Affiliation:
1. Department of Biology, Washington University, St. Louis, Missouri, USA
2. Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, Missouri, USA
Abstract
ABSTRACT
At the genome level,
Synechococcus elongatus
UTEX 2973 (
Synechococcus
2973) is nearly identical to the model cyanobacterium
Synechococcus elongatus
PCC 7942 (
Synechococcus
7942) with only 55 single nucleotide differences separating the two strains. Despite the high similarity between the two strains,
Synechococcus
2973 grows three times faster, accumulates significantly more glycogen, is tolerant to extremely high light intensities, and displays higher photosynthetic rates. The high homology between the two strains provides a unique opportunity to examine the factors that lead to increased photosynthetic rates. We compared the photophysiology of the two strains and determined the differences in
Synechococcus
2973 that lead to increased photosynthetic rates and the concomitant increase in biomass production. In this study, we identified inefficiencies in the electron transport chain of
Synechococcus
7942 that have been alleviated in
Synechococcus
2973. Photosystem II (PSII) capacity is the same in both strains. However,
Synechococcus
2973 exhibits a 1.6-fold increase in PSI content, a 1.5-fold increase in cytochrome
b
6
f
content, and a 2.4-fold increase in plastocyanin content on a per cell basis. The increased content of electron carriers allows a higher flux of electrons through the photosynthetic electron transport chain, while the increased PSI content provides more oxidizing power to maintain upstream carriers ready to accept electrons. These changes serve to increase the photosynthetic efficiency of
Synechococcus
2973, the fastest growing cyanobacterium known.
IMPORTANCE
As the global population increases, the amount of arable land continues to decrease. To prevent a looming food crisis, crop productivity per acre must increase. A promising target for improving crop productivity is increasing the photosynthetic rates in crop plants. Cyanobacteria serve as models for higher plant photosynthetic systems and are an important test bed for improvements in photosynthetic productivity. In this study, we identified key factors that lead to improved photosynthetic efficiency and increased production of biomass of a cyanobacterium. We suggest that the findings presented herein will give direction to improvements that may be made in other photosynthetic organisms to improve photosynthetic efficiency.
Funder
National Science Foundation
Publisher
American Society for Microbiology
Cited by
85 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献