Two forms of phycobilisomes in the Antarctic red macroalga Palmaria decipiens (Palmariales, Florideophyceae)

• Published in: Physiologia Plantarum
• Main Authors: Lüder, Ulrike H., Knoetzel, Jürgen, Wiencke, Christian
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Antarctic; The Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1034/j.1399-3054.2001.1120416.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1034%2Fj.1399-3054.2001.1120416.x; https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.2001.1120416.x

The phycobilisomes (PBS), the light‐harvesting antennae, from the endemic Antarctic red macroalga Palmaria decipiens were isolated on discontinuous sucrose gradients in two discrete bands and not in one as expected. To exclude methodical faults, we also isolated PBS from the temperate Palmaria palmata and the unicellular red algae Porphyridium cruentum and Rhodella violacea . In P. palmata the PBS were separated in two discrete bands, whereas the PBS from Porphyridium and Rhodella were found in one band. The double‐banded PBS (PBS up and PBS low ) from P. decipiens were further characterized by absorption and fluorescence spectroscopy, native and SDS‐PAGE as well as by negative staining. The phycobiliproteins RIII‐phycoerythrin, RI‐phycocyanin and allophycocyanin were identified and 3 γ ‐subunits were described. The PBS up and PBS low showed no significant differences in their absorption spectra and phycobiliprotein ratios although the negative stained PBS low were smaller. Differences were found in their low molecular mass subunit complexes, which are assumed to be r‐phycoerythrin. The polypeptide pattern of the PBS up and PBS low showed no differences in the molecular masses of their subunits and linker polypeptides, but in their percentage distribution. The results suggest that the PBS low is a closer packed and PBS up a little more loosely aggregated hemiellipsiodal PBS form. We discuss the ecophysiological function of two PBS forms in P. decipiens and suggest advantages in the rapid acclimation to changes in environmental light conditions.