Title : Endophytic capabilities of rhizoctonia like fungi in Zea mays
Abstract:
Rhizoctonia-like fungi have been recognized as key symbionts in orchid mycorrhizal (OM) associations for over a century. More than three decades ago, researchers discovered that these fungi also colonize the roots of various non-orchid plants. Today, the ability of Rhizoctonia-like fungi, particularly from the order Sebacinales, to establish all known mycorrhizal types (except arbuscular mycorrhiza) and endophytic associations is well documented. However, endophytic interactions involving other rhizoctonias that typically form OM with green orchids remain poorly studied, partly due to the lack of a reliable method for inducing such associations. This study aimed to assess the influence of mineral nutrient availability and host plant decapitation—triggering a shift from biotrophic to saprotrophic nutrition—on the colonization of maize (Zea mays) roots by rhizoctonias. We found that inoculating maize with fungi cultivated on zeolite saturated with either ½ MS medium or oat-flake medium effectively initiated endophytic associations. While nutrient availability had no statistically significant effect on fungal colonization, a striking increase in root colonization was observed when the fungi transitioned from biotrophy (~20% of root length) to saprotrophy (~98%). These findings highlight the potential ecological role of rhizoctonias in nutrient transfer from decaying plant biomass to actively growing plants, suggesting their broader significance beyond orchid mycorrhiza. The research was funded by the Ministry of Agriculture of the Czech Republic (MZE-RO1123, MZE-RO1623, QL24010008), IGA_PrF_2025_001 and MUNI/A/1799/2024.
