Metabolite profiling and protein quantification to a large library of 96 horsegram (Macrotyloma uniflorum) germplasm

The present study was framed for the assessment of metabolic diversity of 96 diverse horsegram lines derived from 700 germplasm accessions of Pan India. The nutritional component of horsegram germplasm was studied using nuclear magnetic resonance spectroscopy (¹H NMR) and micro-Kjeldal method. Differential range of protein content was found 13-40% in the selected panel. The related wild species Macrotyloma sar-gharwalensis contained highest protein content (40%), and the lowest protein content (13%) was found in IC-120837 and TCR-1439. Seed based ¹H NMR spectroscopy of horsegram discovered 45 different metabolites (17 amino acids, 7 flavonoids, 10 organic acids/phenolic acids/sugar alcohols/steroids, 7 carbohydrades/sugars, and 4 vitamins). The number of total metabolites quantified among diverse horsegram panel ranged from 25-44. The lowest metabolites number was 26 in PLKU-38, while, IC-280031 and IC-139356 lines showed the presence of highest number of metabolites (44). Lines IC-280031 and IC-139356 were found most nutritive amongst selected panel of horsegram germplasm by containing maximum number of quantifiable metabolites during ¹H NMR spectroscopy study. Further, the NMR based data of 96 germplasms was subjected for statistical analysis (PCA, Matrix plot, stacked charts) that revealed the similarities and variations among the whole germplasm. The methionine, sucrose, maltose, riboflavin and myricetin were observed as differential chemo-markers that help to differentiate the horsegram lines of selected panel. This information will further aid in the selection of nutritionally efficient cultivars for proteomics and genomics studies and these lines can be used as nutraceutical food for the prevention of various health ailments including kidney stone.