Dr. Kavita Singh Chaudhary,
Assistance Professor
Govt. P. G. College, Noida
Abstract
Climate change is aggravating occurrence, extent and co-occurrence of abiotic stresses like drought, salinity and heat hence posing an immense challenge to crop productivity and soil health across the world. These stresses nearly always interact in native agroecosystems, but most mitigation approaches have focused on individual responses to stress and the microbiology of stress. This review provides a critical synthesis of the current developments in the field of agricultural microbiology as as far as multi-stress tolerance microbial inoculants are concerned on the crop plants. It specifically focuses on microbiological processes, inter-microbial community behavior and cross-tolerance effects when subjected to combined abiotic stress conditions. The role of stress-tolerant plant-growth-promoting rhizobacteria, endophytic bacteria, arbuscular mycorrhizal fungi, and useful fungi in strengthening the ability of plants to withstand drought, salinity and heat was evaluated. Single-taxon, and consortium-based approaches are discussed, with their merits and shortcomings being discussed. The principal microbial pathways that support multi-stress tolerance such as ACC deaminase activity, phytotranscriptional modulation, exopolysaccharide and osmolyte production, antioxidant enzyme induction, volatile organic compound signaling, and transcriptional reorganization of host stress-responsive genes are discussed. It also explores the role of microbial network features like functional redundancy, keystone taxa and community stability in propelling phytomicrobiome stability under complicated stress conditions. The findings of metagenomics, metatranscriptomics and systems-biology studies are combined to provide an insight into how the microbiome assemble, how they modify functions in response to multifaceted stresses, and how plants and microbes coordinate themselves. Lastly, key problems in translation such as rhizosphere competence, interactions of native microbiome, formulation stability, and unequal performance in the field are crucially assessed. Future research directions that would establish next -generation ecologically sound multi-stress-tolerant microbial inoculants are suggested. Taken together, this review highlights the dominant role of microbiome-based strategies in ensuring the ability of agriculture to be sustainable and climate-resilient.
Keywords: Multi-stress tolerance, Plant–microbe interactions, Microbial consortia, Abiotic stress, Rhizosphere microbiome.