Nitrate and amino acid availability affects glycine betaine and mycosporine-2-glycine in response to changes of salinity in a halotolerant cyanobacterium Aphanothece halophytica

• Published in: FEMS microbiology letters Vol. 362; no. 23; p. fnv198
• Main Authors: Waditee-Sirisattha, Rungaroon, Kageyama, Hakuto, Fukaya, Minoru, Rai, Vandna, Takabe, Teruhiro
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.12.2015
• Subjects: Accumulation; Amino acids; Amino Acids - metabolism; Aphanothece; Bacterial Proteins - genetics; Betaine - metabolism; Cyanobacteria - chemistry; Cyanobacteria - drug effects; Cyanobacteria - metabolism; Cyclohexanols - metabolism; Glycine; Glycine - analogs & derivatives; Glycine - chemistry; Glycine - metabolism; Glycine - pharmacology; Glycine betaine; Intracellular; Intracellular levels; Levels; Metabolites; Microbiology; Nitrates; Nitrates - metabolism; Osmosis; Salinity; Salinity effects; Salinity tolerance; Salt-Tolerance; Serine; Serine - chemistry; Serine - pharmacology; Stress, Physiological - genetics; Substrates; Sun screens; Time dependence; Transcription; salt stress; halotolerant cyanobacterium; nitrate; glycine betaine; mycosporine-2-glycine; amino acids
• ISSN: 1574-6968; 0378-1097; 1574-6968
• DOI: 10.1093/femsle/fnv198

A halotolerant cyanobacterium Aphanothece halophytica thrives in extreme salinity with accumulation of a potent osmoprotectant glycine betaine. Recently, this cyanobacterium was shown to accumulate sunscreen molecule mycosporine-2-glycine significantly at high salinity. In this study, we investigated effects of nitrate and amino acid provision on the accumulation of glycine betaine and mycosporine-2-glycine. With elevated nitrate concentrations at high salinity, intracellular levels of both metabolites were enhanced. Six-fold high nitrate concentration increased the relative amounts of glycine betaine and mycosporine-2-glycine to be 1.5 and 2.0 folds compared with control condition. Increased levels were time- and dose-dependent manner. Exogenous supply of glycine/serine at high salinity resulted in the similar trends as observed in excess nitrate experiment. Intracellular level of glycine betaine increased ∼1.6 folds with glycine/serine supplementation. These supplementations also caused the increased level of mycosporine-2-glycine, namely 1.4 and 2 folds by glycine and serine, respectively. The transcription of glycine betaine and mycosporine-2-glycine biosynthetic genes was strongly induced under high-nitrate-salt condition. These results suggest the dependence of glycine betaine and mycosporine-2-glycine productions on substrate availability, and the effect of nitrate was possibly associated with stimulation of osmoprotectant increment in this extremophile. Nitrate and amino acid increased the accumulation levels of glycine betaine and mycosporine-2-glycine in response to changes of salinity in a halotolerant cyanobacterium Aphanothece halophytica.