Physiological and Transcriptomics Analyses Reveal that Ascophyllum nodosum Extracts Induce Salinity Tolerance in Arabidopsis by Regulating the Expression of Stress Responsive Genes
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Extracts of the brown alga, Ascophyllum nodosum, are widely used as plant biostimulants to improve growth and to impart tolerance against abiotic stresses. However, the molecular mechanisms by which A. nodosum extract (ANE) mediates stress tolerance are still largely unknown. The aim of this study was to study selected anti-stress mechanisms at the transcriptome level. We show that methanolic sub-fractions of ANE improved growth of Arabidopsis thaliana under NaCl stress; biomass increased by approximately 50% under 100 mM and 150 mM NaCl, relative to the control. Bioassay-guided fractionation revealed that the ethyl acetate sub-fraction of ANE (EAA) had the majority of stress alleviating, bioactive components. Microarray analysis showed that EAA elicited substantial changes in the global transcriptome on day 1 and day 5, after treatment. On day one, 184 genes were up-regulated while this number increased to 257 genes on day 5. On the other hand, 91 and 262 genes were down-regulated on day 1 and day 5, respectively. On day 1, 2.2% of the genes altered were abiotic stress regulated and this increased to 6% on day 5. EAA modulate the expression of number of the genes involved in stress responses, carbohydrate metabolism, and phenylpropanoid metabolism. Thus, our results suggested that bioactive components in the ethyl acetate fraction of A. nodosum induced salinity tolerance in A. thaliana by modulating the expression of a plethora of stress-responsive genes, providing a better understanding of the mechanisms through which ANE mediates tolerance by plants to salinity stress.
KeywordsAscophyllum nodosum Arabidopsis Bioactive compounds Salinity stress Organic extracts
Authors are grateful for the valuable suggestions of Dr. Dhirti Battacharya and Emily Mantin for reading the manuscript. The work reported in this paper was partly funded by Atlantic Innovation Fund program of Atlantic Canada Opportunities Agency and Acadian Seaplants Limited.
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Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be considered as a potential conflict of interest. Authors declare no conflict of interest, financial or non-financial.
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