Rhizosphere Microbiome–Biofertilizer Nexus: Integrating Biological Inputs and Abiotic Stress Tolerance Mechanisms in Horticultural Crops

Abstract

Climate change is intensifying abiotic stresses such as drought and salinity, threatening horticultural productivity worldwide and creating an urgent need for sustainable, ecologically resilient production strategies. Using a structured narrative review approach, this study synthesizes peer-reviewed literature published between 2020 and 2026, retrieved from Scopus, Web of Science, PubMed, and Google Scholar; to evaluate how beneficial soil microorganisms and biological inputs enhance horticultural crop performance under stress. The objective is to examine the efficacy of Plant Growth-Promoting Rhizobacteria (PGPR), Arbuscular Mycorrhizal Fungi (AMF), and other microbial inoculants in improving growth and yield in tomato (Solanum lycopersicum), mediating drought tolerance in grapevine (Vitis vinifera) through osmotic adjustment and antioxidant defense, and mitigating salinity-induced ionic toxicity in date palm (Phoenix dactylifera) via halotolerant microbial mechanisms. Unlike previous reviews that typically examine a single crop, a single stress type, or a single microbial group in isolation, this review integrates rhizosphere microbial diversity, biofertilizer function, and multi-stress tolerance mechanisms within a single conceptual framework, the Rhizosphere Microbiome–Biofertilizer Nexus. Findings show that rhizosphere microbial diversity functions as a central mediator of nutrient cycling and stress signaling. Comparative evidence across studies further indicates that microbiome engineering and synthetic microbial consortia represent an emerging frontier in horticultural science, although consistent field performance remains constrained by formulation and site-specific limitations. The review concludes that the accumulated evidence positions microbial-based biological inputs as an increasingly indispensable, rather than merely supplementary, component of sustainable horticulture, with direct implications for climate-adaptive agricultural policy and food security.