Systematic Review on Harnessing Mangrove-associated Rhizobacteria for Abiotic Stress Tolerance in Horticultural Crops: A Sustainable Biotechnological Approach
Climate change has escalated the frequency of abiotic stresses such as heat, drought, salinity, and heavy metal toxicity, which adversely affect the productivity of horticultural crops and food security. Mangrove ecosystems are home to the Plant Growth-Promoting Rhizobacteria (PGPR) that are specially adapted to survive even in the most extreme environmental conditions. These PGPRs from mangroves are an eco-friendly way to raise the stress tolerance level of horticultural crops. The paper reviews current research on the functional traits of PGPR derived from mangroves, including nutrient solubilization, phytohormone production, ACC deaminase activity, and production of metabolites that aid stress alleviation. The paper also highlights recent advancements in molecular “omics” tools–genomics, transcriptomics, proteomics, and metabolomics–used for elucidating the interaction mechanisms between PGPR and plants. The study was primarily focused on experiments performed in the lab and greenhouse. Field research is also gaining traction. Mangrove PGPR employ various mechanisms for stress release, including nitrogen fixation, siderophore production, EPS synthesis, osmoprotection, and antioxidant enzyme induction. Application of such PGPR has improved the drought and salinity tolerance of horticultural crops such as tomato, cucumber, banana, and their close relatives. Omics-based studies unravel the complexity of the regulatory network that controls both stress signaling and nutritional uptake. Although the laboratory results are good, a problem remains in open fields due to environmental variability and crop-specific responses. To ensure reliable performance, PGPR consortia need optimization of strategy formulation and delivery systems. Mangrove-associated PGPRs are a promising approach to improve climate change resilience in horticultural crops. Much work still remains to be done on large-scale field trials, advanced bioformulations, and deployment of current biotechnology approaches before general agricultural benefits can be realized.