Dual influence of terrestrial and marine historical processes on the phylogeography of the Brazilian intertidal red alga Gracilaria caudata

Autor(es)

Ayres-Ostrock, Ligia M. ^[1] ; Valero, Myriam ^[2] ; Manger, Stephane ^[2] ; Oliveira, Mariana C. ^[1] ; Plastino, Estela M. ^[1] ; Guillemin, Marie-Laure ^{[2, 3]} ; Destombe, Christophe ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biociencias, Rua Macao 277, BR-05508090 Sao Paulo, SP - Brazil

^[2] Sorbonne Univ, CNRS, UMI 3614, Evolutionary Biol & Ecol Algae, Stn Biol Roscoff, CS 90074, F-29688 Roscoff - France

^[3] Univ Austral Chile, Fac Ciencias, Inst Ciencias Ambientales & Evolut, Valdivia - Chile

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF PHYCOLOGY; v. 55, n. 5 AUG 2019.
• Citações Web of Science: 0

Resumo

In this study, we explored how past terrestrial and marine climate changes have interacted to shape the phylogeographic patterns of the intertidal red seaweed Gracilaria caudata, an economically important species exploited for agar production in the Brazilian north-east. Seven sites were sampled along the north-east tropical and south-east sub-tropical Brazilian coast. The genetic diversity and structure of G. caudata was inferred using a combination of mitochondrial (COI and cox2-3), chloroplast (rbcL) and 15 nuclear microsatellite markers. A remarkable congruence between nuclear, mitochondrial and chloroplast data revealed clear separation between the north-east (from 03 degrees S to 08 degrees S) and the south-east (from 20 degrees S to 23 degrees S) coast of Brazil. These two clades differ in their demographic histories, with signatures of recent demographic expansions in the north-east and divergent populations in the south-east, suggesting the maintenance of several refugia during the last glacial maximum due to sea-level rise and fall. The Bahia region (around 12 degrees S) occupies an intermediate position between both clades. Microsatellites and mtDNA markers showed additional levels of genetic structure within each sampled site located south of Bahia. The separation between the two main groups in G. caudata is likely recent, probably occurring during the Quaternary glacial cycles. The genetic breaks are concordant with (i) those separating terrestrial refugia, (ii) major river outflows and (iii) frontiers between tropical and subtropical regions. Taken together with previously published eco-physiological studies that showed differences in the physiological performance of the strains from distinct locations, these results suggest that the divergent clades in G. caudata correspond to distinct ecotypes in the process of incipient speciation and thus should be considered for the management policy of this commercially important species. (AU)

• Processo FAPESP: 10/50175-3 - Diversidade intraespecífica em algas gracilarioides (Rhodophyta, Gracilariales): biodiversidade marinha
• Beneficiário: Estela Maria Plastino
• Linha de fomento: Auxílio à Pesquisa - Programa BIOTA - Regular
• Processo FAPESP: 11/10189-8 - Estudos populacionais em Gracilaria birdiae (Gracilariales, Rhodophyta): aspectos fisiológicos e moleculares
• Beneficiário: Lígia Maria Ayres Ostrock
• Linha de fomento: Bolsas no Brasil - Doutorado