Salt Acclimation of Cyanobacteria and Their Application in Biotechnology

Abstract

The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanisms are less well understood. Here, we briefly review recent advances in the identification of salt acclimation processes and the essential genes/proteins involved in acclimation to high salt. This knowledge is of increasing importance because the necessary mass cultivation of cyanobacteria for future use in biotechnology will be performed in sea water. In addition, cyanobacterial salt resistance genes also can be applied to improve the salt tolerance of salt sensitive organisms, such as crop plants.

Poly[(R)-3-hydroxybutyrate] production under different salinity conditions by a novel Bacillus megaterium strain

“…This "salt-out-cytoplasm" strategy is especially important to balance the osmotic stress when the salt concentration is extremely high [19,20].…”

Aquaporin-deficient mutant of Synechocystis is sensitive to salt and high-light stress

“…4). Salt-induced transcription of genes for chaperone HspA [23], sensory histidine kinase Hik34 [24], response regulator Rre37, which is involved in regulation of glycogen synthesis [25], glucosylglycerol transporter GgtB [1], was diminished in the mutant cells. At the same time, transcription of other genes was enhanced.…”

“…At the same time, transcription of other genes was enhanced. The letter set of genes encode chaperone DnaJ, glucosylglycerol-phosphate synthase GgpS, glycerol-3-phosphate dehydrogenase GlpD (GgpS and GlpD are involved in the salt-and osmo-induced synthesis of an osmoprotector, glucosylglycerol [1]). Similar effect of the mutation in the aqpZ gene had been observed in Synechocystis under hyperosmotic stress [5].…”

“…PCC 6803 (hereafter Synechocystis) belongs to the group of moderately halotolerant cyanobacteria [1] that resists up to 0,6 M NaCl, which is equivalent to seawater conditions [2]. Sodium is an essential element for the cell metabolism in cyanobacteria, however, the excess amounts of sodium cause salinity stress.…”

Mechanical characterization system of cyanobacteria using a robot integrated microdluidic chip

“…PCC 6803, which is a few micrometers in diameter, is commonly used as model organisms for analyzing photosynthesis and its stress adaptation mechanisms to culture environment [1][2] [3]. Particularly, some ion channels on the cell membrane are reported to be deeply related with osmotic adaptation [4].…”