A molecular understanding of complementary chromatic adaptation

Abstract

Photosynthetic activity and the composition of the photosynthetic apparatus are strongly regulated by environmental conditions. Some visually dramatic changes in pigmentation of cyanobacterial cells that occur during changing nutrient and light conditions reflect marked alterations in components of the major light-harvesting complex in these organisms, the phycobilisome. As noted well over 100 years ago, the pigment composition of some cyanobacteria is very sensitive to ambient wavelengths of light; this sensitivity reflects molecular changes in polypeptide constituents of the phycobilisome. The levels of different pigmented polypeptides or phycobiliproteins that become associated with the phycobilisome are adjusted to optimize absorption of excitation energy present in the environment. This process, called complementary chromatic adaptation, is controlled by a bilin-binding photoreceptor related to phytochrome of vascular plants; however, many other regulatory elements also play a role in chromatic adaptation. My perspectives and biases on the history and significance of this process are presented in this essay.

Unique role for translation initiation factor 3 in the light color regulation of photosynthetic gene expression

“…Type III chromatic acclimation is a complex physiological response by which cyanobacteria alter the composition and absorption characteristics of their phycobilisomes to most efficiently use the surrounding light colors (3,4,6). Our results show that the translation initiation factor IF3α is a key component in the light color regulation of this process.…”

“…Cyanobacterial antennae, called phycobilisomes, harvest light energy and channel it to photosynthetic reaction centers (2). In addition, many cyanobacteria sense and respond to the spectral distribution of ambient light and, through a number of processes that are collectively termed chromatic acclimation, alter the abundances of phycobilisome proteins and/ or their associated chromophores to maximize efficient capture of the predominant wavelengths of available light (3)(4)(5)(6). The most studied of these responses, Type III chromatic acclimation (7), is modulated by red and green light, which elicits the accumulation of the chromoproteins phycocyanin or phycoerythrin in the phycobilisomes.…”

Effects of light intensity and quality on phycobiliprotein accumulation in the cyanobacterium Nostoc sphaeroides Kützing

“…Cyanobacteria adapt to changes in light quality by adjusting their PBP ratios and maximizing photosynthesis efficiency (Grossman 2003). Under red light, PE is hardly detectable in Fremyella diplosiphon while PC content is elevated (Grossman et al 2001).…”

Cyanobacterial Contribution to Travertine Deposition in the Hoyoux River System, Belgium

“…Several uni-cyanobacterial strains were isolated from single trichomes and maintained in culture. To test for the ability for complementary chromatic acclimation [52], two subcultures (Isolate 5 and 6) were grown separately under green and red light (using differently coloured plastic filters; adapted from Tandeau de Marsac [53]). The results were positive, showing a predominance of the blue-green phycocyanobilin pigmentation (Fig.…”