Characterisation and dynamics of the fungal communities of Avena fatua and Echinochloa crus‐galli seeds in soil seed bank

Abstract

Survival in the soil seed bank is critical to a weed maintaining populations in arable lands. The role of the seed‐borne fungi in seed decay or survival needs to be determined to find solutions for reducing the weed seed banks in environmentally friendly ways. In this study, changes of the fungal microbiome after seed burial were determined in two economically important weed species, wild oat and barnyard grass. Seeds collected in different populations were buried in two sites and exhumed at intervals over the period of 1.5 years to test the seed fate. Epiphytic and endophytic fungal microbiota of seeds was characterised using both culture‐based approach and NGS of ITS1 region. The proportion of visually intact seeds and decayed seeds was different between the two burial sites. The observed species richness of the isolated epiphytic fungi was higher in the fresh compared to the buried seeds. Fungal taxa determined by NGS amplicon sequencing only partly coincided with the isolated fungi, revealing higher diversity in buried seeds. The dynamic of taxonomic structure of the fungal community was less pronounced in wild oat seeds compared to the barnyard grass seeds, where both endophytic and epiphytic communities were significantly different in the buried seeds and differed between the burial sites. It can be concluded that the epiphytic fungal communities change after seed burial in both plant species, while endophytic communities are more stable in the intact seeds and changes of the fungal community in the seed endosphere may be associated with seed decay.