A MOLECULAR PHYLOGENY OF THE BANGIOPHYCIDAE (RHODOPHYTA) AND THE ORIGIN OF SECONDARY PLASTIDS

Abstract

Müller, K1, Oliveira, M. C.2, Sheath, R. G.3, Yoon, H. S.4 & Bhattacharya, D.4 1Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1; 2Department of Botany, Institute of Biosciences, University of São Paulo, R. Matão, Travessa 14, N. 321, São Paulo, SP, Brazil, CEP 05508‐900; 3Department of Botany and Dean's Office, University of Guelph, Guelph, Ontario, Canada, N1G 2W1; 4Department of Biological Sciences and Interdepartmental Genetics Program, University of Iowa, Iowa City, IA 52242 USAWe sequenced the nuclear small subunit ribosomal DNA coding region from 20 members of the Bangiophycidae and from two members of the Florideophycidae to gain insights into red algal evolution. A combined alignment of plastid small subunit rDNA, rbcL, and psbA sequences were also studied to complement the understanding of bangiophyte phylogeny and to address red algal secondary symbiosis. Our results are consistent with a monophyletic origin of the Florideophycidae, which form a sister‐group to the Bangiales. Bangiales monophyly is strongly supported, although Porphyra is polyphyletic within Bangia. Bangiophycidae orders such as the Porphyridiales are distributed over three independent red algal lineages. The Compsopogonales sensu stricto, consisting of two freshwater families, Compsopogonaceae and Boldiaceae, forms a well‐supported monophyletic grouping. The single taxon within the Rhodochaetales, Rhodochaete parvula, is positioned within a cluster containing members of the Erythropeltidales. Analyses of plastid sequences show that the plastids of the heterokonts are most closely related to members of the Cyanidiales and are not directly related to cryptophyte and haptophyte plastids. Different data partitions support conflicting topologies regarding the positions of the cryptophytes and haptophytes.