Halophilic plant growth-promoting bacterial consortium reshapes soil microbiota to enhance salinity tolerance, antioxidant defense, and yield in Vigna mungo L.
TL;DR
Results demonstrate that the HPGPB consortium enhances salinity tolerance through coordinated physiological, biochemical, and microbiome-associated mechanisms, highlighting the potential of HPGPB consortia as sustainable bioinoculants for improving black gram productivity in salt-affected agroecosystems.
Abstract
Soil salinity is a major abiotic stress that severely restricts crop productivity by disrupting ionic balance, inducing osmotic stress, and promoting oxidative damage. Black gram (Vigna mungo L.), an important pulse crop, is highly sensitive to salinity, resulting in reduced growth, physiological performance, and yield. The present study evaluated the efficacy of a compatible multi-strain HPGPB consortium comprising MKM3 (Halobacillus marinus), MKM4 (Halobacillus halophilus), and MKM11 (Halobacillus halophilus) in enhancing salinity tolerance in two black gram varieties (VBN8 and VBN11) under greenhouse conditions. Plants were subjected to 50 and 100 mM NaCl stress, with and without consortium inoculation, in a completely randomized design. Salinity stress significantly reduced plant growth, photosynthetic pigments, biomass, nutrient uptake, and grain yield, while increasing Na+ accumulation, lipid peroxidation, and osmotic stress markers. Consortium inoculation effectively mitigated these adverse effects by improving plant height, root development, biomass, and grain yield by up to 46 and 38%, respectively, under saline conditions. Consortium-inoculated plants exhibited improved photosynthetic performance, enhanced nutrient uptake and ionic balance, reduced Na+ accumulation and malondialdehyde content, and increased activities of antioxidant enzymes, indicating enhanced salinity tolerance. Among the tested varieties, VBN11 exhibited greater salinity tolerance and a stronger response to consortium inoculation than VBN8. Rhizosphere metagenomic analysis revealed consortium-associated shifts in microbial community structure under saline conditions. Collectively, the results demonstrate that the HPGPB consortium enhances salinity tolerance through coordinated physiological, biochemical, and microbiome-associated mechanisms. These findings highlight the potential of HPGPB consortia as sustainable bioinoculants for improving black gram productivity in salt-affected agroecosystems.