Differences in intensity and specificity of hypersensitive response induction in Nicotiana spp. by INN, INF2A, and INF2B of Phytophthora infestans
Differences in intensity and specificity of hypersensitive response induction in Nicotiana spp. by INN, INF2A, and INF2B of Phytophthora infestans
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DOI：
10.1094/mpmi-18-0183
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发表时间：
2005-03-01
影响因子：
3.5
通讯作者：
Govers, F
中科院分区：
文献类型：
--
作者：
Huitema, E;Vleeshouwers, VGAA;Govers, F
ELICTINS是一类结构相关的蛋白质家族，在植物中诱导过敏反应(HR)，特别是在烟草中。灯盏花素家族由几个类别组成。大多数植物致病卵菌属的种类都能产生特征明确的10 kDa典型启动素(I类)，例如马铃薯和番茄致病疫霉的INF1。两个基因，info2a和info2b，编码一类独特的类elicitin蛋白，也存在于R inestans中。与分泌的I类启动素不同，III类启动素被认为是细胞表面锚定的多肽。对inf2基因的分子特征分析表明，它们广泛存在于疫霉中。并以一个小基因家族的形式出现。此外，利用基因特异性探针进行Southern杂交和Northern杂交，结果表明，在17个不同的致病疫霉菌株中均可检测到info2基因和inf2B基因及其转录本。利用马铃薯X病毒(PVX)载体(农业侵染)和根癌农杆菌瞬时转化试验(农业渗入)，在植物细胞中进行了inf1和inf2基因elicitin结构域的功能性分泌表达，并在烟草中产生了类似HR的坏死症状和诱导了防御反应基因。然而，对INF1、INF2A和INF2B激发子活性的比较分析表明，在HR诱导的强度、特异性和一致性方面存在显著差异。INF1诱导烟草HR，INF2A诱导弱症状，INF2B不诱导症状。然而，与INF1相似，INF2A在本氏新月球藻中诱导HR需要泛素连接酶相关蛋白SGT1。总体而言，这些结果表明烟草抗药性的变异。对R inestans的反应因对干扰素的反应变化而黯然失色。烟草对INF2B的反应能力可以解释观察到的这两个物种对致病疫霉的不同抗性。
Elicitins form a family of structurally related proteins that induce the hypersensitive response (HR) in plants, particularly Nicotiana spp. The elicitin family is composed of several classes. Most species of the plant-pathogenic oomycete genus Phytophthora produce the well-characterized 10-kDa canonical elicitins (class I), such as INF1 of the potato and tomato pathogen Phytophthora infestans. Two genes, inf2A and inf2B, encoding a distinct class (class III) of elicitin-like proteins, also occur in R infestans. Unlike secreted class I elicitins, class III elicitins are thought to be cell-surface-anchored polypeptides. Molecular characterization of the inf2 genes indicated that they are widespread in Phytophthora spp. and occur as a small gene family. In addition, Southern blot and Northern blot hybridizations using gene-specific probes showed that inf2A and inf2B genes and transcripts can be detected in 17 different P infestans isolates. Functional secreted expression in plant cells of the elicitin domain of the inf1 and inf2 genes was conducted using a binary Potato virus X (PVX) vector (agroinfection) and Agrobacterium tumefaciens transient transformation assays (agroinfiltration), and resulted in HR-like necrotic symptoms and induction of defense response genes in tobacco. However, comparative analyses of elicitor activity of INF1, INF2A, and INF2B revealed significant differences in intensity, specificity, and consistency of HR induction. Whereas INF1 induced the HR in Nicotiana benthamiana, INF2A induced weak symptoms and INF2B induced no symptoms on this plant. Nonetheless, similar to INF1, HR induction by INF2A in N. benthamiana required the ubiquitin ligase-associated protein SGT1. Overall, these results suggest that variation in the resistance of Nicotiana spp. to R infestans is shadowed by variation in the response to INF elicitins. The ability of tobacco, but not N. benthamiana, to respond to INF2B could explain differences in resistance to P infestans observed for these two species.