Metabolomic analysis of Salvia hispanica (L.) commercial and mutants seeds grown under different irrigation regimes

Chia, Salvia hispanica (L.), is a medicinal and dietary plant species with a high content compounds of industrial and pharmaceutical interest1. Information about metabolites variations in response to external treatments, such as mutation and irrigation, is scarce.
We investigated yield, metabolic profile and antioxidant activity of chia seeds by using a metabolomic approach based on nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. Different chia sources were compared: two commercial (black and white) and four early flowering (G3, G8, G17 and W13.1) mutant genotypes.
The effect of irrigation (100% ET0 and rainfed) was also evaluated on B and G8 varieties. The yield and metabolites profile of early flowering genotypes were different from commercial chia. Although, white chia showed the highest content of omega-3 fatty acids, the high content of nutraceuticals was found in G17 and G8. Irrigation also affected the yield and chemical composition, seed yield was higher in irrigated plots in G8 only (0.255 kgm−2 for I vs 0.184 kgm−2 for NI) while it was very low in B. Organic extracts were mainly composed of mono- and polyunsaturated fatty acids with alpha-linolenic being the most abundant. Irrigated samples showed a higher content of α-linolenic and other fatty acids and a lower oleic/ linoleic ratio.
Polar extracts contained sucrose, methylgalactoside, raffinose and glucose as main sugars, together with caffeoyl derivatives, flavonoids, organic acids, and free amino acids. Antioxidant activity and total polyphenolic content were correlated.
According to our results seeds are a rich source of nutrients, especially of polyunsaturated omega-3 fatty acids that protect from inflammation, enhance cognitive performance and reduce the level of cholesterol3. In particular, G17 and G8 mutants could be a potential source of raw materials for the food/feed industry.