Journal Article

Transcriptional and metabolomic analysis of Ascophyllum nodosum mediated freezing tolerance in Arabidopsis thaliana

Critchley, A.T, Prithiviraj, B, Ji, X, Hiltz, D, Benkel, B, Nair, P, Kandasamy, S, Hodges, M.D, Zhang, J, Kirby, C

2012

Overview

Background: We have previously shown that lipophilic components (LPC) of the brown seaweed Ascophyllum nodosum (ANE) improved freezing tolerance in Arabidopsis thaliana. However, the mechanism(s) of this induced freezing stress tolerance is largely unknown. Here, we investigated LPC induced changes in the transcriptome and metabolome of A. thaliana undergoing freezing stress.Results: Gene expression studies revealed that the accumulation of proline was mediated by an increase in the expression of the proline synthesis genes P5CS1 and P5CS2 and a marginal reduction in the expression of the proline dehydrogenase (ProDH) gene. Moreover, LPC application significantly increased the concentration of total soluble sugars in the cytosol in response to freezing stress. Arabidopsis sfr4 mutant plants, defective in the accumulation of free sugars, treated with LPC, exhibited freezing sensitivity similar to that of untreated controls. The 1H NMR metabolite profile of LPC-treated Arabidopsis plants exposed to freezing stress revealed a spectrum dominated by chemical shifts (δ) representing soluble sugars, sugar alcohols, organic acids and lipophilic components like fatty acids, as compared to control plants. Additionally, 2D NMR spectra suggested an increase in the degree of unsaturation of fatty acids in LPC treated plants under freezing stress. These results were supported by global transcriptome analysis. Transcriptome analysis revealed that LPC treatment altered the expression of 1113 genes (5%) in comparison with untreated plants. A total of 463 genes (2%) were up regulated while 650 genes (3%) were down regulated.Conclusion: Taken together, the results of the experiments presented in this paper provide evidence to support LPC mediated freezing tolerance enhancement through a combination of the priming of plants for the increased accumulation of osmoprotectants and alteration of cellular fatty acid composition. © 2012 Nair et al.; licensee BioMed Central Ltd.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Accumulation / Agriculture / Algae / Analysis / Animal Genetics and Genomics / Arabidopsis / Arabidopsis - drug effects / Arabidopsis - genetics / Arabidopsis - physiology / Arabidopsis thaliana / Ascophyllum / Ascophyllum - chemistry / Ascophyllum - physiology / Ascophyllum nodosum / Biomedical and Life Sciences / Carbohydrate Metabolism / carboxylic acid / Chemical priming / Cold / Colleges & universities / cytosol / DNA microarrays / down regulation / Experiments / fatty acid / Fatty acids / Freezing / Freezing tolerance / gene expression / Gene Expression Profiling / Genes / Genetic aspects / Genetic research / Genetic transcription / Genomics / Hardiness / Heat / heteronuclear multiple bond correlation / heteronuclear single quantum coherence / Hot Temperature / Hydrophobic and Hydrophilic Interactions / Life Sciences / lipid composition / lipophilicity / Medical equipment and supplies industry / Medical test kit industry / Metabolite profiling / Metabolites / Metabolomics / Metabonomic analysis / Microarray analysis / Microarrays / Microbial Genetics and Genomics / Mutation / nuclear magnetic resonance spectroscopy / Organic acids / osmotic stress / P5CS1 gene / P5CS2 gene / plant gene / Plant Genetics and Genomics / Plant genomic / Plants / Polyols / ProDH gene / Proline / Proline - biosynthesis / Proline - metabolism / proline dehydrogenase / Proteins / Proteomics / proton nuclear magnetic resonance / pyrroline 5 carboxylate reductase / Research Article / Salinity / sfr4 gene / Solubility / Soluble sugars / Sugar / sugar alcohol / Temperature / Transcription, Genetic / transcriptomics / upregulation / Wheat