Bruzone M Clara, Fehrer Judith, Fontenla Sonia B, Vohník Martin
Laboratorio de Microbiología Aplicada y Biotecnología, Centro Regional Universitario Bariloche, INIBIOMA (Universidad Nacional del Comahue-CONICET), Bariloche, Río Negro, Argentina.
DNA Laboratory, Institute of Botany, Czech Academy of Sciences (CAS), Průhonice, CZ-252 43, Czech Republic.
Mycorrhiza. 2017 Feb;27(2):147-163. doi: 10.1007/s00572-016-0738-8. Epub 2016 Oct 25.
Ericoid mycorrhiza is arguably the least investigated mycorrhizal type, particularly when related to the number of potential hosts and the ecosystems they inhabit. Little is known about the global distribution of ericoid mycorrhizal (ErM) fungi, and this holds true even for the prominent ErM mycobiont Rhizoscyphus ericae. Earlier studies suggested R. ericae might be low in abundance or absent in the roots of Southern Hemisphere's Ericaceae, and our previous investigations in two Argentine Patagonian forests supported this view. Here, we revisited the formerly investigated area, albeit at a higher altitude, and screened fungi inhabiting hair roots of Gaultheria caespitosa and Gaultheria pumila at a treeless alpine site using the same methods as previously. We obtained 234 isolates, most of them belonging to Ascomycota. In contrast to previous findings, however, among 37 detected operational taxonomic units (OTUs), OTU 1 (=R. ericae s. str.) comprised the highest number of isolates (87, ∼37 %). Most of the OTUs and isolates belonged to the Helotiales, and 82.5 % of isolates belonged to OTUs shared between both Gaultheria species. At the alpine site, ericoid mycorrhizal fungi dominated, followed by dark septate endophytes and aquatic hyphomycetes probably acting as root endophytes. Our results suggest that the distribution of R. ericae is influenced, among others, by factors related to altitude such as soil type and presence/absence and type of the neighboring vegetation. Our study is the first report on R. ericae colonizing Ericaceae roots in the Southern Hemisphere and extends the known range of this prominent ErM species to NW Patagonia.
石楠类菌根可以说是研究最少的菌根类型，尤其是在涉及潜在宿主数量及其所栖息的生态系统方面。人们对石楠类菌根（ErM）真菌的全球分布知之甚少，即使是著名的ErM真菌共生体埃里卡根生壳囊孢（Rhizoscyphus ericae）也是如此。早期研究表明，埃里卡根生壳囊孢在南半球石楠科植物的根系中可能数量稀少或不存在，我们之前在阿根廷巴塔哥尼亚的两片森林中的调查支持了这一观点。在此，我们重新考察了之前研究过的区域，尽管海拔更高，并采用与之前相同的方法，在一个无树的高山地带筛选了栖息于丛生白珠树（Gaultheria caespitosa）和矮小刺叶白珠（Gaultheria pumila）须根中的真菌。我们获得了234个分离株，其中大多数属于子囊菌门。然而，与之前的研究结果不同的是，在检测到的37个可操作分类单元（OTU）中，OTU 1（=狭义的埃里卡根生壳囊孢）包含的分离株数量最多（87个，约占37%）。大多数OTU和分离株属于柔膜菌目，82.5%的分离株属于两个白珠树物种共有的OTU。在高山地带，石楠类菌根真菌占主导地位，其次是深色有隔内生真菌和可能作为根内生真菌的水生丝孢菌。我们的结果表明，埃里卡根生壳囊孢的分布受到多种因素的影响，其中包括与海拔相关的因素，如土壤类型、邻近植被的有无及类型。我们的研究是关于埃里卡根生壳囊孢在南半球定殖于石楠科植物根系的首次报道，并将这种著名的ErM物种的已知分布范围扩展到了巴塔哥尼亚西北部。
