Identification of Gracilariaceae (Rhodophyta) of central Portugal by histological and genetic methods

Abstract

This study aims to identify different populations of Gracilariaceae collected from the central coast of Portugal through light microscopy, anatomical observations and genetic tools, essential approaches to correctly assign species identity. Samples were obtained from Ria de Aveiro (AV), Figueira da Foz (FFBC, FFMD), and Lagoa de Óbidos (LOBR, LOEV, LOBS). Although histological observations offered a visual representation of the characteristic pseudoparenchymatous organization, they did not allow a clear distinction among the species. The amplification of a ∼700 bp fragment of the mitochondrial cytochrome oxidase I gene, and its sequencing enabled us to assign the populations FFBC and LOBS to Gracilaria gracilis, and the populations AV, FFMD, LOBR, and LOEV to Agarophyton vermiculophyllum. This contribution will help phycologists to correctly identify the Portuguese populations of Gracilaria sensu lato at the species level, which will be crucial in ensuring that future studies and industrial exploration accurately target the correct species.