Effects of native arbuscular mycorrhizal and phosphate-solubilizing fungi on coffee plants

Abstract

The effects of the interaction between arbuscular mycorrhizal and phosphate-solubilizing (P-solubilizing) fungi on phosphorous availability, acid phosphatase activity, and the growth and development of coffee plants (Coffea arabica L.) var. garnica were evaluated. The experiment was performed under controlled conditions and was based on a randomized factorial design with two factors. Coffee plants were inoculated with a consortium of arbuscular mycorrhizal fungi (CAMF), two strains of P-solubilizing fungi (PSF) (Aspergillus niger [An] and Penicillium brevicompactum [Pb]), the possible combinations of the latter fungi, and an uninoculated control. After 8 months, the results demonstrated the effectiveness of mycorrhizal and P-solubilizing fungal inoculations in increasing available soil phosphorous. The greatest concentration of available soil phosphorous was detected in the consortium of P-solubilizing fungi (CPSF) treatment at 3.8 mg/kg. The total foliar phosphorous concentration of plants was higher in the CAMF, An + CAMF, CPSF + CAMF, Pb + CAMF, and CPSF treatments in comparison to the control treatment. The growth of coffee plants was also favored by the consortium treatments (P-solubilizing fungi and arbuscular mycorrhizal fungi). The acid phosphatase activity in the rhizosphere significantly increased under the CPSF treatment and also increased in the roots of coffee plants under the An, An + CAMF, and CPSF + CAMF treatments. Given the importance of fungal groups for processes of phosphorous transformation and absorption in coffee plants, it is imperative to continue the search for native fungal strains with high potential for use as biofertilizers.