Fungal endophytes from wild Solanum torvum seeds: diversity and antagonism against plant pathogens

This study investigates the endophytic microbial communities from the seeds of two Solanum species, selected for their contrasting resistance to the plant pathogen Meloidogyne incognita (Kofold & White) Chitwood: Solanum torvum Sw., which is highly resistant, and Solanum melongena L., which is highly susceptible. Aseptic extractions from individual seeds, followed by molecular analysis, revealed a variety of culturable microbial strains. Our results focused on the differential culturable microorganisms associated with two genotypes. Notably, significant differences were observed in the fungal communities, with the identification of the fungus Lecanicillium aphanocladii and the yeast Papiliotrema flavescens (formerly Cryptococcus flavescens) exclusively in S. torvum. This represents the first report of these fungal species associated with Solanum seeds. We characterized the micro-morphology, growth patterns, and molecular phylogenetic relationships of L. aphanocladii, based on two independent genetic loci. In vitro bioassays demonstrated the biocontrol potential of P. flavescens which inhibited Botrytis cinerea mycelial growth up to 60% and reduced the viability of M. incognita juveniles by 35%. Similarly, L. aphanocladii exhibited antagonistic activity against B. cinerea and was capable of capturing and digesting the plant-parasitic nematode M. incognita and the plant-associated Bursaphelenchus eremus Ruhm. These findings suggest that the unique endophytic microorganisms isolated from S. torvum may play a role in its natural resistance and have potential as biological control agents, supporting their use in integrated pest and disease management strategies.