Chemical and genetic differences between Hawaiian lineages of the alga Asparagopsis taxiformis

摘要

Asparagopsis taxiformis is a widely distributed red alga, known locally in Hawai'i as limu kohu. Over the past decade, it was discovered that A. taxiformis is a multiphyletic species, with analysis of mitochondrial DNA revealing several genetically distinct lineages present around the world. A. taxiformis samples from around O'ahu, belonging to the three different lineages found in Hawaiian waters, were collected and subjected to parallel genetic and chemical profiling. Sequencing of the mitochondrial cytochrome oxidase I gene clearly separated the three lineages. In parallel, GC-MS profiling of the samples was conducted in order to determine whether there were any accompanying chemical differences. Analysis of the metabolite profiles using a range of multivariate statistical techniques showed that lineage 4 could be readily differentiated from the other two lineages, lineage 1 and lineage 2, by its chemical profile. Several halogenated metabolites characteristic of lineage 4 were also identified, including methyl bromoiodoacetate, methyl tribromoacetate, carbon tetrabromide, and dibromoacetone.