Main conclusionGenomic and transcriptomic studies in plants and, more in deep, in grapevine reveal that the disease-resistance RNL gene family is highly variable.AbstractRNLs (RPW8-NLRs) are a phylogenetically distinct class of nucleotide oligomerization domain (NOD)-like receptors (NLRs) identified in plants. Two RNLs, namely, the NRG1 (N Requirement Gene 1) and the ADR1 (Activated Disease Resistance 1), have been characterized; however, little is known about the RNL evolutionary history in higher plants. To trace the diversification of RNL gene subfamily, we scanned the NLR proteins of 73 plant genomes belonging to 29 taxa, revealing a noticeable diversification across species and within the same genus or botanic family together with a conspicuous expansion in important crop species. To explore the RNL variability in Vitis vinifera and gain information with respect to their structure, evolutionary diversification of five grape genomes (‘Aglianico’, ‘Falanghina’, ‘Sultanina’, ‘Tannat’, and ‘Nebbiolo’) has been compared to the reference genome (‘Pinot Noir’). The number of RNLs ranged from 6 (‘Sultanina’) to 14 (‘Nebbiolo’), in contrast to the 10 ‘Pinot Noir’ RNLs. The phylogenetic study on grapevine RNLs revealed that all collapsed into NRG1-clade, rather than four. To investigate more in depth the means of intraspecific variability of grape RNL copies, a transcriptomic profiling in response to powdery mildew (PM) infection was carried out through qRT-PCRs and public databases interrogation. The RNL expression variability identified in transcriptome data sets supports the hypothesis of a functional expansion/contraction in grapevine varieties. Although no direct correlations between grapevine PM-resistance and RNL expression was identified, our work can provide good candidates for functional studies able to elucidate the putative “helper” role of RNLs in grape immune signalling.

中文翻译：

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推断种子植物中 RPW8-NLRs 的进化模式：Vitis vinifera 的案例研究

主要结论植物的基因组学和转录组学研究，更深入的葡萄藤研究表明，抗病 RNL 基因家族是高度可变的。 NLRs) 在植物中鉴定。两个 RNL，即 NRG1（N 需求基因 1）和 ADR1（激活的抗病性 1）已被表征；然而，对高等植物中RNL的进化历史知之甚少。为了追踪 RNL 基因亚科的多样化，我们扫描了属于 29 个分类群的 73 个植物基因组的 NLR 蛋白，揭示了物种间和同一属或植物科内的显着多样化以及重要作物物种的显着扩张。为了探索 Vitis vinifera 的 RNL 变异性并获得有关其结构的信息，已将五个葡萄基因组（'Aglianico'、'Falanghina'、'Sultanina'、'Tannat'和'Nebbiolo'）的进化多样化与参考基因组（“黑比诺”）。与 10 个“黑比诺”RNL 相比，RNL 的数量从 6 个（'Sultanina'）到 14 个（'Nebbiolo'）不等。对葡萄树 RNL 的系统发育研究表明，所有这些都塌陷为 NRG1 进化枝，而不是四个。为了更深入地研究葡萄 RNL 拷贝的种内变异性方法，通过 qRT-PCR 和公共数据库查询进行了对白粉病 (PM) 感染的转录组分析。在转录组数据集中确定的 RNL 表达变异性支持葡萄品种功能扩张/收缩的假设。虽然没有发现葡萄树 PM 抗性和 RNL 表达之间的直接相关性，但我们的工作可以为功能研究提供很好的候选者，以阐明 RNL 在葡萄免疫信号传导中的推定“帮助”作用。