Mineral phosphorus fertilization modulates interactions between maize, rhizosphere yeasts and arbuscular mycorrhizal fungi

Yeasts are abundant and diverse in rhizosphere soil, but information about their importance in agroecosystems is limited. Here we examined maize plant growth response to inoculation with the native maize rhizosphere yeasts Cryptococcus flavus and Candida railenensis in non-mycorrhizal and mycorrhizal maize without and with mineral P fertilization as KH2PO4. Maize plant growth promotion and suppression was observed after inoculation with a native community of arbuscular mycorrhizal (AM) fungi with and without mineral P fertilization, respectively. Inoculation with Cr. flavus reduced shoot biomass of maize plants irrespective of the mycorrhizal status, but only without P fertilization. AM fungal root colonization was increased by C. railenensis without P fertilization, but was reduced by Cr. flavus in combination with mineral P fertilization. In conclusion, our results show that mineral P fertilization strongly modulates interactions between maize, rhizosphere yeasts and AM fungi, which are important to take into account when integrating such root associated microorganisms as biofertilizers in agroecosystems.
This study was supported with the grant 179319 from Consejo Nacional de Ciencia y Tecnología (CONACYT). Marcela Sarabia was supported with the Ph.D. fellowship 239182 also from CONACYT.