Genotypic and phenotypic characterization of the European A2 isolates of Phytophthora ramorum
Genotypic and phenotypic characterization of the European A2 isolates of Phytophthora ramorum
复制标题
欧洲 A2 疫霉菌分离株的基因型和表型特征
DOI：
--
复制
发表时间：
2011
影响因子：
1.8
通讯作者：
K. Heungens
中科院分区：
文献类型：
--
作者：
A. Vercauteren;I. Dobbelaere;E. Bockstaele;M. Maes;K. Heungens
雷莫鲁姆疫霉（Phytophthora ramorum）是一种最近描述的北美和欧洲病原体，具有三个克隆谱系。 NA1和NA2谱系存在于北美森林和苗圃中，而EU1谱系主要出现在欧洲苗圃中。 P. ramorum 是异宗合的，有两种交配类型 A1 和 A2。所有 NA1 和 NA2 分离株均为 A2 交配型。首次收集时，所有 EU1 分离株均为 A1 交配型，但 2002 年在比利时收集的一个 A2 分离株除外。对 410 个其他比利时分离株的交配型进行筛选，发现另外两个 EU1-A2 分离株于 2002 年和 2003 年收集。PCR-RFLP、AFLP 和 SSR 标记用于确定交配型变化的性质。这三个分离株没有表现出有性重组或有丝分裂交叉的迹象，表明突变或有丝分裂基因转换是交配类型变化最可能的解释。我们将 EU1-A2 分离株与 EU1-A1 和 NA1-A2 分离株在四种寄主植物上的致病性和孢子形成特征进行了比较。尽管对某些宿主的致病性差异较小，但 EU1-A2 分离株对彼此以及对 EU1-A1 分离株具有相似的攻击性，并且比 NA1-A2 分离株更具攻击性。 EU1-A2 分离株之间以及 EU1-A1 和 EU1-A2 分离株之间的孢子形成特征也具有可比性，但 EU1-A2 分离株 BBA 26/02 除外。 EU1-A2 分离株之间有限的基因型和表型差异可能是在交配类型改变后进化的，这可能在分离株被发现之前几年就发生了。有强烈迹象表明 EU1-A2 种群已从比利时消灭。
Phytophthora ramorum, a recently described North American and European pathogen, has three clonal lineages. The NA1 and NA2 lineages are found in North American forests and nurseries, while the EU1 lineage appears mainly in European nurseries. P. ramorum is heterothallic, having two mating types A1 and A2. All NA1 and NA2 isolates are of A2 mating type. When first collected, all EU1 isolates were of A1 mating type, with the exception of one A2 isolate collected in Belgium in 2002. Screening 410 other Belgian isolates for mating type revealed two additional EU1-A2 isolates collected in 2002 and 2003. PCR-RFLP, AFLP and SSR markers were used to determine the nature of the mating type change. The three isolates show no indications of sexual recombination or mitotic crossing over, indicating that mutation or mitotic gene conversion is the most likely explanation for the mating type change. We compared the pathogenicity and sporulation characteristics of the EU1-A2 isolates to those of EU1-A1 and NA1-A2 isolates on four host plants. Despite small differences in pathogenicity on some hosts, the EU1-A2 isolates were similarly aggressive to each other and to the EU1-A1 isolates and more aggressive than the NA1-A2 isolates. Sporulation characteristics were also comparable among EU1-A2 isolates and between EU1-A1 and EU1-A2 isolates, except for EU1-A2 isolate BBA 26/02. The limited genotypic and phenotypic differences between EU1-A2 isolates probably evolved after the mating type change, which may have occurred several years before the isolates were detected. There are strong indications that the EU1-A2 population has been eradicated from Belgium.