Fungivorous protists in the rhizosphere ofArabidopsis thaliana– Diversity, functions, and publicly available cultures for experimental exploration

Abstract

AbstractIn the context of the soil food web, the transfer of plant-fixed energy and carbon to higher trophic levels has traditionally been attributed to two main energy channels: the fungal energy channel and the bacterial energy channel. Historically, protists were overlooked in the fungal energy channel, which was believed to be controlled by fungivorous microarthropods and nematodes. In this study, we investigated fungivorous protists in the rhizosphere ofArabidopsis thaliana. Our findings revealed a notable abundance and diversity of protists that have developed specialized strategies to overcome the protective cell wall of fungi. Among the identified species were two Vampyrellida (Rhizaria) species, namelyTheratromyxa weberiandPlatyreta germanica, as well as one Arcellinida (Amoebozoa) species, calledCryptodifflugia oviformis. WhileT. weberitypically consumed entire fungal cells, the other two species perforated fungal cell walls and extracted the cellular contents. We elucidate the feeding strategies and dietary ranges of the amoebae, highlighting the non-uniform nature of fungivory in protists, as different taxa have evolved distinct approaches to access fungi as a food source. Moreover, we provide publicly available cultures of these protists to facilitate further experimental investigations within the research community.