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The mechanism of disease development in pine wilt

松材线虫病发病机制

基本信息

批准号：
01560164
负责人：
FUTAI K.
金额：
$ 1.66万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

项目摘要

Substances associated with tissue browning of Japanese red(Pinus densiflora)and black pine(P. -thunbergii)inoculated with pinewood nematode(Bursaphelenchus xylophilus)were identified to be some kind of polyphenolics. A catechin-like substance was the most abundant polyphenolic associated with large numbers of B. xylophilus. Catechin, a tannin monomer was detrimental to the reproduction of B. xylophilus and its relative non-pathogenic species, B. mucronatus. Tannin increased conspicuously in field-planted seedlings when they were inoculated with B. xylophilus, thereby they seem to resist pinewood nematode invasion.Water content, amount of tannin, transpiration rate and nematode distribution were determined for pinewood nematode-inoculated, potted seedlings of Japanese black pine which were watered daily or every-fourth day. Multiple regression analysis revealed negative correlations. between water content of wood tissue and nematode numbers in specific stem segment, suggesting an important causal relation between these two factors. In the following experiment, a significant positive correlation was observed between nematode numbers and amounts of(i)oxidized lipids, (ii)tannin and(iii)leachates at 7, 7 and 14 days after inoculation, respectively. There was also a significant positive correlation between the amounts of leachates and tannin 14 days after inoculation. The results bring us the following hypothesis that generation of super oxide anion or hyperaccumulation of tannin, or both may cause leakage of abnormal substances from parenchyma cells, and the substances plug tracheids, thereby causes host wilting.

经鉴定，与松材线虫（Bursaphelenchusxylophilus）侵染赤松（Pinusdensiflora）和黑松（P. -thunbernalus）的组织布朗宁有关的物质是多酚类物质。儿茶素样物质是与大量B相关的最丰富的多酚。木生植物单宁单体儿茶素对B的繁殖不利。木虱属及其近缘非致病种，B. mucronatus接种B后，大田幼苗单宁含量显著增加。以接种松材线虫的日本黑松盆栽苗为材料，每天或每隔4天浇水，测定其含水量、单宁含量、蒸腾速率和线虫分布。多元回归分析显示负相关。木材组织含水量与特定茎段线虫数量之间存在着重要的因果关系。在下面的实验中，线虫数量和（i）氧化脂质，（ii）单宁和（iii）浸出物的量之间观察到显着的正相关性，分别在接种后7，7和14天。接种后14天，淋滤液量与单宁含量呈显著正相关。结果提示，超氧阴离子的产生或单宁的过度积累，或两者共同作用，可能导致薄壁细胞异常物质的渗漏，堵塞管胞，从而引起寄主萎蔫。