Identification and validation of reference genes for qRT-PCR based studies in horse gram (Macrotyloma uniflorum).

The quantitative real-time polymerase chain reaction (qRT-PCR) is the most sensitive and commonly used technique for gene expression studies in biological systems. However, the reliability of qRT-PCR results depends on the selection of reference gene(s) for data normalization. Horse gram (Macrotyloma uniflorum) is an important legume crop on which several molecular studies have been reported. However, the stability of reference genes has not been evaluated. In the present study, nine candidate reference genes were identified from horse gram RNA-seq data and evaluated in two horse gram genotypes, HPK4 and HPKM317 under six abiotic stresses viz. cold, drought, salinity, heat, abscisic acid and methyl viologen-induced oxidative stress. The results were evaluated using geNorm, Bestkeeper, Normfinder and delta-delta Ct methods and comprehensive ranking was assigned using RefFinder and RankAggreg software. The overall result showed that TCTP was one of the most stable genes in all samples and in genotype HPK4, while in HPKM317 profilin was most stably expressed. However, PSMA5 was identified as least stable in all the experimental conditions. Expression of target genes dehydrin and early response to dehydration 6 under drought stress was also validated using TCTP and profilin for data normalization, either alone or in combination, which confirmed their suitability for qRT-PCR data normalization. Thus, TCTP and profilin genes may be used for qRT-PCR data normalization for molecular and genomic studies in horse gram. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-01104-0.

Ancient orphan legume horse gram: a potential food and forage crop of future.

MAIN CONCLUSION: Tailoring crops to withstand rising temperature and declining precipitation may be unrewarding, therefore the potential of alternative undervalued crops such as horse gram can be explored for safeguarding food and nutritional security with health benefits in the era of climate change. Horse gram [Macrotyloma uniflorum (Lam.) Verdc] under the family Fabaceae, has been cultivated for food, folklore medicine and fodder mainly by rural and tribal communities since prehistoric times in Asian and African countries. This valuable ancient legume not only offers diversification and resilience to agro-ecosystems but it also possesses high adaptation in risk-prone traditional farming systems in marginal environments of semi-arid and arid regions. Being a nutrient dense legume with remedial health-promoting effects due to the presence of various bioactive compounds, it is suitable for the development of functional food as well as for addressing micronutrient deficiencies among poor rural communities. Despite its enormous potential and a growing awareness about the utility of this underutilized crop for future climate adaptation and human well-being, this legume continues to be seriously neglected and labelled as "food of the poors". India is the major producer of horse gram and presently, cultivation of horse gram remains confined to small-scale farming systems as an inter- or mixed crop. This crop is alienated from mainstream agriculture and relegated to a status of "underutilized" due to its limited competitiveness as compared to other commercial crops. Besides a scanty basic research on this crop, no attention has been paid to the factors like improvement of plant type, yield improvement, processing, value addition to suit consumer needs and reduction of anti-nutritional factors, which restricted the diffusion of this crop outside its niche area. The present review therefore is an attempt to compile the meagre information available on crop history, evolution, genetic enhancement, nutritional and health benefits to make the crop competitive and revitalize horse gram cultivation.

Analysis of genetic structure and interrelationships in lentil species using morphological and SSR markers.

Genetic structure and relationships of 130 lentil accessions belonging to six taxa were analysed. For this purpose, seven morphological traits and 31 polymorphic simple sequence repeat (SSR) primers were used for this purpose. Morphological traits grouped lentil accessions into five main clusters. SSR primers collectively amplified 139 polymorphic alleles in a range of 2-10 with an average of 4.48 alleles. The size of amplified alleles varied from 50 to 650 bp. Polymorphism information content (PIC) ranged from 0.02 to 0.85 with an average of 0.46. Neighbour-joining tree grouped accessions broadly according to their taxonomic ranks, except L. culinaris ssp. odemensis. Analysis of molecular variance (AMOVA) revealed that a major portion (82.0%) of genetic variance resided within species, while only 18% resided among species. Bayesian model-based STRUCTURE analysis assigned all accessions into five clusters and showed some admixture within individuals. Cluster analysis showed that cultivated Lens accessions of Ethiopian origin clustered separately, from other cultivated accessions indicating its distinct lineage. Among the analysed lentil species, L. culinaris ssp. odemensis seemed to have conserved genetic background and needs revision of its taxonomic status. Results of present study provide important information on genetic diversity and relationships among different wild and cultivated taxa of lentil. Thus, these results can be useful in designing breeding strategies for future improvement and taxonomic implications in lentil.

Construction of intersubspecific molecular genetic map of lentil based on ISSR, RAPD and SSR markers.

Lentil (Lens culinaris ssp. culinaris), is a self-pollinating diploid (2n = 2x = 14), cool-season legume crop and is consumed worldwide as a rich source of protein (~24.0%), largely in vegetarian diets. Here we report development of a genetic linkage map of Lens using 114 F(2) plants derived from the intersubspecific cross between L 830 and ILWL 77. RAPD (random amplified polymorphic DNA) primers revealed more polymorphism than ISSR (intersimple sequence repeat) and SSR (simple sequence repeat) markers. The highest proportion (30.72%) of segregation distortion was observed in RAPD markers. Of the 235 markers (34 SSR, 9 ISSR and 192 RAPD) used in the mapping study, 199 (28 SSRs, 9 ISSRs and 162 RAPDs) were mapped into 11 linkage groups (LGs), varying between 17.3 and 433.8 cM and covering 3843.4 cM, with an average marker spacing of 19.3 cM. Linkage analysis revealed nine major groups with 15 or more markers each and two small LGs with two markers each, and 36 unlinked markers. The study reported assigning of 11 new SSRs on the linkage map. Of the 66 markers with aberrant segregation, 14 were unlinked and the remaining 52 were mapped. ISSR and RAPD markers were found to be useful in map construction and saturation. The current map represents maximum coverage of lentil genome and could be used for identification of QTL regions linked to agronomic traits, and for marker-assisted selection in lentil.