Metabolomics analysis of Cajanus cajan L. seedlings unravelled amelioration of stress induced responses to salinity after halopriming of seeds

Soil salinity has become a major concern for agriculture. Such constraints not only reinforce the urgent need to understand the underlying mechanisms by which plants cope during salt stress but also to develop cost-effective and farmer friendly halopriming technique to alleviate the adverse effects of salinity to some extent. Metabolomics approach was used to explore different responses to physiological metabolites and pathway variations that occur during salt stress responses in Cajanus cajan L. var. Rabi and to understand the role of halopriming in ameliorating stress at the level of metabolite. Seedlings raised from non-primed and haloprimed seeds, grown in hydroponic solution, were subjected to different concentrations of NaCl. After 21 days, metabolites were extracted, derivatized and analyzed by GC-MS. The data were analysed by different multivariate analyses. Chemometric study of the identified metabolites indicated that the leaves responded most to NaCl induced stress than the stem and root with production of beta-cyano-L-alanine and also increased level of different compatible solutes. O-Acetylsalicylic was also found to increase in all the parts upon facing stress but, such upregulated metabolite production was downregulated in the leaves when the seeds were haloprimed before germination, although many of the metabolites, including beta-cyanoalanine, showed a trend of increase with increase in salt concentrations. Important metabolites produced by C. cajan seedlings in response to salinity were unravelled. Pre-germination haloprimimg of seeds resulted in amelioration of NaCl induced stress, as the levels of stress induced metabolites were lowered.