DNA barcoding of the funoran-producing red algal genus Gloiopeltis (Gigartinales) and description of a new species, Gloiopeltis frutex sp. nov.

Abstract

The funoran-producing red macroalga, Gloiopeltis, is known for its commercial uses. Since the economic value of Gloiopeltis is species-dependent, accurate species identification using molecular analysis such as DNA barcoding is important to obtain species-level identification and reveals the hitherto undiscovered biodiversity in Gloiopeltis. In this study, we investigated Gloiopeltis complanata specimens from various locations across Japan and Korea to confirm their relationships with specimens from the type locality in Japan. We employed a combination of molecular analyses using mitochondrial COI-5P as DNA barcoding and plastid rbcL markers, as well as detailed morphological examination of reproductive structures. Genetic analysis revealed the presence of two deeply divergent clades with nucleotide difference of 16.8–17.5% in COI-5P and 6.3–6.8% in rbcL, respectively. The difference in the position of reproductive structure in thallus further supported the subdivision of the Japanese and Korean specimens. As a result, we describe a new species, Gloiopeltis frutex sp. nov., based on the Korean specimens characterized by caespitose and subcylindrical to compressed thallus, slightly flexuous siphonous axis, cruciately divided tetrasporangia scattered over thallus, and slightly swollen cystocarps on proliferations. The results also suggest the necessity of further studies aimed at examining full spectrum of genetic diversity manifested in species of the family Endocladiaceae in detail.