Multiple emergences of genetically diverse amphibian-infecting chytrids include a globalized hypervirulent recombinant lineage
Multiple emergences of genetically diverse amphibian-infecting chytrids include a globalized hypervirulent recombinant lineage
复制标题
DOI：
10.1073/pnas.1111915108
复制
发表时间：
2011-11-15
影响因子：
11.1
通讯作者：
Fisher, Matthew C.
中科院分区：
文献类型：
--
作者：
Farrer, Rhys A.;Weinert, Lucy A.;Fisher, Matthew C.
水蛭壶菌（Batrachochytrium dendroatidis, Bd）是一种全球普遍存在的真菌感染，已成为两栖动物生物多样性丧失的主要驱动因素。尽管广泛努力了解这种流行性传染病的出现，但感染的起源、全球传播的模式和主要的进化模式在很大程度上仍然未知。使用比较种群基因组学，我们发现了与两栖动物相关的三个深度分化的Bd谱系。其中两种谱系分布在多个大陆，与两栖动物贸易引入的已知物种有关。我们发现，在20世纪，至少在五大洲出现了属于一个分支的分离株，即全球流行性传染病谱系（BdGPL），并与北美、中美洲、加勒比海、澳大利亚和欧洲的动物流行病的发病有关。两个新发现的分化谱系，Cape谱系（BdCAPE）和Swiss谱系（BdCH），在与BdGPL和BdGPL进行比较时发现形态特征不同，并且我们表明BdGPL是高毒力的。BdGPL独特地具有基因组重组的特征，表现为广泛的基因组间系统发育冲突和斑驳分布的杂合性。我们推测，以前遗传上隔离的异源种群之间的接触可能允许发生重组，导致高毒性BdGPL的产生、传播和入侵，导致当代疾病驱动的两栖动物生物多样性损失。
Batrachochytrium dendrobatidis (Bd) is a globally ubiquitous fungal infection that has emerged to become a primary driver of amphibian biodiversity loss. Despite widespread effort to understand the emergence of this panzootic, the origins of the infection, its patterns of global spread, and principle mode of evolution remain largely unknown. Using comparative population genomics, we discovered three deeply diverged lineages of Bd associated with amphibians. Two of these lineages were found in multiple continents and are associated with known introductions by the amphibian trade. We found that isolates belonging to one clade, the global panzootic lineage (BdGPL) have emerged across at least five continents during the 20th century and are associated with the onset of epizootics in North America, Central America, the Caribbean, Australia, and Europe. The two newly identified divergent lineages, Cape lineage (BdCAPE) and Swiss lineage (BdCH), were found to differ in morphological traits when compared against one another and BdGPL, and we show that BdGPL is hypervirulent. BdGPL uniquely bears the hallmarks of genomic recombination, manifested as extensive intergenomic phylogenetic conflict and patchily distributed heterozygosity. We postulate that contact between previously genetically isolated allopatric populations of Bd may have allowed recombination to occur, resulting in the generation, spread, and invasion of the hypervirulent BdGPL leading to contemporary disease-driven losses in amphibian biodiversity.