Genomic and phylogenetic analyses of the domoic acid biosynthesis genes in the benthic diatom Nitzschia navis-varingica (Bacillariophyceae).

Through genome sequencing and comparative genomic analysis, candidate genes involved in the biosynthesis of domoic acid (DA) in the benthic diatom Nitzschia navis-varingica were identified. Orthologs of DA biosynthesis genes (dabA, dabB, dabC, and dabD), originally identified in Pseudo-nitzschia species, were detected in N. navis-varingica strains. However, due to the draft level of our genomes, the tandem gene cluster organization present in the Pseudo-nitzschia species cannot be determined in N. navis-varingica strains. In addition, two copies of dabC were found in N. navis-varingica strains, suggesting potential functional significance in the biosynthesis of DA and its isoforms. The identification of dab genes in N. navis-varingica provides a foundation for further studies on the origin, evolution, and transcriptional regulations of DA biosynthesis in this benthic diatom.