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Cell biology of host resistance to the disease caused by pine-wood nematodes

宿主对松材线虫病害抗性的细胞生物学

基本信息

批准号：
06454088
负责人：
HOGETSU Taizo
金额：
$ 4.61万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06454088/
关键词：
symptom development resistent species induced resistance interaction substance filter experiment age of nematode nematode proliferation early stage of the disease 物質的相互作用皮層樹脂道エピセリウム細胞の破壊柔組織の細胞死剥離樹皮片

项目摘要

1. The role of corical resin canals in the early development of a pine wilt disease in Japanese black pine, pinus thunbergii, was studied. A part of the bark of a 2 cm-long segment from a current-year stem was removed by a tangential cut with a razor blade. Both cortex-exposed segments with cut corical resin canals (deignated as +RC-segments) and those without cut resin canals (-RC-segments) were obtained by chance. When a virulent nematode isolate (S6-1) was inoculated onto the cut surface, the surface of the +RC-segments turned brown 4 d after inoculation, and, in some segments, this browning occurred more intensely around cortical resin canals. When segments were cut transversely at the middle, the transverse cut surface of the inoculated +RC-segments was brown and fragile but that of the inoculated -RC-segments was pale green and stable as the non-inoculated controls. Correspondingly, tissue cells including epithelial cells of the cortical resin canal of the +RC-segments were all d … More ead but those of the -RC-segments were alive as the controls. When nematodes were inoculated onto the inner surface (cambium side) of a bark peeling at which cambial xylem cells were exposed, they did not kill the cambial cells. When inoculated on the transverse cut-end of a bark peeling from which nematodes would enter resin canals, nematodes killed all cells in the peeling. The above results suggest that nematodes do not kill directly cortical cells but become harmful to pine cells after living in cortical resin canals.2. We examined then harmfulness of nematodes at different growth stages and found that nematodes those at older stages do not kill pine cells but those at younger stages do.3. We found by experiments using cortex-exposed segments and filter wells that nematodes at younger stages killed pine cells even but not those at older stages, when filter was inserted between them, preventing nematodes from direct contact with pine tissue. This result means that nematodes at younger stages produce and excrete some killing substances but not those at older stages.4. We examined next the difference in resistance aginst nematodes between Pinus species which are more resistant than P.thunbergii, using cortex-exposed segments and bark peelings of young stems. Cortex-exposed segments and bark peelings of young stems of more resistant species were not killed by nematodes at younger stages, indicating that the resistance is derived from resistance of tissue cells of itself.3. We confirmed resistance induction by preinfection with an avilurent strain of nematode, and studied the mechanism of the resistance induction anatomically. Less

1.研究了松脂导管在黑松枯萎病早期发生发展中的作用。用剃须刀片切掉当年茎上一段2厘米长的树皮的一部分。皮质暴露节段与未切断树脂管的节段(-RC节段)随机分成两组。将一株致病线虫菌株(S6-1)接种到切面上，接种后4d，+RC节段表面发生褐变，部分节段皮质树脂管周围的褐变更为强烈。中部横切时，接种+RC-节段的横切面呈棕黄色，而接种-RC-节段的横切面呈淡绿色，与未接种的对照比较稳定。相应地，+RC节段的组织细胞包括皮质树脂管上皮细胞均为d…更多的EAD，但-RC节段的那些作为对照是活的。将线虫接种到暴露形成层木质部细胞的树皮内表面(形成层一侧)，线虫不会杀死形成层细胞。当接种在树皮剥离的横向切端，线虫从那里进入树脂管道时，线虫杀死了剥离中的所有细胞。上述结果表明，线虫不会直接杀死皮层细胞，而是生活在皮质树脂道中后对松树细胞有害。然后，我们检测了不同生长阶段线虫的危害性，发现年长阶段的线虫不会杀死松树细胞，而年轻阶段的线虫会杀死松树细胞。我们通过使用暴露在皮质的节段和过滤器孔进行的实验发现，当过滤器插入松树细胞之间时，较年轻阶段的线虫甚至会杀死松树细胞，但不会杀死较老阶段的松树细胞，从而防止线虫与松树组织直接接触。这一结果意味着，线虫在较年轻的阶段会产生和排泄一些致死物质，但在较老的阶段则不会产生。接下来，我们使用暴露在皮层的切段和幼茎的树皮，检测了比黑松抗性更强的松种对线虫的抗性差异。在幼龄阶段，抗性较强的树种幼茎的皮层暴露段和树皮未被线虫杀死，说明抗性来源于自身组织细胞的抗性。我们证实了一种线虫新品系通过预感染诱导抗性，并从解剖学上研究了诱导抗性的机制。较少