Differential metabolite profiles and salinity tolerance between two genetically related brown-seeded and yellow-seeded Brassica carinata lines

Brassica carinata (Ethiopian mustard) has previously been identified as a potential crop species suitable for marginal land in the North American prairies due to its relatively high salt tolerance. Two genetically related B. carinata lines with brown-seeded (BS) and yellow-seeded (YS) phenotypes were assessed for their tolerance to sodium sulfate. Specifically, each line was greenhouse-grown under 0, 50 and 100 mM of salt, and analyzed after four weeks and eight weeks of treatment. Generally, the height of the BS line was greater than the YS line under both salt treatments, indicating enhanced salt tolerance of the BS line. NMR-based metabolite profiling and PCA analyses indicated a more pronounced shift in key stem metabolites after four weeks of treatment with the YS line compared to the BS line. For example, tryptophan and formate levels increased in the YS line after four weeks of 100 mM salt treatment, while proline and threonine levels varied uniquely compared to other metabolites of the lines. Together, the data indicate that the brown-seeded line has greater sodium tolerance than the yellow-seed line, provide clues to the biochemical underpinnings for the phenotypic variation, and highlight the utility of B. carinata as a biorefinery crop for saline land.

► Brassica carinata brown-seeded line exhibits greater salt tolerance than yellow-seeded line.
► Metabolic changes more pronounced in yellow-seeded line after 4 weeks of treatment.
► Tryptophan and formate accumulate in yellow-seeded stems after 4 weeks at high salt.
► Proline and threonine levels varied uniquely compared to other metabolites.
► The brown-seeded genotype has a higher anti-oxidant capacity than the yellow-seeded.