Protistan parasite QPX of hard-shell clam Mercenaria mercenaria is a member of Labyrinthulomycota

[摘要] ABSTRACT: Biomass of the protistan parasite QPX (quahaug parasite X) of hard-shell clam Mercenaria mercenaria was enriched from in vitro culture. The nuclear gene encoding the 18S RNA of the small-subunit ribosomal (ssu-rDNA) was recoveredusing the polymerase chain reaction (PCR) and sequenced. Phylogenetic analysis clearly showed that QPX is a member of phylum Labyrinthulomycota, within which it appears as a specific relative of Thraustochytrium pachydermum. These results confirmthe provisional assignment of QPX to the Labyrinthulomycota made previously on the basis of morphological and ultrastructural characters found in some, but not all, geographic isolates.

[学科分类] 生物科学（综合）

[关键词] QPX;quahaug parasite X;Mercenaria mercenaria;Hard-shell clam;Small-subunit ribosomal DNA;Labyrinthulomycota;Thraustochytrium pachydermum