Complete mitochondrial genome, genetic diversity and molecular phylogeny of Gracilaria salicornia (Rhodophyta: Gracilariaceae)

Gracilaria salicornia is an agarophyte that has been used as food and as a source of agar. We sequenced the complete mitogenome of the species from Malaysia and compared it with the previously described sequence from Hawaii. It had a total length of 25,915 bp, comprising 50 genes [ 25 protein-coding genes (PCGs), 2 rRNA genes and 23 tRNA genes]. It was larger than the Hawaiian sequence (25,272 bp) and possessed three additional tRNAs (trnY, trnR, trnS1). Both G. salicornia sequences had the same start and stop codons for all the PCGs. The genetic distance between the peninsular Malaysian and Hawaiian samples was 0.44% based on 19 PCGs, 0.15% based on 2 rRNA genes and 0.38% based on 19 PCGs + 2 rRNA genes. The phylogram of G. salicornia within Gracilariaceae based on 19 PCGs was congruent with that based on 19 PCGs + 2 rRNA genes.