Epiphytic and Endophytic Fungi Colonizing Seeds of Two Poaceae Weed Species and Fusarium spp. Seed Degradation Potential In Vitro

Fungi colonizing the surface and endosphere of two widespread Poaceae weed species, Avena fatua and Echinochloa crus-galli, were isolated to compare the taxonomic composition between the plant species, location, and year of the seed collection. The seed-degrading potential of Fusarium isolated from the seeds was tested by inoculating seeds of E. crus-galli with spore suspension. Molecular identification of epiphytic and endophytic fungal genera was performed by sequencing the ITS region of rDNA. Endophytes comprised of significantly lower fungal richness compared to epiphytes. A significant taxonomic overlap was observed between the endosphere and seed surface. The most abundant genera were Alternaria, Fusarium, Cladosporium, and Sarocladium. Analysis of similarities and hierarchical clustering showed that microbial communities were more dissimilar between the two plant species than between the years. Fusarium isolates with a high potential to infect and degrade E. crus-galli seeds in laboratory conditions belong to F. sporotrichioides and F. culmorum.

Automated summary

This study isolated fungi from the surface and endosphere of two widespread Poaceae weed species, Avena fatua and Echinochloa crus-galli, to compare their taxonomic composition. The seed-degrading potential of Fusarium isolated from the seeds of E. crus-galli was tested. Molecular identification of epiphytic and endophytic fungal genera was performed. Endophytes had significantly lower fungal richness compared to epiphytes. There was a significant taxonomic overlap between the endosphere and seed surface, with Alternaria, Fusarium, Cladosporium, and Sarocladium being the most abundant genera. Microbial communities showed greater dissimilarity between the two plant species than between the years. Fusarium isolates F. sporotrichioides and F. culmorum demonstrated high potential to infect and degrade E. crus-galli seeds under laboratory conditions.