| 内容提要: |
The heterotrophic labyrinthulomycete protists have long been known to play an important role in the nutrient cycling of coastal
seawater. Yet, their spatiotemporal abundance and diversity in polluted coastal waters remain poorly discussed, due in part to the
paucity of a rapid detection method. To this end, we developed a qPCR detection method based on a newly designed primer pair
targeting their 18S rRNA gene. Using this method, we studied the population dynamics of labyrinthulomycete protists in
nutrient-rich (Shenzhen Bay) and low-nutrient (Daya) coastal habitats along the Pearl River Delta. We found a significantly
(P <0.05) higher abundance of Labyrinthulomycetes in the Shenzhen bay (average 3455 gene copies mL −1 ) than that in Daya
Bay (average 378 gene copies mL −1 ). Their abundance gradient positively correlated (P <0.05) with the levels of inorganic
nitrogen and phosphates. Further characterization of the molecular diversity of these protists in Shenzhen Bay using different
primersetsrevealedthepresenceofseveralgenerabesidesa largenumberofunclassifiedOTUs. Regardlessoftheprimerbiases,
our results show significant (P <0.05) spatiotemporal changes in the molecular abundance and diversity of these heterotrophic
protists. Overall, this study provides a rapid molecular detection tool for Labyrinthulomycetes and expands our current under-
standing of their dynamics controlled by physicochemical gradients in coastal waters. |