Department of Plants, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, 48824, USA.
Reef Explorer, Votua Village, Nadroga, Fiji Islands.
Microb Ecol. 2019 Jul;78(1):136-146. doi: 10.1007/s00248-018-1266-1. Epub 2018 Oct 4.
The Fiji Islands is an archipelago of more than 330 islands located in the tropics of the South Pacific Ocean. Microbial diversity and biogeography in this region is still not understood. Here, we present the first molecular characterization of fungal, bacterial, and archaeal communities in soils from different habitats within the largest Fijian island, Viti Levu. Soil samples were collected from under native vegetation in maritime-, forest-, stream-, grassland-, and casuarina-dominated habitats, as well as from under the introduced agricultural crops sugarcane, cassava, pine, and mahogany. Soil microbial diversity was analyzed through MiSeq amplicon sequencing of 16S (for prokaryotes), ITS, LSU ribosomal DNA (for fungi). Prokaryotic communities were dominated by Proteobacteria (~ 25%), Acidobacteria (~ 19%), and Actinobacteria (~ 17%), and there were no indicator species associated with particular habitats. ITS and LSU were congruent in β-diversity patterns of fungi, and fungal communities were dominated by Ascomycota (~ 57-64%), followed by Basidiomycota (~ 20-23%) and Mucoromycota (~ 10%) according to ITS, or Chytridiomycota (~ 9%) according to LSU. Indicator species analysis of fungi found statistical associations of Cenococcum, Wilcoxina, and Rhizopogon to Pinus caribaea. We hypothesize these obligate biotrophic fungi were co-introduced with their host plant. Entoloma was statistically associated with grassland soils, and Fusarium and Lecythophora with soils under cassava. Observed richness varied from 65 (casuarina) to 404 OTUs (cassava) for fungi according to ITS region, and from 1268 (pine) to 2931 OTUs (cassava) for bacteria and archaea. A major finding of this research is that nearly 25% of the fungal OTUs are poorly classified, indicative of novel biodiversity in this region. This preliminary survey provides important baseline data on fungal, bacterial, and archaeal diversity and biogeography in the Fiji Islands.
斐济群岛是南太平洋热带地区 330 多个岛屿的群岛。该地区的微生物多样性和生物地理学仍未被了解。在这里，我们展示了对斐济最大岛屿维提岛不同生境土壤中的真菌、细菌和古菌群落的首次分子特征描述。从海洋、森林、溪流、草原和木麻黄主导的生境下的原生植被下，以及从引入的农业作物甘蔗、木薯、松树和桃花心木下采集了土壤样本。通过对 16S（用于原核生物）、ITS、LSU 核糖体 DNA（用于真菌）的 MiSeq 扩增子测序分析了土壤微生物多样性。原核生物群落主要由变形菌门（25%）、酸杆菌门（19%）和放线菌门（17%）主导，没有与特定生境相关的指示物种。ITS 和 LSU 在真菌的β多样性模式上是一致的，真菌群落主要由子囊菌门（57-64%）主导，其次是担子菌门（20-23%）和毛霉门（10%）根据 ITS，或壶菌门（~9%）根据 LSU。真菌的指示种分析发现，Cenococcum、Wilcoxina 和 Rhizopogon 与加勒比松呈统计学关联。我们假设这些专性生物共生真菌是与它们的宿主植物共同引入的。Entoloma 与草原土壤呈统计学关联，而 Fusarium 和 Lecythophora 与木薯下的土壤呈统计学关联。根据 ITS 区，真菌的观察丰富度从 65（木麻黄）到 404 个 OTUs（木薯）不等，细菌和古菌的丰富度从 1268（松树）到 2931 OTUs（木薯）不等。这项研究的一个主要发现是，近 25%的真菌 OTUs 分类较差，表明该地区存在新的生物多样性。这项初步调查为斐济群岛的真菌、细菌和古菌多样性和生物地理学提供了重要的基线数据。
