Exploring biocontrol strategies for Phytopathogens using plant growth-promoting rhizobacteria-derived enzymes: A review of current advances and future directions.

The growing demand for sustainable agriculture imposes innovative biocontrol strategies to mitigate phytopathogen threats while reducing dependence on chemical pesticides. This review explores the current knowledge on enzyme-based biocontrol, focusing on hydrolytic enzymes (e.g., chitinases, pectinases, cellulases, proteases, and β-glucanases) produced by plant-growth-promoting-rhizobacteria (PGPRs) and their dual roles in direct pathogen suppression and plant immunity elicitation. We systematically evaluate their mechanisms, from cell wall degradation to induced systemic resistance (ISR), and highlight synergistic interactions that enhance efficacy under field conditions. Despite promising laboratory and greenhouse results, commercial implementation faces challenges: high production costs, environmental instability, and formulation limitations. We critically analyze advances in immobilization techniques (e.g., nanoencapsulation, biochar carriers) and low-cost production using agro-industrial wastes to improve scalability. Furthermore, we discuss the market potential of enzyme-based biocontrol agents, which is projected to grow at a Compound Annual Growth Rate (CAGR) of 16.4 %, and identify gaps in rhizosphere compatibility and regulatory frameworks. By integrating metagenomic insights and molecular engineering, this review proposes a roadmap for optimizing enzyme cocktails tailored to specific crops and pathogens. Our findings highlight the transformative potential of enzyme-driven biocontrol in achieving sustainable crop protection, influencing interdisciplinary collaboration to bridge lab-to-field disparities and meet global food security challenges.