Mobilisation of unavailable phosphorus and improvement of pepper P absorption, fruit yield and quality by the wood rot-fungus

Abstract

Aims P-mobilising microbes may effectively increase soil P availability. These experiments investigated soil P mobilisation and pepper (Capsicum annuum L.) P uptake in response to the wood-rot fungus Fomitopsis palustris CQ2018. Methods F. palustris CQ2018 was incubated in liquid media and soil to study P mobilisation, and pepper plants with fungal inoculation were grown in a greenhouse experiment to observe the agronomic performances. Key results F. palustris CQ2018 secreted protons, organic acids, and phosphatase to convert AlPO4, Ca3(PO4)2, FePO4 and lecithin into soluble P in liquid culture and increased P availability in three soils with pH 5.53, 7.36 and 8.67. It grew in the roots or on the root surfaces, stimulated root growth, increased dehydrogenase activity in the roots, and solubilised water-insoluble P. Soil inoculated with F. palustris CQ2018 exhibited higher Olsen P and phosphatase activity than uninoculated soil, and there was a positive linear correlation between Olsen P and phosphatase activity (r = 0.788). F. palustris CQ2018 increased pepper P uptake and fruit yield in both unfertilised and fertilised soils even under the condition of reduced fertilisers. Fruit quality was also improved by the increase in P, potassium, and vitamin C but decrease in nitrate. Conclusions F. palustris CQ2018 can mobilise soil P and improve plant P uptake and fruit yield and quality in pepper. Implications F. palustris CQ2018 may be developed into a new, effective, and environmentally friendly biofertiliser. Its effect on different plants in various soils needs further study.