Comparative transcriptome profiling of Salinicola sp MFB021 in response to salinity stress

Abstract

newline Salinicola sp. MFB021 is a moderately halophilic, aerobic, bacterium that grows in a newlinewide salinity range of 0.5 to 30% (wt/vol) NaCl, which belongs to Halomonedacea family. newlineThe aim of this study was to analyse the comparative transcriptome profiling of Salinicola sp. newlineMFB021 to identify novel genes and their corresponding pathways exclusively expressed newlineunder various levels of salinity stress. Differential gene expression analysis of Salinicola sp. newlineMFB021 will improve our understanding of molecular events involved in lower to higher newlinelevel transition of growth under salt tolerance (1M to 4M NaCl); identified by de novo newlinetranscriptome analysis using RNA sequencing. Whole transcriptome sequencing of four newlinecDNA libraries representing the growth transition of Salinicola sp. MFB021 in 1M NaCl, 1M newlineto 2.5M NaCl, 2.5M to 4M NaCl and 1M to 4M NaCl was performed. RNA-Seq reads for newlineeach cDNA library generated approximately 9 to 10 million reads. De novo transcriptome newlineassembly generated from RNA-Seq data of all the stages resulted in 5691 contigs, of which newline4783 transcripts were expressed in all the four stages. The number of transcripts that were newlineexclusively expressed in each stage was 108 for M1, 167 for M1-M2.5, 180 for M2.5-M4 and newline75 for M1-M4. During hyper-salinity stress, there was representation of K+ uptake and Na+ newlineefflux system and osmolyte synthesis was less active than other regulating metabolic newlineprocesses, whereas the genes involved in bet operon (glycine-betaine) was actively newlinetranscribed during 1M to 2.5M NaCl transition. During 2.5M to 4M NaCl transition, genes newlineinvolved in metabolic process such as other symporters/antiporters, signal newlinetransduction/repair/sigma factors, ABC transporters and other transporters, efflux system and newlineiron chelating and transporting system were over expressed. The up-regulated genes in both newline2.5M to 4M NaCl and 1M to 4M NaCl transition stages were genes involved in newlinesalt/osmotic/stress/starvation responses.