Has Scots pine (Pinus sylvestris) co-evolved with Dothistroma septosporum in Scotland? Evidence for spatial heterogeneity in the susceptibility of native provenances.
Has Scots pine (Pinus sylvestris) co-evolved with Dothistroma septosporum in Scotland? Evidence for spatial heterogeneity in the susceptibility of native provenances.
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DOI：
10.1111/eva.12395
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发表时间：
2016-09
影响因子：
4.1
通讯作者：
Ennos RA
中科院分区：
文献类型：
--
作者：
Perry A;Brown AV;Cavers S;Cottrell JE;Ennos RA
病原体压力的空间异质性导致宿主群体中疾病相关性状的遗传变异和进化。与此相反，宿主预计对外来病原体高度敏感，因为没有进化出防御反应。因此，宿主对病原体的反应可能是一种新的或地方性的病理系统的指标。目前，对原生英国苏格兰松（Pinus sylvestris）森林的最大威胁是由叶病原体隔孢多囊壳（Dothistroma septosporum）引起的多囊壳针叶枯萎病（DNB），据推测该病原体是外来的。2013年4月，将6年生苏格兰松的子代种源试验（包括8个原生种源，每个种源在6个区块中有4个家系）转移到加洛韦（Galloway）邻近DNB感染森林的一个砍伐地。在2年内（2013-2014年和2014-2015年;每年两次评估），目视评估了对隔孢梭菌的敏感性，测量为DNB严重程度（估计的当年非绿色针头百分比）。各年度感病性在种源间差异极显著，但家系间差异不显著。种源对隔孢梭菌的平均易感性与原产地的水相关变量呈负相关且显著相关，可能是由于宿主对高历史病原体压力的低易感性演变所致。
Spatial heterogeneity in pathogen pressure leads to genetic variation in, and evolution of, disease‐related traits among host populations. In contrast, hosts are expected to be highly susceptible to exotic pathogens as there has been no evolution of defence responses. Host response to pathogens can therefore be an indicator of a novel or endemic pathosystem. Currently, the most significant threat to native British Scots pine (Pinus sylvestris) forests is Dothistroma needle blight (DNB) caused by the foliar pathogen Dothistroma septosporum which is presumed to be exotic. A progeny–provenance trial of 6‐year‐old Scots pine, comprising eight native provenances each with four families in six blocks, was translocated in April 2013 to a clear‐fell site in Galloway adjacent to a DNB‐infected forest. Susceptibility to D. septosporum, measured as DNB severity (estimated percentage nongreen current‐year needles), was assessed visually over 2 years (2013–2014 and 2014–2015; two assessments per year). There were highly significant differences in susceptibility among provenances but not among families for each annual assessment. Provenance mean susceptibility to D. septosporum was negatively and significantly associated with water‐related variables at site of origin, potentially due to the evolution of low susceptibility in the host in response to high historical pathogen pressure.