Becker, Jamie W., Pollak, Shaul, Berta-Thompson, Jessie W., Becker, Kevin W. , Braakman, Rogier, Dooley, Keven D., Hackl, Thomas, Coe, Allison, Arellano, Aldo, LeGault, Kristen N., Berube, Paul M., Biller, Steven J., Cubillos-Ruiz, Andrés, Van Mooy, Benjamin A. S., Chisholm, Sallie W., Ogunseitan, Oladele A. and Marquet, Pablo (2024) Novel isolates expand the physiological diversity of Prochlorococcus and illuminate its macroevolution. mBio, 15 (11). Art.Nr.: e03497. DOI 10.1128/mbio.03497-23.

Preview

Text becker-et-al-2024-novel-isolates-expand-the-physiological-diversity-of-prochlorococcus-and-illuminate-its-macroevolution.pdf - Published Version Available under License Creative Commons: Attribution 4.0. Download (2MB) | Preview

Abstract

Prochlorococcus is a diverse picocyanobacterial genus and the most abundant phototroph on Earth. Its photosynthetic diversity divides it into high-light (HL)- or low-light (LL)-adapted groups representing broad phylogenetic grades—each composed of several monophyletic clades. Here, we physiologically characterize four new Prochlorococcus strains isolated from below the deep chlorophyll maximum in the North Pacific Ocean. We combine these physiological properties with genomic analyses to explore the evolution of photosynthetic antennae and discuss potential macroevolutionary implications. The isolates belong to deeply branching low-light-adapted clades that have no other cultivated representatives and display some unusual characteristics. For example, despite its otherwise low-light-adapted physiological characteristics, strain MIT1223 has low chl b 2 content similar to high-light-adapted strains. Isolate genomes revealed that each strain contains a unique arsenal of pigment biosynthesis and binding alleles that have been horizontally acquired, contributing to the observed physiological diversity. Comparative genomic analysis of all picocyanobacteria reveals that Pcb, the major pigment carrying protein in Prochlorococcus , greatly increased in copy number and diversity per genome along a branch that coincides with the loss of facultative particle attachment. Collectively, these observations support a recently developed macroevolutionary model, in which niche-constructing radiations allowed ancestral lineages of picocyanobacteria to transition from a particle-attached to planktonic lifestyle and broadly colonize the euphotic zone.

Actions (login required)

View Item