Genetic Dissection of Phosphorous Uptake and Utilization Efficiency Traits Using GWAS in Mungbean

Mungbean (Vignaradiata L. Wilczek) is an early maturing legume grown predominantly in Asia for its protein-rich seeds. P deficiency can lead to several physiological disorders which ultimately result in a low grain yield in mungbean. The genetic dissection of PUpE (Puptake efficiency) and PUtE (P utilization efficiency) traits are essential for breeding mungbean varieties with a high P uptake and utilization efficiency. The study involves an association mapping panel consisting of 120 mungbean genotypes which were phenotyped for total dry weight, P concentration, total P uptake, and P utilization efficiency under low P (LP) and normal P (NP) conditions in a hydroponic system. A genotyping-by-sequencing (GBS) based genome-wide association study (GWAS) approach was employed to dissect the complexity of PUpE and PUtE traits at the genetic level in mungbean. This has identified 116 SNPs in 61 protein-coding genes and of these, 16 have been found to enhance phosphorous uptake and utilization efficiency in mungbeans. We identified six genes with a high expression (VRADI01G04370, VRADI05G20860, VRADI06G12490, VRADI08G20910, VRADI08G00070 and VRADI09G09030) in root, shoot apical meristem and leaf, indicating their role in the regulation of P uptake and utilization efficiency in mungbean. The SNPs present in three genes have also been validated using a Sanger sequencing approach.

EFFECTS OF COMBINED INOCULATION OF BAMBARA GROUNDNUT (Vigna subterranean L. Verdc.) WITH GLOMUS MOSSEA AND BRADYHRHIZOBIUM JAPONICUM ON NITROGEN AND PHOSPHOROUS UPTAKE IN SHOOT, PLANT BIOMASS, LEAF CHLOROPHYLL AND MYCORRHIZAL INOCULATION EFFICIENCY (MIE).

The response of Bambara groundnut to co-inoculation with Abuscular mychorrhizal fungi (G. mossea) and Bradhyrhizobium japonicum (strain USDA110) with regard to leaf chlorophyll, percentage shoot nitrogen and phosphorus, nodule weight and plant biomass was studied. Bambara plants were grown under screen house conditions in pots. Plants were inoculated with 1ml of B. japonicum USDA 110 strain (109 cfu /ml), Mychorrizal was applied to the plants 10g, and 20g (90 spores/g) and water was applied at 10ml, 20 ml and 50ml every other day. The obtained results showed that dual inoculation activity was able to improve both nitrogen and phosphorus in plant shoot, MIE, but did not improve biomass and leaf chlorophyll when compared with plants subjected to single inoculation with only G. mossea and only B. japonicum. More Nitrogen and Phosphorus was retained in the shoot of plants co-inoculated with B. japonicum and 20g G. mossea when given 50ml of water and also had higher biomass. Leaf chlorophyll reduced in plants as flowering approached. B. japonicum was able to positively influence and establish symbiosis with G.mossea and synergistically effectively act as “mycorrhiza helper bacteria” (MHB) when both were co-inoculated in Bambara plant.