Molecular characterization and endophytic nature of the root-associated fungus Meliniomyces variabilis (LtVB3)

Abstract

The root-associated fungus LtVB3 was formerly reported as a potential, new biocontrol agent of Verticillium yellows of Chinese cabbage and Fusarium wilt of tomato. According to molecular phylogenetic analysis of the ITS 1-5.8S rDNA-ITS 2 gene regions and morphological characteristics, LtVB3 is here identified as Meliniomyces variabilis, a recently described species [formerly called ''Variable White Taxon'' (VWT)] in a new genus erected to accommodate sterile fungi with phylogenetic affinities to Rhizoscyphus ericae, an ericoid mycorrhizal fungus. In vitro inoculation experiments showed that LtVB3 colonized the roots of torch azalea and eucalyptus; however, growth was enhanced only in azalea but not in eucalyptus. Hyphae of M. variabilis formed intracellular structures typical of ericoid mycorrhizas in epidermal cells of azalea roots but did not produce any typical ectomycorrhizal structures with or within root cells of either host. In LtVB3-treated eucalyptus roots, some cells in the epidermal and cortical layers had wall appositions and thickenings, which appeared to restrict fungal growth.

New insights into the mycorrhizal Rhizoscyphus ericae aggregate: spatial structure and co‐colonization of ectomycorrhizal and ericoid roots

“…It may be that M. variabilis is an endophyte in ectomycorrhizas formed by other fungi. This would be compatible with its ability to function as an ERM fungus, and support recent reports of endophytic behaviour in several ECM and ERM host plants (Ohtaka & Narisawa, 2008; Vohnik et al. , 2007a,b) or DNA amplification from ectomycorrhizas formed by other fungal species (Tedersoo et al.…”

Reciprocal carbon and nitrogen transfer between an ericaceous dwarf shrub and fungi isolated from Piceirhiza bicolorata ectomycorrhizas

“…The nature of the interaction between our M. variabilis isolates and the pine roots from which they were isolated is unknown. Ohtaka & Narisawa (2008) showed that a M. variabilis strain isolated from barley roots could colonize both Azalea (ERM) and Eucalyptus (ECM) roots. However, the fungus enhanced shoot growth only in the case of Azalea .…”

Rhizosphere mycobiome diversity in four declining Mediterranean tree species

“…Humicola is a genus of endophytic fungi of great biotechnological interest in recent years, mainly related to halophytic plants and production of chemical compounds for industrial use (Hosseyni-Moghaddam et al, 2020). Meliniomyces is a genus of endophytic fungi and ericoid mycorrhiza (Ohtaka and Narisawa, 2008;Vohnik et al, 2013). Pleorotus is a genus of widely known edible 10.3389/ffgc.2023.1215701…”