Obase Keisuke, Matsuda Yosuke
Department of Plant Pathology, University of Florida, 2523 Fifield Hall, Gainesville, FL, 32611-0680, USA,
Mycorrhiza. 2014 Nov;24(8):635-44. doi: 10.1007/s00572-014-0584-5. Epub 2014 May 3.
Roots of plants in the genus Enkianthus, which belongs to the earliest diverging lineage in the Ericaceae, are commonly colonized by arbuscular mycorrhizal (AM) fungi. We documented the community of fungal root endophytes associated with Enkianthus species using a culture-based method for better understanding the members of root-colonizing fungi, except for AM fungi. Fungal isolates were successfully obtained from 610 out of 3,599 (16.9 %) root segments. Molecular analysis of fungal cultures based on ribosomal internal transcribed spacer (ITS) sequences yielded 63 operational taxonomical units (OTUs: 97 % sequence similarity cutoff) from 315 representative isolates. Further phylogenetic analysis showed that most (296 isolates) belonged to Ascomycota and were either members of Helotiales (Dermataceae, Hyaloscyphaceae, Phialocephala and Rhizoscyphus ericae aggregate), Oidiodendron, or other Pezizomycotina. Twenty-three out of 63 OTUs, which mainly consisted of Leotiomycetes, showed high similarities with reference sequences derived from roots of other ericaceous plants such as Rhododendron. The results indicated that Enkianthus houses variable root mycobionts including putative endophytic and mycorrhizal fungi in addition to AM fungi.
吊钟花属植物属于杜鹃花科中最早分化出来的谱系，其根系通常被丛枝菌根（AM）真菌定殖。我们使用基于培养的方法记录了与吊钟花属物种相关的真菌根内生菌群落，以便更好地了解除AM真菌外的根系定殖真菌成员。从3599个根段中的610个（16.9%）成功获得了真菌分离株。基于核糖体内部转录间隔区（ITS）序列对真菌培养物进行分子分析，从315个代表性分离株中得到了63个操作分类单元（OTU：序列相似性阈值为97%）。进一步的系统发育分析表明，大多数（296个分离株）属于子囊菌门，是柔膜菌目（皮盘菌科、透明盘菌科、瓶梗孢属和欧石楠类根生菌复合体）、粉孢革菌属或其他粪壳菌纲的成员。63个OTU中有23个主要由散囊菌纲组成，与从其他杜鹃花科植物（如杜鹃属）的根中获得的参考序列具有高度相似性。结果表明，除AM真菌外，吊钟花属还存在多种根菌共生体，包括假定的内生真菌和菌根真菌。
