Effect of inoculation with soil yeasts on mycorrhizal symbiosis of maize

SummaryInteractions between arbuscular mycorrhizal fungi (AMF) and soil yeasts were studied in a pot experiment conducted in substrate from a spoil bank. Maize was inoculated with AMF (Glomus intraradices BEG140 and Glomus mosseae BEG95), three soil yeast species (Candida sake, Cryptococcus aerius and Williopsis californica) and combinations of these microorganisms. In plants inoculated with yeasts alone, only Candida sake increased maize growth while the dual inoculation of plants with Glomus intraradices and any of the three yeasts showed positive effects on shoot biomass. Presence of soil yeasts did not significantly affect mycorrhizal colonisation of maize roots but negatively affected the length of the AMF extraradical mycelium (ERM). Soil yeast numbers were significantly influenced by AMF with both positive and negative effects observed. It can be concluded that dual inoculation of maize with yeasts and AMF resulted in increased shoot biomass depending on the combination of yeast species and AMF isolate.