A gene encoding a protein elicitor of Phytophthora infestans is down-regulated during infection of potato
A gene encoding a protein elicitor of Phytophthora infestans is down-regulated during infection of potato
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DOI：
10.1094/mpmi.1997.10.1.13
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发表时间：
1997-01-01
影响因子：
3.5
通讯作者：
Govers, F
中科院分区：
文献类型：
--
作者：
Kamoun, S;vanWest, P;Govers, F
疫霉属的大多数物种产生10-kDa的胞外蛋白激发子，统称为激发素。激发素在有限数量的植物中诱导过敏反应，特别是在茄科烟草属中。分离并鉴定了茄科植物致病疫霉（Phytophthora infestans）分泌的主要激发素INF 1的cDNA。分析了inf 1基因在致病疫霉发病周期中的表达。INF 1在各种培养基中生长的菌丝体中表达，而在孢子囊孢子、游动孢子、孢囊和萌发孢囊中不表达。在植物中，在马铃薯感染期间，特别是在活体营养阶段，与体外相比，inf 1的表达下调。inf 1的表达水平最高，观察在体外生长的菌丝体，并在感染的后期阶段时，大量的孢子形成和叶片坏死发生。INF 1作为诱导子在I？infestans和Solanum物种进行了调查。测试了代表对致病疫霉具有不同抗性水平的9种茄科物种的19个品系对表达INF 1的大肠杆菌的反应。在茄属内，对致病疫霉的抗性似乎不是由INF 1引起的防御反应介导的。然而，INF 1识别可能是烟草对致病疫霉的非寄主抗性的一个组成部分。
Most species of the genus Phytophthora produce 10-kDa extracellular protein elicitors, collectively termed elicitins. Elicitins induce hypersensitive response in a restricted number of plants, particularly in the genus Nicotiana within the Solanaceae family. A cDNA encoding INF1, the major secreted elicitin of Phytophthora infestans, a pathogen of solanaceous plants, was isolated and characterized. The expression of the corresponding inf1 gene during the disease cycle of P. infestans was analyzed. inf1 was shown to be expressed in mycelium grown in various culture media, whereas it was not expressed in sporangiospores, zoospores, cysts, and germinating cysts. In planta, during infection of potato, particularly during the biotrophic stage, expression of inf1 was down-regulated compared to in vitro. The highest levels of expression of inf1 were observed in in vitro grown mycelium and in late stages of infection when profuse sporulation and leaf necrosis occur. The potential role of INF1 as an elicitor in interactions between I? infestans and Solanum species was investigated. Nineteen lines, representing nine solanaceous species with various levels of resistance to P. infestans, were tested for response to an Escherichia coli expressed INF1. Within the genus Solanum, resistance to P. infestans did not appear to be mediated by a defense response elicited by INF1. However, INF1 recognition could be a component of nonhost resistance of tobacco to P. infestans.