Identification of pathogenicity-related genes in Fusarium oxysporum f. sp. cepae.
Identification of pathogenicity-related genes in Fusarium oxysporum f. sp. cepae.
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DOI：
10.1111/mpp.12346
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发表时间：
2016-09
影响因子：
4.9
通讯作者：
Clarkson JP
中科院分区：
文献类型：
--
作者：
Taylor A;Vágány V;Jackson AC;Harrison RJ;Rainoni A;Clarkson JP
尖孢镰刀菌（Fusarium oxysporum）的病原分离物，被区分为特殊形式（formae speciales（f.种属）根据其寄主特异性，在世界范围内引起许多重要作物的冠腐、根腐病和维管萎蔫。香蕉枯萎洋葱疫霉（FOC）对全世界的洋葱种植者来说是特别成问题的，并且在英国的流行率正在增加。我们对31 F.使用致病性测试、管家基因测序和效应物鉴定从英国洋葱收集的尖孢菌分离物。在洋葱幼苗和鳞茎试验中，21个菌株致病，10个是非致病的。这些分离物的分子特征，以及21个额外的分离物，包括其他f。spp.和不同镰刀菌属物种，通过测序三个管家基因进行。一个连接的树将F.尖孢菌分离株分为六个分支，但没有区分致病性和非致病性分离株。在FOC中鉴定了10个推定的效应子，包括7个首次在F. oxysporum F.番茄叶锈菌还鉴定了两个具有信号肽和RxLR基序的高度同源蛋白质（CRX 1/CRX 2）和一个没有先前表征的结构域的基因（C5）。这些基因中有9个的存在/不存在与对洋葱的致病性密切相关，并且所有这些基因都被证明在植物中表达。不同的SIX基因互补序列在其他f。spp.，但在洋葱的其他三种镰刀菌中没有鉴定出。虽然FOC-SIX基因与其它F.S. spp.，FOC特有的序列存在明显差异，而CRX 1和C5基因似乎主要是FOC特异性的。
Pathogenic isolates of Fusarium oxysporum, distinguished as formae speciales (f. spp.) on the basis of their host specificity, cause crown rots, root rots and vascular wilts on many important crops worldwide. Fusarium oxysporum f. sp. cepae (FOC) is particularly problematic to onion growers worldwide and is increasing in prevalence in the UK. We characterized 31 F. oxysporum isolates collected from UK onions using pathogenicity tests, sequencing of housekeeping genes and identification of effectors. In onion seedling and bulb tests, 21 isolates were pathogenic and 10 were non‐pathogenic. The molecular characterization of these isolates, and 21 additional isolates comprising other f. spp. and different Fusarium species, was carried out by sequencing three housekeeping genes. A concatenated tree separated the F. oxysporum isolates into six clades, but did not distinguish between pathogenic and non‐pathogenic isolates. Ten putative effectors were identified within FOC, including seven Secreted In Xylem (SIX) genes first reported in F. oxysporum f. sp. lycopersici. Two highly homologous proteins with signal peptides and RxLR motifs (CRX1/CRX2) and a gene with no previously characterized domains (C5) were also identified. The presence/absence of nine of these genes was strongly related to pathogenicity against onion and all were shown to be expressed in planta. Different SIX gene complements were identified in other f. spp., but none were identified in three other Fusarium species from onion. Although the FOC SIX genes had a high level of homology with other f. spp., there were clear differences in sequences which were unique to FOC, whereas CRX1 and C5 genes appear to be largely FOC specific.