The macroalgal culture collection in Kobe University (KU-MACC) and a comprehensive molecular phylogeny of macroalgae based on the culture strains

Abstract

ABSTRACT The Kobe University Macroalgal Culture Collection (KU-MACC), as a section of the Kobe University Research Center for Inland Seas, distributes cultures of macroalgae to the public under the umbrella of the National BioResource Project of Ministry of Education, Culture, Sports, Science and Technology and Japan Agency for Medical Research and Development, in collaboration with the Microbial Culture Collection of the National Institute of Environmental Studies. KU-MACC principally holds macroalgae (Phaeophyceae, Rhodophyta and Ulvophyceae), but also holds some important related taxa of Schizocladiophyceae and Charophyceae. They are unialgal strains maintained as vegetative thalli and by cryo-preservation. Stock cultures are grown in culture chambers under various temperature conditions in transparent polypropylene vials containing Provasoli’s Enriched Seawater (PES) or PESI medium. The collection includes the “genome strains” of Ectocarpus siliculosus, Chondrus crispus, Chara braunii and their related stains. Depending on the phylogenetic group, DNA sequences of the nuclear rDNA ITS region, chloroplast rbcL, and mitochondrial cox3 genes are determined and used for taxonomy and as genetic tags. Based on the genetic data, molecular phylogenies of Ulvophyceae, Phaeophyceae and Rhodophyta are presented. In the rbcL molecular phylogeny of Ulvophyceae, due to rather limited coverage of culture strains, only members of Ulothricales, Ulvales and Bryopsidales are represented by KU-MACC strains, whereas 10 orders are recognized in the class. The molecular phylogeny of Phaeophyceae based on the cox3 gene showed a tree topology similar to the published multigene molecular phylogeny except for the position of Ishige okamurae, although the bootstrap supports of most nodes were low: Ishigeales branched near the base of Phaeophyceae next to Discosporangiales in the multigene molecular phylogeny, but in the cox3 tree, it showed a long branch and was sister to Fucales. In the molecular phylogeny of Rhodophyta, 14 orders are represented by KU-MACC strains covering about half of currently recognized Bangiophycean and Florideophycean orders.