Diversity and origin of carotenoid biosynthesis: its history of co-evolution towards plant photosynthesis.

The development of photosynthesis is a highlight in the progression of bacteria. In addition to the photosystems with their structural proteins, the photosynthesis apparatus consists of different co-factors including essential carotenoids. Thus, the evolution of the carotenoid pathways in relation to the functionality of the resulting structures in photosynthesis is the focus of this review. Analysis of carotenoid pathway genes indicates early evolutionary roots in prokaryotes. The pathway complexity leading to a multitude of structures is a result of gene acquisition including their functional modifications, emergence of novel genes and gene exchange between species. Along with the progression of photosynthesis, pathways of carotenoid co-evolved with photosynthesis according to their advancing functionality. Cyanobacteria with their oxygenic photosynthesis became a landmark for evolutionary events including carotenogenesis. Concurrent with endosymbiosis, the cyanobacterial carotenoid pathways were inherited into algal plastids. In the lineage to Chlorophyta and plants, carotenoids evolved to their prominent role in protection and regulation of light energy input as constituents of a highly-efficient light-harvesting complex. This article is protected by copyright. All rights reserved.