Phytopathogenic protist Albugo candida secretes cationic intrinsically disordered peptides with antimicrobial activity against plant-associated bacteria

ABSTRACT: Positive and negative ecological interactions shape the dynamics and composition of natural microbial communities. The mechanisms behind microbe-microbe interactions, particularly those protein-based, are not well understood and only a small percentage of such interactions has been studied. We hypothesize that secreted proteins are a powerful and highly specific toolset to shape and defend a favorable plant niche. Here, we have studied Albugo candida, an obligate plant parasite from the protist Oomycota phylum, for its potential to inhibit and promote the growth of bacteria through secretion of proteins into the apoplast. Amplicon sequencing and network analysis of Albugo-infected and uninfected samples revealed an abundance of negative correlations between Albugo and other phyllosphere microbes. Analysis of the secreted proteome of Albugo candida combined with machine-learning predictors enabled the selection of candidates for heterologous expression and study of their inhibitory activity in vitro. We found that three of the candidate proteins showed a selective antimicrobial activity on several gram-positive bacterial strains isolated from Arabidopsis thaliana. We could ascribe the antibacterial activity of the candidates to their intrinsically disordered regions and positively correlate it with their net charge. This is the first report of protist proteins that have an antimicrobial activity under apoplastic conditions and therefore are potential biocontrol tools for a targeted manipulation of the microbiome.

INSTRUMENT(S): Orbitrap Exploris 480, Q Exactive HF

ORGANISM(S): Albugo Candida Acnc2 Arabidopsis Thaliana (mouse-ear Cress) Albugo Laibachii Nc14

TISSUE(S): Leaf

SUBMITTER: Daniel Gomez Perez  

LAB HEAD: Eric Kemen

PROVIDER: PXD031981 | Pride | 2023-05-31

REPOSITORIES: Pride