Phycobilisome composition in Chondrus crispus (Gigartinales, Rhodophyta) from a wild type strain and its vegetatively derived green mutant

doi:2013.28.1.121

Algae > Volume 28(1); 2013 > Article

Algae 2013;28(1): 121-129. doi: https://doi.org/10.4490/algae.2013.28.1.121

M. Lynn Cornish¹, Stephen J. B. O’Leary² and David J. Garbary³^,*

¹Acadian Seaplants Ltd., 30 Brown Avenue, Dartmouth, NS B3B 1X8, Canada
²National Research Council Canada, Aquatic & Crop Resource Development Portfolio, 1411 Oxford Street, Halifax, NS B3H 3Z1, Canada
³Department of Biology, St. Francis Xavier University, Antigonish, NS B2G 2W5, Canada

*Corresponding Author

Email: dgarbary@gmail.com

ABSTRACT

Intact phycobilisomes from a wild-type red Chondrus crispus and its vegetatively derived green mutant were isolated by centrifugation through a discontinuous sucrose density gradient. Pigment composition was subsequently characterized by spectrophotometry. Vegetative thalli of the two strains grown together for six months in the laboratory resulted in different pigment profiles. Two pigmented phycobilisome bands appeared in the sucrose gradient of the wild-type alga, a purple coloured one, and a pink one, whereas only a single blue band appeared in the gradient of the green mutant. Spectrophotometric and fluorescence analyses identified the phycobiliprotein composition of the purple band as the typical phycoerythrin-phycocyanin-allophycocyanin complement in the wild-type, but there was no detectable phycoerythrin present in the blue band of the green mutant. Sodium dodecyl sulphate, preparative polyacrylamide gel electrophoresis analysis confirmed the presence of allophycocyanin subunits in all extracts, but firm evidence of an R-phycoerythrin linker polypeptide in the blue band was missing. These results highlight the ability of C. crispus to adapt to a phycoerythrin deficiency by adjusting light harvesting pigment ratios.

Key words: Chondrus crispus; green mutant; phycobilisomes; phycoerythrin; pigmentation