Photoperiod length paces the temporal orchestration of cell cycle and carbon‐nitrogen metabolism in Crocosphaera watsonii. (10th July 2013)

• Record Type: Journal Article
• Authors: Dron, Anthony; Rabouille, Sophie; Claquin, Pascal; Talec, Amélie; Raimbault, Virginie; Sciandra, Antoine; Vicente, Miguel; Ayala, Juan; Daley, Daniel
• Is Part Of: Environmental microbiology. Volume 15:Number 12(2013:Dec.)
• Page Start: 3292
• Page End: 3304
• Publication Date: 2013-07-10
• Subjects: Microbial ecology -- Periodicals; Environmental Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1462-2920.12163
• Languages: English
• ISSNs: 1462-2912

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>We analysed the effect of photoperiod length (PPL) (16:8 and 8:16 h of light–dark regime, named long and short PPL, respectively) on the temporal orchestration of the two antagonistic, carbon and nitrogen acquisitions in the unicellular, diazotrophic cyanobacterium <italic>Crocosphaera watsonii</italic> strain WH8501 growing diazotrophically. Carbon and nitrogen metabolism were monitored at high frequency, and their patterns were compared with the cell cycle progression. The oxygen‐sensitive N₂ fixation process occurred mainly during the dark period, where photosynthesis cannot take place, inducing a light–dark cycle of cellular C : N ratio. Examination of circadian patterns in the cell cycle revealed that cell division occurred during the midlight period, (8 h and 4 h into the light in the long and short PPL conditions, respectively), thus timely separated from the energy‐intensive diazotrophic process. Results consistently show a nearly 5 h time lag between the end of cell division and the onset of N₂ fixation. Shorter PPLs affected DNA compaction of <italic>C. watsonii</italic> cells and also led to a decrease in the cell division rate. Therefore, PPL paces the growth of <italic>C. watsonii</italic>: a long PPL enhances cell division while a short PPL favours somatic growth (biomass production) with higher carbon and nitrogen cell contents.</p> </abstract>