Grasspea is a legume known as an excellent source of protein and antioxidants, besides other nutritional traits. It is notable for its hardy nature, water-use efficiency and efficacy as a stress-tolerant pulse as compared to major legume species. Despite superior morpho-physiological attributes, this pulse has largely remained outside the realm of systematic molecular profiling.
Three-week-old grasspea (cv. LP-24, Prateek) seedlings were subjected to dehydration over a period of 144 h. This was followed by evaluation of the temporal effects of dehydration at the proteomic, transcriptome and metabolome levels using 2-DE, RNA-seq and GC-MS. Moreover, the 10-day-old subcultured grasspea suspension cells were subjected to dehydration using 10% PEG and metabolites were analysed using MRM-MS. The RNA-seq data was used to generate an in-house database for grasspea (LSDB), which aided in proteomic identifications. Conclusively, we compared the differentially expressed mRNA with of the mRNA products so as to obtain insights into post-transcriptional regulation.
The physiological responses of grasspea were construed by an increase in ROS, disruption in membrane integrity and osmotic imbalance during 72-96 h. The dehydration-induced differential proteomic, transcriptomic and metabolomic analyses, revealed 120 proteins, 5201 genes and 230 metabolites, of various functional classes. The proteogenomic 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 dehydration tolerance and/or avoidance mechanism of grasspea appeared to be enforced through remodulation of DRPs belonging to protein biosynthesis, protein folding, photosynthesis and stress response. We report, for the first time, the dehydration-induced proteogenomic-cum-metabolomic landscape of grasspea, whose genome is yet to be sequenced. The cross-species comparison of the proteomes, transcriptomes and metabolomes provides evidence for marked molecular diversity of grasspea.