Phase Separation-Induced Coating to Optimize the Seed Microenvironment for Enhanced Germination and Mitigation of Fungus/Freeze Damage

Germination and seedling growth are generally threatened by various pathogens and adverse conditions. The emergence of seed coating technology has effectively improved the seed germination quality and crop yield. However, limited coating systems cannot meet the complex requirements of the seeds. Herein, a multifunctional gel-like coacervate is constructed by biosurfactant sodium deoxycholate with biogenic polyamines, wetting the entire seed surface during phase separation rapidly and forming a transparent, water-repellent coating with micrometer thickness on the seed surface in an extremely short immersion time. In parallel, the coacervate coating effectively encapsulates phytohormones to promote seed germination and mitigate biotic/abiotic stressors. Notably, this kind of coating system shows significant antifungal activity and frost resistance, allowing seeds to resist broad-spectrum pathogens without fungicides and low temperatures. Moreover, the compositions of coacervate are of biological origin, presenting low toxicity to aqueous organisms and soil microflora. Thus, this approach provides a comprehensive and sustainable strategy to support seed germination and growth as a protective screen.