Variety-specific nutrient acquisition and dehydration-induced proteomic landscape of grasspea (Lathyrus sativus L.)

Abstract

Grasspea, a stress-resilient pulse crop, has largely remained outside the realm of phytochemical and functional genomics analyses despite its high nutritional significance. To unravel the intervarietal variability in nutrient acquisition of grasspea, we conducted a series of physicochemical experiments using two cultivated varieties, LP-24 and Prateek. The analyses revealed high percentage of starch, cellulose, peroxides, carotenoids, phytic acid and minerals in cv. LP-24, whereas large amounts of protein, soluble carbohydrates and antioxidants in Prateek. To dissect the mechanism of stress tolerance, 3-week-old seedlings of cv. LP-24 and Prateek were afflicted with dehydration for a period of 144 h. The physicochemical indices indicated better adaptation in cv. LP-24, with high abundance of proline, phenolics and flavonoids. Dehydration-responsive proteome landscape of cv. LP-24 revealed 152 proteins with variance at a statistically 94% significance level. The comparative proteomics analysis led to the identification of 120 dehydration-responsive proteins (DRPs), most of which were associated with carbohydrate metabolism, amino acid synthesis, antioxidant reactions and cell defense. We report, for the first time, the dehydration-induced proteome landscape of grasspea, whose genome is yet to be sequenced. The results provide unique insights into variety-specific nutrient acquisition attributes and dehydration-tolerance of grasspea.

BIOLOGICAL SIGNIFICANCE: Grasspea is a great source of protein and antioxidants with nitrogen fixing ability, besides its tolerance to multivariate environmental stress as compared to major legume species. This represents the first report on nutrient profile and health-promoting attributes of grasspea. The cultivars under study are nutritionally enriched that possess high protein, amino acids and health-promoting factors and may therefore be projected as a vital part of a healthy diet. Grasspea is known for its hardy nature, water-use efficiency and efficacy as a stress-tolerant pulse. Further, this study portrays the dehydration-responsive proteomic landscape of grasspea. The proteomics analyses provide crucial insights into the dehydration response, presumably orchestrated by proteins belonging to an array of functional classes including photosynthesis, protein and RNA metabolism, protein folding, antioxidant enzymes and defense. The interplay of the differentially regulated proteins might aid in reinforcing the mechanisms of dehydration avoidance and/or tolerance.