High Diversity Revealed in Leaf‐Associated Protists (Rhizaria: Cercozoa) of Brassicaceae

Abstract

The largest biological surface on earth is formed by plant leaves. These leaf surfaces are colonized by a specialized suite of leaf‐inhabiting microorganisms, recently termed “phyllosphere microbiome”. Microbial prey, however, attract microbial predators. Protists in particular have been shown to structure bacterial communities on plant surfaces, but virtually nothing is known about the community composition of protists on leaves. Using newly designed specific primers targeting the 18S rDNA gene of Cercozoa, we investigated the species richness of this common protist group on leaves of four Brassicaceae species from two different locations in a cloning‐based approach. The generated sequences revealed a broad diversity of leaf‐associated Cercozoa, mostly bacterial feeders, but also including known plant pathogens and a taxon of potential endophytes that were recently described as algal predators in freshwater systems. This initial study shows that protists must be regarded as an integral part of the microbial diversity in the phyllosphere of plants.

Diversity of Cercomonad Species in the Phyllosphere and Rhizosphere of Different Plant Species with a Description of Neocercomonas epiphylla (Cercozoa, Rhizaria) a Leaf‐Associated Protist

“…Studies confirm the regular presence of ciliates, amoebae and flagellates on plant leaves (Bamforth ; Mueller and Mueller ; Ploch et al. ; Vaerewijck et al. , ).…”

“…Ploch et al. () reported a high diversity of cercozoan taxa in the phyllosphere of Brassicaceae. Cercomonadida appear to be also enriched in the rhizosphere of plants compared to bulk soil (Turner et al.…”

Insights into protist diversity and biogeography in intertidal sediments sampled across a range of spatial scales

“…Cercozoa is a large group of protists, encompassing high morphological, functional, and ecological diversity. It is a well‐studied lineage adapted to terrestrial, marine benthic, and anaerobic habitats (Bass et al ; Ploch et al ), but its environmental diversity remains underexplored (Fiore‐Donno et al ), especially in the intertidal zone. This study provides the first detailed insights into the diversity and biogeography of Cercozoa in intertidal sandy ecosystems.…”

Xanthomonas citri T6SS mediates resistance to Dictyostelium predation and is regulated by an ECF σ factor and cognate Ser/Thr kinase

“…Plant leaves represent the largest biological surface on the biosphere (Penuelas and Terradas, 2014) and bacteria are the most abundant organisms of this habitat (Lindow and Brandl, 2003). Bacteria are a rich food source for protists on the soil and plant surfaces, whose predatory behaviour is responsible for shaping the composition of the local microbiome (Bonkowski, 2004;Rosenberg et al, 2009;Ploch et al, 2016).…”