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Horsegram (Macrotyloma uniflorum) - an important, self-pollinated food legume, however due to limited genomic and genetic resources the genetic improvement could not be achieved as compare to other major legumes. Our work aims at finding novel microsatellite markers and their use for the construction of a linkage map from 157 individuals of F9 recombinant inbred lines (RILs) of horsegram. The determinate growth habit and plant height are important traits for its suitability for different cropping systems. The genotypic data were generated by screening 2 395 molecular markers, of which 600 (25.05 %) polymorphic markers were selected. Two-hundred eighty-seven markers were mapped on ten linkage groups (LGs) at a log of odds (LOD) of 3.5 straddling 796.76 cM with 2.78 cM of marker density. For the identification of the quantitative trait loci (QTLs), the phenotypic data recorded on the RILs for the plant height and growth habit were analysed using the statistical tools JoinMap® and Windows QTL cartographer, based on the composite interval mapping (CIM) technique. Across the ten linkage groups, we detected four QTLs (LOD ≥ 2.5) for four traits. All the traits were major QTLs as indicated by the percentage of phenotypic variance (PVE) (≥ 10%) that ranged from 13.5% to 40.3%, therefore, this is very important information which can be used in marker-assisted selection (MAS). The present genomic information generated in this orphan crop, thus, provides the base for genetic improvements by devising molecular breeding strategies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Horsegram (Macrotyloma uniflorum) is a legume species that is widely distributed throughout the Indian subcontinent. It is considered to be an important dietary protein supplement and nutraceutical. Horsegram has a great potential for fulfilling future pulse crop demand due to its inherent ability to grow under very low moisture conditions. However, the genome structure and organization of this crop is poorly understood, thereby limiting the effective use of gene resources for genetic improvement. We report here our construction of the first framework linkage map of horsegram, consisting of 211 molecular markers (157 SSR, 39 RAPD, 8 ISSR and 7 COS), using a mapping population of 190 recombinant inbred lines derived from a cross between parental lines HPK4 and HPKM249. The map comprises 13 linkage groups (LGs) that span 1423.4 cM, with a mean marker interval of 9.6 cM. Phenotypic data for eight agronomic traits were recorded for 2 years and utilized to detect associated quantitative trait loci (QTLs). Five QTLs for four traits related to drought (days to temporary wilting, root length) and yield (numbers of seeds per plant, days to maturity) were detected on five LGs, with an LOD threshold of 4.0. The linkage and QTL analysis reported here provides useful information for future research work pertaining to the construction of highly enriched genetic maps as well as to the development of drought-resistant and high-yielding varieties of horsegram using marker-assisted selection. [ABSTRACT FROM AUTHOR]

Horsegram [ Macrotyloma uniflorum Lam (Verdc.)] is an undervalued and under studied legume though is a good source of proteins, carbohydrates and energy. Drought is an abiotic stress that effects plant development and ecosystem sustainability. Drought is expected to become more common in the future as a result of climate change. Horsegram is known to withstand drought, salt and heavy metal stress. In the past few decades application of genome-wide association studies (GWAS) to explore complex traits has risen in popularity. Considering the above mentioned factors drought tolerance ability of horsegram germplasm was investigated in 96 diverse horsegram lines with GWAS by exploring 20241 SNPs. Highest number of SNPs were found to be located in intergenic regions (43.8%) followed by intronic SNPs (21.6%). In this investigation three drought tolerant representing parameters were selected for QTL identification. In the present study, we identified different SNPs associated with QTLs governing these traits, which involved in drought stress response of horsegram plant. Seven QTLs were found to be associated with relative water content in horsegram whereas for root volume and root length 4 and 8 QTLs were found respectively. By using horsegram database of Kazusa DNA research institute Japan, we identify the genes present on these marker sites which were found to be involved in many biochemical pathways related to plant abiotic stresses. Many of these genes were previously characterized and few uncharacterized genes were also found controlling these traits. These findings will help in identifying new mechanisms responsible for plant drought stress tolerance in future. [ABSTRACT FROM AUTHOR]