Molecular elucidation of elicitors and suppressors in rice blast disease by using as the marker the Sekiguchi lesion formation in lesion mimic mutants

以病斑模拟突变体中的关口病斑形成为标记，对稻瘟病中的引发子和抑制子进行分子阐明

基本信息

批准号：
12660046
负责人：
ARASE Sakae
金额：
$ 2.37万
依托单位：
Shimane University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

An antifungal compound with an infection-inhibiting activity was isolated from a rice Sekiguchi lesion (sl) mutant and identified as the indole alkaloid tryptamine. Tryptamine inhibited not only spore germination and appressorium formation of M.grisea at high concentrations (>600 μg/ml) but also the infection hypha formation in onion cells at low concentrations (150-300 μg/ml). Tryptamine is a normal compound of the rice sl mutant but accumulates further in rice with a mutant-type response (Sekiguchi lesion formation) to inoculation with M.grisea spores. A mutant type of response is involved in light-enhanced resistance. The accumulation of tryptamine was not induced, however, in rice with a wild-type response (blast lesion formation). This study strongly suggests that tryptamine plays an important role as a possible factor in light-enhanced resistance in the rice sl-mutants. Increased activities of tryptophan decarboxylase (TDC) and monoamine oxidase (MAO) were light-dependent and obs … More erved in sl-mutant of rice infected with M.grisea. TDC and MAO activites were already observed before penetration of M.grisea to rice cells and kept at high level even after Sekiguchi lesion formation. Spore germination fluid of M.grisea also induced the Sekiguchi lesion formation with increased activites of both enzymes activities and tryptamine accumulation. Sekiguchi lesion was also induced by the treatments with tryptamine and β-phenylethylamine, which are substrates for MAO, under the light, but not induced by non-substrates such as indole-3-propionic acid, (^^+___)-phenylethylamine and tryptophan even under the light. Light-dependent induction of Sekiguchi lesion by tryptamine was significantly inhibited in the presence of MAO inhibitors, metalaxyl and semicarbazide, and H_2O_2-scavengers, ascorbic acid and catalase. H_2O_2 in leaves with Sekiguchi lesion was demonstrated directly in situ by strong DAB staining. On the other hand, H_2O_2 induced Sekiguchi lesion on leaves of cv. Sekiguchi-asahi under the light, but not under the dark. This difference was associated with decrease of the catalase activity in infected leaves under the light and no decrease under the dark. We hypothesize that H_2O_2-induced breakdown of cellular organelles such as chloroplast and mitochondria in mesophtll cells may bring about high activities of TDC and MAO and development of Sekiguchi lesion, and that the Sl gene products in wild type rice may function as a suppressor of organelle breakdown cased by chemical or environmental stress. Less

具有感染感染活性的抗真菌化合物是从水稻的病变（SL）突变体中分离出来的。同样，在低浓度（150-300μg/mL）中，洋葱细胞中的感染菌丝形成，在水稻中以突变体型反应（sekiguchi病变形成）在水稻中进行粘液。，在带有威尔德型呼吸的RIC中（BLAST病变形成）强烈地表明，色胺在稻米中的光增强中起着重要的作用。观察……在大米的sl中，与M.grisea相连。还诱导了sekiguchi病变形成，其激活源增加了激活剂和色氨酸的积累。 D在黑暗下，这是在光线下的过氧化氢酶活性下降的范围野生型水稻中的插槽可能是通过化学或环境应力降低的Asuppressor Organel分解。