Metabolite expression changes in Kappaphycus alvarezii (a red alga) under hypo- and hyper-saline conditions

Kappaphycus alvarezii is an important red seaweed cultivated as a source of carrageenan and crop growth stimulant. The recurrent salinity fluctuations related to weather variability significantly influence the K. alvarezii cultivation. We report on the evaluation of metabolite changes in K. alvarezii under hypo-(16 ppt), control (32 ppt) and hyper-(48 ppt) saline conditions to unveil the metabolic responses of K. alvarezii under fluctuating salinity. The present study identified a total of 66 different metabolites under studied salinity strengths. The hypo-salinity up-regulated aspartate (0.77 folds) and tyrosine (0.71 folds) and down-regulated phenylalanine (0.51 folds) and proline (0.05 folds). Hyper-salinity up-regulated aspartate (0.64 folds), proline (0.55 folds), serine (0.84 folds) and tyrosine (0.97 folds) in K. alvarezii. Variable importance in the projection (VIP) score plot analysis observed these biomolecules as important metabolites in K. alvarezii under variable saline conditions. Most of the sugars got down-regulated under both saline conditions except mannose which exhibited 0.84 folds up-regulation under hyper-saline condition. K. alvarezii exhibited up-regulation of unsaturated fatty acids under hyper-saline conditions as compared to hypo-saline conditions. These results indicated differential metabolomic responses in K. alvarezii and different mechanisms of salinity acclimatization under control, hypo-and hyper saline conditions.

Automated summary

This study evaluated the metabolite changes in Kappaphycus alvarezii under different salt conditions, revealing differential metabolomic responses and adaptation mechanisms of K. alvarezii under control, hypo-, and hyper-saline conditions.