Life history of Leathesia marina (Chordariaceae, Phaeophyceae) from the Atlantic Patagonian coast, an integrative approach

POZA, AILÉN M.; SANTIAÑEZ, W.J.E.; CROCE, M. EMILIA; GAUNA M. CECILIA; KOGAME, K.; PARODI, ELISA R.

Townsville

Conferencia; 31 ASPAB Conference; 2017

We evaluated the life history of Leathesia marina in culture, through an integrated approach based on morphology, ploidy and phylogenetic analyses. Sporophytes were collected in two localities of Atlantic Patagonia. Fertile sections were cultured under long day (LD) and short day (SD) conditions.To determine nuclear ploidy of each phase, DNA contents of individual nuclei were quantified by epifluorescence microscopy. For phylogenetic analyses, DNA was extracted from silica gel-dried samples, and cox3 and rbcL genes were amplified and sequenced. The cultured thalli released spores which developed into hemispherical microthalli (n) with a mean fluorescent cross-sectional area of 1.88 μm2, similar to the morphology of the sporophyte (2n). In SD conditions, the hemispherical microthalli formed plurilocular gametangia that asexually produced prostrate uniseriate filaments with a mean fluorescent cross-sectional nuclear area of 1.78 μm2. The plurilocular gametangia of these prostrate microthalli released gametes that merged, forming new macroscopic thalli. Phylogenetic analyses based on single gene and concatenated data set confirmed the identity of the Argentinian specimens as Leathesia marina. The Argentinian L. marina from the two localities were genetically similar and formed a well-supported clade with its conspecifics from New Zealand, Germany and Japan, suggesting that the species is widely distributed.