Engineering the plant holobiont for enhanced abiotic stress resilience: current insights and future directions

Climate change has intensified abiotic stresses such as drought, heat, and salinity, posing major threats to agricultural productivity and global food security. Conventional strategies to improve crop tolerance often face limitations in efficiency, sustainability, and environmental adaptability, underscoring the need for innovative approaches. This review focuses on the plant holobiont, which views plants and their associated microbiomes as an integrated functional unit in governing stress adaptation. Abiotic stress can disrupt plant-associated microbial communities, leading to dysbiosis and reduced holobiont resilience. Beneficial microorganisms, including plant growth-promoting rhizobacteria, endophytes, and arbuscular mycorrhizal fungi, can enhance stress tolerance by improving nutrient acquisition, regulating phytohormone signaling, strengthening antioxidant defenses, maintaining osmotic balance, and modulating stress-responsive gene expression. Emerging evidence suggests that these interactions contribute to the establishment of holobiont stress adaptation through biochemical signaling, microenvironmental modification, and epigenetic regulation, enabling plants to respond more effectively to recurrent stress. Advances in microbiome engineering, particularly through the development of synthetic microbial communities (SynComs), offer promising opportunities to restore microbial functions and enhance crop resilience under changing climatic conditions. The integration of multi-omics technologies, artificial intelligence, and precision agriculture is expected to accelerate the development of microbiome-based solutions for sustainable crop production. Collectively, microbiome engineering represents a promising, environmentally sustainable strategy to enhance the holobiont's adaptive resilience and improve long-term plant performance under abiotic stress.