Exploring synergistic interactions between arbuscular mycorrhizal fungi and Silwet adjuvants to combat drought stress in crops.

Drought is a major jeopardy to global food security. Soil adjuvants such as organosilicone surfactants are a possible tool to increase crop drought tolerance. In this study, the effect of the interaction between organosilicone surfactants and arbuscular mycorrhizal fungi (AMF) on crop drought tolerance was investigated. An in vitro ecotoxicology study revealed that exposure to organosilicone surfactants did not affect germination of AMF spores but reduce length of hyphae produced by spores in the asymbiosis growth phase. The organosilicone surfactants significantly improved water retention of hydrophobic soils and impacted nutrient accumulation and distribution in both Zea mays L. and Vicia faba L.. There was an antagonistic relationship between phosphorus and calcium uptake and silicon uptake in Z. mays, while distribution of potassium and silicon was altered in the presence of the surfactant, favouring aboveground accumulation. Nitrogen accumulation in Z. mays facilitated by AMF was inhibited by the surfactants. Increased concentration of the osmolyte proline in V. faba indicated heightened drought stress in the presence of the surfactant. Both soil water retention benefits and ecotoxicological impacts of the
surfactant were greater when the surfactant was present at a low concentration compared to the higher concentrations tested. These findings suggest that while organosilicone surfactants enhance soil water retention, their application alongside AMF biofertilizer may adversely affect arbuscular mycorrhizal symbiosis, plant nutrient uptake, and stress response mechanisms, potentially exacerbating drought
stress by compromising the symbiotic relationship between plants and AMF and impeding their ability to efficiently cope with water scarcity and environmental stressors. These results demonstrate the importance of careful consideration when utilizing organosilicone surfactants in agricultural systems, highlighting the intricate balance between soil water management, symbiotic relationships, and nutrient dynamics crucial for sustainable crop resilience in the face of escalating climate challenges.