Phylogenomics, divergence time estimation and trait evolution provide a new look into the Gracilariales (Rhodophyta)

Autor(es)

Lyra, Goia de M. ^{[1, 2]} ; Iha, Cintia ^[3] ; Grassa, Christopher J. ^[1] ; Cai, Liming ^[1] ; Zhang, Hongrui ^[1] ; Lane, Christopher ^[4] ; Blouin, Nicolas ^[4] ; Oliveira, Mariana C. ^[3] ; de Castro Nunes, Jose Marcos ^[2] ; Davis, Charles C. ^[1]

Afiliação do(s) autor(es)

^[1] Harvard Univ Herbaria, Dept Organism & Evolutionary Biol, 22 Divin Ave, Cambridge, MA 02138 - USA

^[2] Univ Fed Bahia, Inst Biol, Lab Algas Marinhas, Rua Barao Jeremoabo S-N, BR-40170115 Salvador, BA - Brazil

^[3] Univ Sao Paulo, Inst Biosci, Dept Bot, R Matao 277, BR-05508090 Sao Paulo, SP - Brazil

^[4] Univ Rhode Isl, Dept Biol Sci, 120 Flagg Rd, Kingston, RI 02881 - USA

• Tipo de documento: Artigo Científico
• Fonte: Molecular Phylogenetics and Evolution; v. 165, DEC 2021.
• Citações Web of Science: 0

Resumo

The Gracilariales is a highly diverse, widely distributed order of red algae (Rhodophyta) that forms a wellsupported clade. Aside from their ecological importance, species of Gracilariales provide important sources of agarans and possess bioactive compounds with medicinal and pharmaceutical use. Recent phylogenetic analyses from a small number of genes have greatly advanced our knowledge of evolutionary relationships in this clade, yet several key nodes were not especially well resolved. We assembled a phylogenomic data set containing 79 nuclear genes, 195 plastid genes, and 24 mitochondrial genes from species representing all three major Gracilariales lineages, including: Melanthalia, Gracilariopsis, and Gracilaria sensu lato. This data set leads to a fullyresolved phylogeny of Gracilariales, which is highly-consistent across genomic compartments. In agreement with previous findings, Melanthalia obtusata was sister to a clade including Gracilaria s.l. and Gracilariopsis, which were each resolved as well-supported clades. Our results also clarified the long-standing uncertainty about relationships in Gracilaria s.l., not resolved in single and multi-genes approaches. We further characterized the divergence time, organellar genome architecture, and morphological trait evolution in Gracilarales to better facilitate its taxonomic treatment. Gracilariopsis and Gracilaria s.l. are comparable taxonomic ranks, based on the overlapping time range of their divergence. The genomic structure of plastid and mitochondria is highly conserved within each clade but differs slightly among these clades in gene contents. For example, the plastid gene petP is lost in Gracilaria s.l. and the mitochondrial gene trnH is in different positions in the genome of Gracilariopsis and Gracilaria s.l. Our analyses of ancestral character evolution provide evidence that the main characters used to delimitate genera in Gracilariales, such as spermatangia type and features of the cystocarp's anatomy, overlap in subclades of Gracilaria s.l. We discuss the taxonomy of Gracilariales in light of these results and propose an objective and practical classification, which is in agreement with the criteria of monophyly, exclusive characters, predictability and nomenclatural stability. (AU)

• Processo FAPESP: 13/11833-3 - Diversidade e filogenia de algas vermelhas (Rhodophyta) de importância econômica e ecológica
• Beneficiário: Mariana Cabral de Oliveira
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Regular