Chromatic Acclimation: A Many-Coloured Mechanism For Maximizing Photosynthetic Light Harvesting Efficiency
Adam N. Bussell and David M. Kehoe
from: The Cell Biology of Cyanobacteria (Edited by: Enrique Flores and Antonia Herrero). Caister Academic Press, U.K. (2014)
Our understanding of chromatic acclimation, during which the light harvesting antennae or phycobilisomes of cyanobacteria are modified to optimized to maximize photon capture for photosynthesis, has grown remarkably over the past century. Originally a curiosity of a "chameleon cyanobacteria" capable of dramatically altering its pigmentation between red and green in response to changes in the ambient light color, multiple forms of chromatic acclimation are now known to exist and are found in a wide range of species in most habitats on Earth. This ecologically important process gives species that possess it a fitness advantage in environments with fluctuating light color conditions. The form of chromatic acclimation found in deeper marine environments is sensitive to blue and green light and involves the selective substitution of light-absorbing chromophores for these specific wavelengths, while other types of chromatic acclimation are maximally sensitive to the green and red regions of the visible spectrum and involve the reversible replacement of both proteins and chromophores within the phycobilisomes as well as changes in many other cellular processes. Although some progress has been made in unraveling the mechanisms by which these organisms sense and respond to changes in light color conditions, many questions remain to be answered read more ...