Nanopolysaccharides in agriculture. Advances, applications, and future prospects: a review

Nanopolysaccharides (NPSs) constitute a rapidly advancing class of biodegradable and biocompatible nanomaterials with strong potential to support sustainable, climate-resilient agriculture. NPSs exhibit high surface area, tunable surface chemistry, and enhanced interactions with biological interfaces, enabling multifunctional roles across soil–plant–microbe systems. This review provides a function-guided synthesis of recent advances in NPS-based agricultural applications, structured around ten interconnected functional domains. These include: (i) structural classes of NPSs and their surface-chemistry-driven functionality; (ii) soil improvement and moisture regulation; (iii) slow and controlled release of mineral fertilizers (e.g., NPK, urea, ammonium and phosphate salts); (iv) foliar delivery for nutrient uptake and stress mitigation; (v) direct antibacterial and antifungal activity against major phytopathogens; (vi) antiviral strategies, including nano-enabled RNA interference delivery; (vii) nano-loading and targeted delivery of agrochemicals, micronutrients, and botanical actives; (viii) induction of plant defense and immune priming; and (ix) encapsulation and nanocoating of agriculturally important microbial inoculants to enhance survival, controlled release, and field performance; and (x) seed nanopriming for improved germination, stress resilience, and early vigor. Emphasis is placed on structure–function relationships linking nanoparticle size, surface charge, crystallinity, functional group density, and cross-linking chemistry to agronomic outcomes, providing a framework for rational design of next-generation NPS-based agricultural formulations.