In the last decade, the soil borne fungal pathogen Verticillium dahliae has had an increasingly strong effect on fiber flax (Linum usitatissimum L.), thus causing important yield losses in Normandy, France. Race-specific resistance against V. dahliae race 1 is determined by tomato Ve1, a leucine-rich repeat (LRR) receptor-like protein (RLP). Furthermore, homologous proteins have been found in various plant families. Herein, four homologs of tomato Ve1 were identified in the flax proteome database. The selected proteins were named LuVe11, LuVe12, LuVe13 and LuVe14 and were compared to other Ve1. Sequence alignments and phylogenic analysis were conducted and detected a high similarity in the content of amino acids and that of the Verticillium spp. race 1 resistance protein cluster. Annotations on the primary structure of these homologs reveal several features of tomato Ve1, including numerous copies of a 28 amino acids consensus motif [XXIXNLXXLXXLXLSXNXLSGXIP] in the LRR domain. An in vivo assay was performed using V. dahliae race 1 on susceptible and tolerant fiber flax cultivars. Despite the presence of homologous genes and the stronger expression of LuVe11 compared to controls, both cultivars exhibited symptoms and the pathogen was observed within the stem. Amino acid substitutions within the segments of the LRR domain could likely affect the ligand binding and thus the race-specific resistance. The results of this study indicate that complex approaches including pathogenicity tests, microscopic observations and gene expression should be implemented for assessing race-specific resistance mediated by Ve1 within the large collection of flax genotypes.

中文翻译：

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亚麻中番茄Ve1同源蛋白的鉴定和两种纤维亚麻品种对黄萎病种的抗特定种族的评估

在过去的十年中，土壤传播的真菌病原体大黄萎病菌对纤维亚麻（Linum usitatissimum L.）的作用日益增强，从而在法国诺曼底造成了重要的产量损失。对番茄大丽花种族1的种族特异性抗性由番茄Ve1（一种富含亮氨酸的重复序列（LRR）受体样蛋白（RLP））确定。此外，已经在各种植物科中发现了同源蛋白。在此，在亚麻蛋白质组数据库中鉴定出番茄Ve1的四个同源物。所选蛋白分别命名为LuVe11，LuVe12，LuVe13和LuVe14，并与其他Ve1进行了比较。进行了序列比对和系统发育分析，并检测到氨基酸和黄萎病菌的含量高度相似spp。种族1抗性蛋白簇。这些同源物的一级结构的注释揭示了番茄Ve1的几个特征，包括LRR域中28个氨基酸的共有基序[XXIXNLXXLXXLXLLXLSXNXLSGXIP]的多个副本。使用V. dahliae种族1在易感和耐受的纤维亚麻品种上进行了体内分析。尽管存在同源基因且LuVe11的表达更强与对照相比，两个品种都表现出症状并且在茎中观察到病原体。LRR结构域的片段内的氨基酸取代可能会影响配体结合，从而影响种族特异性抗性。这项研究的结果表明，应采用复杂的方法（包括致病性测试，显微镜观察和基因表达）来评估大量亚麻基因型中由Ve1介导的种族特异性抗性。