Analysis of rbcL sequences reveals the global biodiversity, community structure, and biogeographical pattern of thermoacidophilic red algae (Cyanidiales)

Abstract

Thermoacidophilic cyanidia (Cyanidiales) are the primary photosynthetic eukaryotes in volcanic areas. These red algae also serve as important model organisms for studying life in extreme habitats. The global biodiversity and community structure of Cyanidiales remain unclear despite previous sampling efforts. Here, we surveyed the Cyanidiales biodiversity in the Tatun Volcano Group (TVG) area in Taiwan using environmental DNA sequencing. We generated 174 rbcL sequences from eight samples from four regions in the TVG area, and combined them with 239 publicly available rbcL sequences collected worldwide. Species delimita-tion using this large rbcL data set suggested at least 20 Cyanidiales OTUs (operational taxono-mic units) worldwide, almost three times the presently recognized seven species. Results from environmental DNA showed that OTUs in the TVG area were divided into three groups: (i) dominant in hot springs with 92%-99% sequence identity to Galdieria maxima; (ii) largely distributed in drier and more acidic microhabitats with 99% identity to G. partita; and (iii) primarily distributed in cooler microhabitats and lacking identity to known cyanidia species (a novel Cyanidiales lineage). In both global and individual area analyses, we observed greater species diversity in non-aquatic than aquatic habitats. Community structure analysis showed high similarity between the TVG community and West Pacific-Iceland communities, reflecting their geographic proximity to each other. Our study is the first examination of the global species diversity and biogeographic affinity of cyanidia. Additionally, our data illuminate the influence of microhabitat type on Cyanidiales diversity and highlight intriguing questions for future ecological research.

Burning coal spoil heaps as a new habitat for the extremophilic red alga Galdieria sulphuraria

“…Compared to its counterparts from Cyanidiales, Galdieria is the most flexible and adaptable one (reviewed in YooN et al 2006) and could be the most sucessful to establish and sustain its populations where its survival requirements are provided. In addition to that, our study supports a biogeographical pattern of G. sulphuraria (TopliN et al 2008;CiNiglia et al 2014;Hsieh et al 2015). Moreover, here we demonstrate that it is highly likely that the Italian populations of Galdieria could be the potential source of this extremophile within all central Europe if only suitable habitats for this alga were established.…”

“…For example, it is well known from Italy (Gross et al 1998;CiNiglia et al 2004;YooN et al 2006;PiNto et al 2007), Yellowstone National Park, USA (Ferris et al 2005;Skorupa et al 2013), New Zealand (TopliN et al 2008 and Iceland (CiNiglia et al 2014). Rocks and sediments surrounding hot sulphur springs, steaming fumaroles or boiling mud pools are typical habitats for this extremophile (Gross et al 1998;CiNiglia et al 2004CiNiglia et al , 2014Ferris et al 2005;YooN et al 2006;PiNto et al 2007;TopliN et al 2008;Skorupa et al 2013;Hsieh et al 2015). Although Galdieria is found all over the world, its distibution is discontinuous due to special growth and habitat requirements.…”

Corrigendum

“…This error, however, does not affect the reported results in Hsieh et al. (). We apologize for this error.…”

“…It was brought to our attention that the published Figures 1, S2, and S4, and Table S2 in Hsieh et al. () contain an error. Italy (10D; AB002583) was mislabeled as YNP, USA (10D; AB002583).…”

The effects of contemporary selection and dispersal limitation on the community assembly of acidophilic microalgae

“…, Hsieh et al. ). The studies published to date used low‐resolution genetic markers such as 18S ribosomal RNA (e.g., Gross et al.…”