Phylogenetic relationships, host affinity, and geographic structure of boreal and arctic endophytes from three major plant lineages
Phylogenetic relationships, host affinity, and geographic structure of boreal and arctic endophytes from three major plant lineages
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DOI：
10.1016/j.ympev.2006.07.012
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发表时间：
2007-02-01
影响因子：
4.1
通讯作者：
Lutzoni, Francois
中科院分区：
文献类型：
--
作者：
Higgins, K. Lindsay;Arnold, A. Elizabeth;Lutzoni, Francois
虽然与所有植物相关，但真菌内生菌(生活在健康植物组织中的微真菌)在真菌多样性中所占比例尚不清楚。虽然越来越多的人认识到它们的生态重要性和人类用途，但对它们的宿主专一性、地理结构或系统发育关系知之甚少。我们调查了北部和南部北方森林(加拿大魁北克)和北极冻原(加拿大努纳武特)三种植物(石杉、云杉和仙人掌，分别代表番茄、针叶和被子植物)的健康光合作用组织中的内生子囊菌。从调查的所有植物物种中回收内生菌，并在每个寄主物种检查的2 mm(2)组织片段中存在1-4%的内生菌。获得了558株分离物中280株的核糖体内转录间隔区(ITS)的序列数据。基于其基因类型的物种积累曲线仍然是非渐近的，Bootstrap分析表明，仍有大量的基因类型有待发现。大多数基因型仅从单一寄主物种中恢复，只有6%的基因型在北方群落和北极群落之间共享。来自核大小核糖体亚基(LSUrDNA，SSUrDNA；2.4kb)的两个独立的贝叶斯分析和相邻连接的Bootstrap分析表明，北方和北极的内生菌代表丝状真菌、丝状菌目、毛霉科、平菇和甲菌。许多得到良好支持的系统类型只包含内生菌，尽管对子囊菌门的可用序列进行了详尽的采样。总之，这些数据表明高纬度地区内生菌的多样性比预期的要大，并为评估这些鲜为人知但普遍存在的活植物共生体的进化提供了一个框架。(C)2006 Elsevier Inc.保留所有权利。
Although associated with all plants, fungal endophytes (microfungi that live within healthy plant tissues) represent an unknown proportion of fungal diversity. While there is a growing appreciation of their ecological importance and human uses, little is known about their host specificity, geographic structure, or phylogenetic relationships. We surveyed endophytic Ascomycota from healthy photosynthetic tissues of three plant species (Huperzia selago, Picea mariana, and Dryas integrifolia, representing lycophytes, conifers, and angiosperms, respectively) in northern and southern boreal forest (Quebec, Canada) and arctic tundra (Nunavut, Canada). Endophytes were recovered from all plant species surveyed, and were present in < 1-4% of 2 mm(2) tissue segments examined per host species. Sequence data from the nuclear ribosomal internal transcribed spacer region (ITS) were obtained for 280 of 558 isolates. Species-accumulation curves based on ITS genotypes remained non-asymptotic, and bootstrap analyses indicated that a large number of genotypes remain to be found. The majority of genotypes were recovered from only a single host species, and only 6% of genotypes were shared between boreal and arctic communities. Two independent Bayesian analyses and a neighbor-joining bootstrapping analysis of combined data from the nuclear large and small ribosomal subunits (LSUrDNA, SSUrDNA; 2.4 kb) showed that boreal and arctic endophytes represent Dothideomycetes, Sordariomycetes, Chaetothyriomycetidae, Leotiomycetes, and Pezizomycetes. Many well-supported phylotypes contained only endophytes despite exhaustive sampling of available sequences of Ascomycota. Together, these data demonstrate greater than expected diversity of endophytes at high-latitude sites and provide a framework for assessing the evolution of these poorly known but ubiquitous symbionts of living plants. (c) 2006 Elsevier Inc. All rights reserved.