Functional, Phylogenetic and Host-Geographic Signatures of Labyrinthula spp. Provide for Putative Species Delimitation and a Global-Scale View of Seagrass Wasting Disease

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• 作者：Daniel L. Martin ; Ylenia Chiari ; Emily Boone ; Timothy D. Sherman…
• 刊名：Estuaries and Coasts
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：39
• 期：5
• 页码：1403-1421
• 全文大小：1,712 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Environment
  Environment
  Ecology
  Geosciences
  Environmental Management
  Nature Conservation
  
• 出版者：Springer New York
• ISSN：1559-2731
• 卷排序：39

文摘

Seagrass meadows form ecologically and economically valuable coastal habitat on every continental margin except the Antarctic, but their areal extent is declining by approximately 2–5 % per year. Seagrass wasting disease is a contributing factor in these declines, with the protist Labyrinthula identified as the etiologic agent. To help elucidate the role of Labyrinthula spp. in global seagrass declines, we surveyed roughly one fourth of all seagrass species to identify Labyrinthula diversity at the strain and/or species level, combining results from culturing methods and two common nuclear DNA markers: the ITS and 18S regions of the ribosomal RNA gene complex. After assaying a subset of the resulting isolates (of which 170 were newly sequenced), we produced a cladogenic context for putative seagrass-pathogenic versus non-pathogenic Labyrinthula while also defining host and geographic ranges. Assays also suggest that pathogenicity is consistently high (when present; and, even when comparing susceptibility of US East- versus West Coast Zostera marina hosts) while virulence is variable, that some isolate-host combinations have the potential for host cross-infection, and that several modes of transmission can be effective. Taken together, these data provide additional means for delimiting putative species of Labyrinthula, suggesting at least five seagrass-pathogenic and perhaps ten or more non-pathogenic marine “species”, yielding a working definition for ecologists and epidemiologists attempting to reconcile the sundry data related to seagrass wasting disease.Keywords18SSSUITSrDNABiogeographyEmerging infectious diseasesOpportunistParasitePhylogeographyPlant-pathogen interactionsVirulenceLabyrinthula zosteraeThalassia testudinumZostera marina