Stress Signaling in Cyanobacteria: A Mechanistic Overview

Abstract

Cyanobacteria are highly diverse, widely distributed photosynthetic bacteria inhabiting various environments ranging from deserts to the cryosphere. Throughout this range of niches, they have to cope with various stresses and kinds of deprivation which threaten their growth and viability. In order to adapt to these stresses and survive, they have developed several global adaptive responses which modulate the patterns of gene expression and the cellular functions at work. Sigma factors, two-component systems, transcriptional regulators and small regulatory RNAs acting either separately or collectively, for example, induce appropriate cyanobacterial stress responses. The aim of this review is to summarize our current knowledge about the diversity of the sensors and regulators involved in the perception and transduction of light, oxidative and thermal stresses, and nutrient starvation responses. The studies discussed here point to the fact that various stresses affecting the photosynthetic capacity are transduced by common mechanisms.

Multi-layer Regulation of Rubisco in Response to Altered Carbon Status in Synechococcus elongatus PCC 7942

“…Three of the downregulated targets were subunits related to ribosomal activities (Synpcc7942_2020, Synpcc7942_2352, and Synpcc7942_2204) (Hood et al, 2016). Two proteins in the AbrB–like family (Synpcc7942_1969 and Synpcc7942_2255) were downregulated, these have been characterized to act as transcription factors involved in carbon/nitrogen balancing in Synechocystis PCC 6803 (Lieman-Hurwitz et al, 2009; Yamauchi et al, 2011; Orf et al, 2016; Rachedi et al, 2020). To better visualize the overall changes in the proteome, we mapped identified proteins with conserved and well-established molecular functions onto a proteomap (Supplementary Fig.…”

Inherent tendency of Synechococcus and heterotrophic bacteria for mutualism on long-term coexistence despite environmental interference

“…The sequenced reads were processed as previously described (see table S16 for the number of reads passed at each step). Here, the DADA2 filters were kept the same as mentioned above except for the maxEE and minFoldParentOverAbundance parameters, which were increased to (5,5) and 2, respectively. The final nonchimeric ASVs were checked for sequence length, and only sequences within a 240-to 380-bp range were taxonomically classified using the nifH database v.1.1.0 (61) with a minimum bootstrap value of 50.…”

Genomics of cyanobacteria: New insights and lessons for shaping our future—A follow-up of volume 65: Genomics of cyanobacteria

“…In the fourth chapter entitled "Functional Genomics of Metalloregulators in Cyanobacteria" Maria Fillat reviewed the major families of metalloregulators in cyanobacteria (Botello-Morte, Gonza ´lez, Bes, Peleato, & Fillat, 2013). The major metal regulator system is composed of Fur-type regulators that comprise three paralogs named FurA (Fur, iron homeostasis), FurB (Zur, Zinc homeostasis) and FurC (PerR, responses to oxidative stress), which control the expression of a wealth of genes involved in exopolysaccharide biosynthesis, phycobilisome degradation, chlorophyll catabolism and nitrogen fixation Gonza ´lez, Sevilla, Bes, Peleato, & Fillat, 2016;Rachedi, Foglino, & Latifi, 2020). These metal-sensing proteins, which harbor metal-binding and DNA-binding domains, are usually allosteric proteins.…”

“…Isar1 accumulates in response to iron starvation and controls at the posttranscriptional level the expression of several genes involved in central cellular processes (photosynthesis, (iron-sulfur) cluster biogenesis, citrate cycle and tetrapyrrole biogenesis). Homologs of IsaR1 are largely conserved in the genomes of cyanobacteria, suggesting that the involvement of this riboregulator in the iron-dependent control of photosynthesis might be conserved in the cyanobacterial phylum (Rachedi et al, 2020).…”