Stable isotope analyses reveal previously unknown trophic mode diversity in the Hymenochaetales
Stable isotope analyses reveal previously unknown trophic mode diversity in the Hymenochaetales
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DOI：
10.1002/ajb2.1183
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发表时间：
2018-11-01
影响因子：
3
通讯作者：
Matheny, P. Brandon
中科院分区：
文献类型：
--
作者：
Korotkin, Hailee B.;Swenie, Rachel A.;Matheny, P. Brandon
研究方法的前提是膜毛目真菌主要是参与木材腐烂的木质腐生真菌。然而，该类群还包括苔藓和陆生类群，但它们的营养模式尚不清楚。在这里，我们研究了许多非木质化膜毛目动物的碳和氮利用模式，并提供了这些非典范生态行会产生的系统发育背景。我们结合三角洲C-13和三角洲N-15的稳定同位素分析和系统发育分析来探讨营养模式的分配和演化。进行了聚类程序和统计测试，以指定膜毛目动物的营养模式，并测试不同生态系统之间的差异。对膜毛菌目的基因组进行了挖掘，以寻找与植物细胞壁、木质素降解和蔗糖裂解活性有关的酶的存在。主要结果结论共检测到3个不同的营养类群：生物营养类、腐生营养类，第二类营养类群包括大量的苔藓类膜毛纲和苔藓类。非木质化的膜毛目动物一般具有生物营养性。所有木质膜毛类均为腐生型，大多数三色膜毛类为外生菌根。总体而言，至少有15种膜毛目动物被推断为具有生物营养。嗜绿立克次体能够降解植物细胞壁和木质素，并将蔗糖分解为葡萄糖，这与寄生或内生的生活方式一致。大多数非木质化的膜毛目动物是生物营养型的。许多嗜苔藓的膜毛纲的稳定同位素值以外生菌根的形式聚集，或以指示寄生或内生生活方式的生物营养簇的形式聚集。总体而言，膜毛目动物的营养模式多样性比预期的要大，非木质生态特征和生物营养模式是进化衍生的特征。
Premise of the Study Methods The Hymenochaetales are dominated by lignicolous saprotrophic fungi involved in wood decay. However, the group also includes bryophilous and terricolous taxa, but their modes of nutrition are not clear. Here, we investigate patterns of carbon and nitrogen utilization in numerous non-lignicolous Hymenochaetales and provide a phylogenetic context in which these non-canonical ecological guilds arose. We combined stable isotope analyses of delta C-13 and delta N-15 and phylogenetic analyses to explore assignment and evolution of nutritional modes. Clustering procedures and statistical tests were performed to assign trophic modes to Hymenochaetales and test for differences between varying ecologies. Genomes of Hymenochaetales were mined for presence of enzymes involved in plant cell wall and lignin degradation and sucrolytic activity. Key Results Conclusions Three different trophic clusters were detected - biotrophic, saprotrophic, and a second biotrophic cluster including many bryophilous Hymenochaetales and mosses. Non-lignicolous Hymenochaetales are generally biotrophic. All lignicolous Hymenochaetales clustered as saprotrophic and most terricolous Hymenochaetales clustered as ectomycorrhizal. Overall, at least 15 species of Hymenochaetales are inferred as biotrophic. Bryophilous species of Rickenella can degrade plant cell walls and lignin, and cleave sucrose to glucose consistent with a parasitic or endophytic life style. Most non-lignicolous Hymenochaetales are biotrophic. Stable isotope values of many bryophilous Hymenochaetales cluster as ectomycorrhizal or in a biotrophic cluster indicative of parasitism or an endophytic life style. Overall, trophic mode diversity in the Hymenochaetales is greater than anticipated, and non-lignicolous ecological traits and biotrophic modes of nutrition are evolutionarily derived features.