Feremycorrhizal Fungus Austroboletus occidentalis Improves Growth and Nutrition of Diverse Crop and Pasture Species

Abstract Feremycorrhiza (FM) is a beneficial symbiosis between the Australian native fungus Austroboletus occidentalis and diverse plant species, including eucalypts, arbuscular mycorrhizal (AM) crops, and non-AM crops such as canola. This study aimed to investigate the generalist nature of the FM fungus across multiple host plants, and its effects on plant-available soil phosphorus (P) and plant P uptake efficiency (PUpE). The effects of A. occidentalis on plant growth, shoot nutrient uptake, soil P availability, and PUpE in 14 crop and pasture species including cereals, forage grasses, legumes, and oilseeds were investigated under P-deficient conditions, using low-P soils (Colwell P = 4–5 mg kg − 1 ) supplemented with a minimal P dose (2 mg kg − 1 ). Plants were harvested after 6 weeks of growth. Inoculated plants of all species had significantly increased shoot and root biomass, compared with the non-inoculated controls. Most inoculated crop and pasture species also exhibited increased shoot contents of nutrients, including P, nitrogen, potassium, and several micronutrients. Plant-available P in soil was significantly higher ( p < 0.05) in the inoculated treatments compared with the non-inoculated controls across all plant species. PUpE was also enhanced in most inoculated species, with the highest gains in wheat (by 122%) and maize (by 65%) relative to the control. Austroboletus occidentalis formed effective symbiosis with a wide range of crops and pastures, highlighting its role as a generalist symbiont. By enhancing soil-available P, plant nutrient uptake and growth, the FM symbiosis presents a novel approach for sustainable P management in cropping and pasture systems. Graphical Abstract