The Potential of Rhizoctonia-Like Fungi for the Biological Protection of Cereals against Fungal Pathogens.

Dominik Bleša,Romana Sedmíková,Pavel Matušinský,Milan Baláž

doi:10.3390/plants10020349

Abstract

The use of biological control is becoming a common practice in plant production. One overlooked group of organisms potentially suitable for biological control are Rhizoctonia-like (Rh-like) fungi. Some of them are capable of forming endophytic associations with a large group of higher plants as well as mycorrhizal symbioses. Various benefits of endophytic associations were proved, including amelioration of devastating effects of pathogens such as Fusarium culmorum. The advantage of Rh-like endophytes over strictly biotrophic mycorrhizal organisms is the possibility of their cultivation on organic substrates, which makes their use more suitable for production. We focused on abilities of five Rh-like fungi isolated from orchid mycorrhizas, endophytic fungi Serendipita indica, Microdochium bolleyi and pathogenic Ceratobasidium cereale to inhibit the growth of pathogenic F. culmorum or Pyrenophora teres in vitro. We also analysed their suppressive effect on wheat infection by F. culmorum in a growth chamber, as well as an effect on barley under field conditions. Some of the Rh-like fungi affected the growth of plant pathogens in vitro, then the interaction with plants was tested. Beneficial effect was especially noted in the pot experiments, where wheat plants were negatively influenced by F. culmorum. Inoculation with S. indica caused higher dry shoot biomass in comparison to plants treated with fungicide. Prospective for future work are the effects of these endophytes on plant signalling pathways, factors affecting the level of colonization and surviving of infectious particles.

Highlights

Endophytic capabilities of fungi forming orchid mycorrhizas were observed many times in different plant families [1,2,3]
The degradation of P. teres colonies Plants 2021, 10, x FOR PEER REVIEWmanifested as darkening of the mycelium was initiated by the presence of three Rh4-olifk1e6 fungi, Ceratobasidium sp. isolate 2015/1, C. cereale, and Tulasnella sp. isolate 2016/11
We revealed that the results obtained in vitro—the antagonistic effect of M. bolleyi or C. cereale against F. culmorum, do not correspond to the results of the pot experiments, in which M. bolleyi did not affect and C. cereale reduced the values of parameters tested

Summary

Introduction

Endophytic capabilities of fungi forming orchid mycorrhizas were observed many times in different plant families [1,2,3] The majority of these orchid symbionts belongs into a wide group of fungi mostly from phylum Basidiomycota, few members being from Ascomycota [4]. The morphological definition of Rh-like fungi includes monilioid cells, unimpaired parenthosomes getting into doliporus septa and right-angle branching of hyphae [4,5,6]. The former methods of their identification were based mainly on morphological parameters, while recent identification of Rh-like fungi is based on the molecular methodology as the sequencing of, e.g., ITS regions of rDNA [7]. The fungi from Rh-like group are cosmopolitans mostly with saprotrophic abilities [4], but the life strategy and other ecological aspects of these endophytes are not well-known [3]

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