Cell wall variability in the green seaweed Codium vermilara (Bryopsidales, Chlorophyta) from Argentine coast.

FERNÁNDEZ, PAULA VIRGINIA; CIANCIA, MARINA; ESTEVEZ, JOSÉ MANUEL

JOURNAL OF PHYCOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2011 vol. 47 p. 802 - 810

0022-3646

Cell walls in the coencocytic green seaweed Codium vermilara (Olivi) Chiaje (Bryopsidales, Chlorophyta) are composed by major amounts of neutral B-(1-4)-D-mannans (Mn), intermediate quantities of sulfated polysaccharides (SPs), which include pyranosic arabinan sulfates (ArpS), pyruvylated galactan sulfates (pGaS), and mannan sulfates (MnS); also minor amounts of O-glycoproteins are present. Although cell wall chemistry in C. vermilara is well understood, how important is the cell wall variability along different geographical locations of the Argentine coast and for temporal points in a single site, was not analyzed before. In this study, cell wall samples of C. vermilara were investigated with regard to their monosaccharide composition (by alditol acetates-gas chromatography couple to mass spectrometry (GC-MS)) and infrared spectra (by Fourier Transformed InfraRed spectroscopy coupled to Principal Component (FTIR-PC) analysis). Samples from three different populations of C. vermilara from Argentine coast (LF, SAO, and BA) that were analyzed showed: 1) an important variation in the relative arabinan content, which increases from north to south, and 2) a measurable degree of cell wall variability in the sulfate distribution between the different sulfated polysaccharides, independently of the amount of each polysaccharide present and of total sulfate content. When cell wall composition was analyzed over three consecutive years in a single geographical location (LF), the quantity of Mn and overall sulfate content on SPs remained constant, whereas pGaS:ArpS molar ratio changed over the time. Besides, similar cell wall composition was found between actively-growing and resting zones of the thallus, suggesting that cell wall composition in a single time point is independent of growth stage and development. Overall, these results suggest that C. vermilara has developed a mechanism to adjust the total level of cell wall sulfation by modulating ArpS:pGaS:MnS molar ratio and also by adjusting the of sulfation level in each type of polymer, whereas non-sulfated Mn, as the main structural polysaccharide, does not change over the time or growing stage.