Masson's pine had been identified as benzeneacetic acid and 2-methoxycinnamic acid.

松材线虫病是我国森林的毁灭性病害，具有极其危险的流行性。搞清我国主要感病树种-黑松和马尾松上致萎毒性物质的产生、种类和含量变化、作用机制等是提示该病害致病机理的关键。将为进一步开展防治工作提供坚实的生化理论依据；为快速检测和抗病育种找到切实可用的特异性物质及检测方法。本项目是首次在我国进行该病害致萎毒性物质的系统研究。.