Comparative Genomics of Early-Diverging Mushroom-Forming Fungi Provides Insights into the Origins of Lignocellulose Decay Capabilities
Comparative Genomics of Early-Diverging Mushroom-Forming Fungi Provides Insights into the Origins of Lignocellulose Decay Capabilities
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DOI：
10.1093/molbev/msv337
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发表时间：
2016-04-01
影响因子：
10.7
通讯作者：
Hibbett, David S.
中科院分区：
文献类型：
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作者：
Nagy, Laszlo G.;Riley, Robert;Hibbett, David S.
木质纤维素分解的进化是真菌在生态学上最重要的创新之一。伞菌纲白腐菌是降解木本植物细胞壁中纤维素和木质素的最有效的微生物。然而，木质纤维素分解的确切进化起源知之甚少，主要是因为某些早期分歧分支的伞菌和它的姐妹群，Dacrymycetes，还没有被采样，或已采样不足，在比较基因组研究。在这里，我们提出了新的基因组序列的10腐营养真菌，包括成员的Dacrymycetes和早期分歧的分支伞菌（Cantharellales，Sebacinales，木耳目，Trechisporales），我们用它来完善的起源和进化历史的木质纤维素分解的酶工具包。我们重建了木质素分解酶的起源，重点是II类过氧化物酶（AA 2），以及攻击结晶纤维素的酶。尽管以前的报道白色腐烂出现早在Dacrymycetes，我们的研究结果表明，白腐真菌进化较晚的伞菌纲，与第一个II类过氧化物酶重建的祖先木耳目和残留的伞菌。我们采样的伞菌纲最古老的分支的样本都缺乏II类过氧化物酶，因此得出结论，使用的组合的近晶和衍生的PCW降解酶，早于白色腐烂的演变。
Evolution of lignocellulose decomposition was one of the most ecologically important innovations in fungi. White-rot fungi in the Agaricomycetes (mushrooms and relatives) are the most effective microorganisms in degrading both cellulose and lignin components of woody plant cell walls (PCW). However, the precise evolutionary origins of lignocellulose decomposition are poorly understood, largely because certain early-diverging clades of Agaricomycetes and its sister group, the Dacrymycetes, have yet to be sampled, or have been undersampled, in comparative genomic studies. Here, we present new genome sequences of ten saprotrophic fungi, including members of the Dacrymycetes and early-diverging clades of Agaricomycetes (Cantharellales, Sebacinales, Auriculariales, and Trechisporales), which we use to refine the origins and evolutionary history of the enzymatic toolkit of lignocellulose decomposition. We reconstructed the origin of ligninolytic enzymes, focusing on class II peroxidases (AA2), as well as enzymes that attack crystalline cellulose. Despite previous reports of white rot appearing as early as the Dacrymycetes, our results suggest that white-rot fungi evolved later in the Agaricomycetes, with the first class II peroxidases reconstructed in the ancestor of the Auriculariales and residual Agaricomycetes. The exemplars of the most ancient clades of Agaricomycetes that we sampled all lack class II peroxidases, and are thus concluded to use a combination of plesiomorphic and derived PCW degrading enzymes that predate the evolution of white rot.