Dozens of toxin-related genes are expressed in a nontoxic strain of the dinoflagellate Heterocapsa circularisquama.
The dinoflagellate Heterocapsa circularisquama is lethal to a variety of marine organisms, in particular, commercially important farmed bivalves. Unlike most dinoflagellate toxins, which are polyketides, the only described toxin from H. circularisquama (H2-a) is a porphyrin derivative that functions in light. It is unknown whether H2-a is produced specifically for its lytic properties. We searched for toxin-related genes in the transcriptome of a nontoxic strain of H. circularisquama, and surprisingly found the richest set of toxin-related genes yet described in dinoflagellates. There are 87 distinct expressed sequence tag contigs that encode polyketide synthases and nonribosomal peptide synthases, as well as 8 contigs that are involved in porphyrin biosynthesis. Phylogenomic analysis shows that many toxin-related genes are widely distributed among dinoflagellates. Our data likely indicate a variety of unknown metabolic functions for the toxin-related genes in H. circularisquama because they were identified in a nontoxic strain raised in unialgal culture.
Tovah
T
Salcedo
Ravi J
RJ
Upadhyay
Keizo
K
Nagasaki
Debashish
D
Bhattacharya
D000818:Animals; D053898:Biosynthetic Pathways / Q000235:genetics; D004141:Dinoflagellida / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D020224:Expressed Sequence Tags; D015870:Gene Expression; D017125:Genes, Protozoan; D016013:Likelihood Functions; D010802:Phylogeny; D048630:Polyketide Synthases / Q000235:genetics / Q000378:metabolism; D011166:Porphyrins / Q000096:biosynthesis / Q000235:genetics*; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D012403:Rotifera / Q000382:microbiology; D017422:Sequence Analysis, DNA; D014118:Toxins, Biological / Q000096:biosynthesis / Q000235:genetics*
D011166:Porphyrins; D015800:Protozoan Proteins; D014118:Toxins, Biological; D048630:Polyketide Synthases