Diverse molecular processes of chromatic acclimation in the cyanobacteria phylum

Abstract

The complete genome sequence of cyanobacteria was reported in 1990s as the first genome of photosynthetic organism. Since then, researchers have sequenced several cyanobacterial strains, and utilize them as ‘model’ organisms. However, recent emergence of the next-generation sequencers enables researchers to study diverse ‘non-model’ cyanobacteria strains. We have been studying the diversity of molecular processes of chromatic acclimation in the cyanobacteria phylum and have obtained following results: (1) an existence of the common green and red light-sensing mechanism using phytochrome-related photoreceptor, (2) an existence of two types of signal transduction pathway for chromatic acclimation, and (3) an existence of more than 4 types of gene sets of photosynthetic antenna that are regulated by light colors. Distribution of these light-sensing systems is not correlated with the phylogenetic tree produced based on the sequences of 16S ribosomal RNA, suggesting that these systems are acquired by horizontal gene transfer. Next generation sequencing technology will facilitate our understanding of diverse light-harvesting and light-sensing processes in the cyanobacteria phylum.