Phylogenetic status and pathogenicity of Metarhizium majus isolated from a fruit beetle larva in Japan
Phylogenetic status and pathogenicity of Metarhizium majus isolated from a fruit beetle larva in Japan
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DOI：
10.1007/s11557-015-1082-7
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发表时间：
2015-08-01
影响因子：
2.4
通讯作者：
Shimizu, Susumu
中科院分区：
文献类型：
--
作者：
Nishi, Oumi;Iiyama, Kazuhiro;Shimizu, Susumu
一些带有大分生孢子的绿僵菌（Metarhizium anisopliae sensu lato）分离物（MALC），以前称为绿僵菌变种（M. anisopliae var. var.）。 majus 来自金龟子宿主，例如椰子犀牛甲虫 (Oryctes spp.) 的分离株，其宿主范围较窄，并且特别适应其原始宿主。尽管最近根据 DNA 序列对绿僵菌属进行了分类学修订，但 MALC 宿主偏好的变化尚未与 DNA 序列变化联系起来。本研究重点研究从日本果甲虫幼虫 Protaetia orientalis submarumorea (Pos) 中分离的 MALC 的系统发育状况和致病性，以探讨 MALC 毒力与核苷酸序列变异之间的关系。根据对五个位点 DNA 序列的系统发育分析结果，我们从 Pos (Hn1) 中鉴定出一个分离株为 M. majus，它由许多来自金龟子昆虫的带有大分生孢子的分离株组成。在对遗传多样性绿僵菌分离株的毒力测定中，只有 Hn1 及其最密切相关的土壤分离株对 Pos 表现出致病性；然而，这些阳性致病菌株对家蚕的毒力较弱。在对 rDNA 基因间间隔区的分析中，Pos 致病分离株表现出独特的序列变异，并与密切相关的谱系明显区分开来，包括来自 Oryctes sp. 的分离株，后者形成了一个单独的单系群。这些结果表明，来自日本的 Pos 致病性分离株特别适应 Pos，并且可以在遗传上与来自不同金龟子昆虫的 M. majus 分离株进行区分。
Some isolates of Metarhizium anisopliae sensu lato with large conidia (MALC), which was formerly known as M. anisopliae var. majus, from a scarabaeid host, such as isolates from the coconut rhinoceros beetle (Oryctes spp.), have a narrow host range and are particularly adapted to their original host. Despite recent taxonomic revisions of the genus Metarhizium on the basis of DNA sequences, variations in host preferences of MALC have not been linked to DNA sequence variations. This study focused on the phylogenetic status and pathogenicity of MALC isolated from the fruit beetle larva Protaetia orientalis submarumorea (Pos) in Japan to investigate the relationship between virulence and nucleotide sequence variation among MALC. On the basis of the results of the phylogenetic analyses of DNA sequences from five loci, we identified an isolate from Pos (Hn1) as M. majus, which comprised many isolates with large conidia from scarabaeid insects. In the virulence assay of genetically diverse Metarhizium isolates, only Hn1 and its most closely related isolates from soil showed pathogenicity to Pos; however, these Pos-pathogenic isolates showed weak virulence against silkworms. In the analysis of the intergenic spacer region of rDNA, the Pos-pathogenic isolates displayed unique sequence variation and were clearly distinguished from closely related lineages, including isolates from Oryctes sp., which formed a separate monophyletic group. These results indicate that the Pos-pathogenic isolates from Japan are particularly adapted to Pos and can be genetically distinguished from M. majus isolates from different scarabaeid insects.