Broad-scale phenotyping in Arabidopsis reveals varied involvement of RNA interference across diverse plant-microbe interactions.

RNA interference (RNAi) is a crucial mechanism in immunity against infectious microbes through the action of DICER-LIKE (DCL) and ARGONAUTE (AGO) proteins. In the case of the taxonomically diverse fungal pathogen and the oomycete , plant DCL and AGO proteins have proven roles as negative regulators of immunity, suggesting functional specialization of these proteins. To address this aspect in a broader taxonomic context, we characterized the colonization pattern of an informative set of and loss-of-function mutants in upon infection with a panel of pathogenic microbes with different lifestyles, and a fungal mutualist.

A fungal RNA-dependent RNA polymerase is a novel player in plant infection and cross-kingdom RNA interference.

Small RNAs act as fungal pathogen effectors that silence host target genes to promote infection, a virulence mechanism termed cross-kingdom RNA interference (RNAi). The essential pathogen factors of cross-kingdom small RNA production are largely unknown. We here characterized the RNA-dependent RNA polymerase (RDR)1 in the fungal plant pathogen Botrytis cinerea that is required for pathogenicity and cross-kingdom RNAi.

Plant ARGONAUTE Protein Immunopurification for Pathogen Cross Kingdom Small RNA Analysis.

Over the last decade, it has been noticed that microbial pathogens and pests deliver small RNA (sRNA) effectors into their host plants to manipulate plant physiology and immunity for infection, known as cross kingdom RNA interference. In this process, fungal and oomycete parasite sRNAs hijack the plant ARGONAUTE (AGO)/RNA-induced silencing complex to post-transcriptionally silence host target genes. We hereby describe the methodological details of how we recovered cross kingdom sRNA effectors of the oomycete pathogen during infection of its host plant .

An Arabidopsis downy mildew non-RxLR effector suppresses induced plant cell death to promote biotroph infection.

Our understanding of obligate biotrophic pathogens is limited by lack of knowledge concerning the molecular function of virulence factors. We established Arabidopsis host-induced gene silencing (HIGS) to explore gene functions of Hyaloperonospora arabidopsidis, including CYSTEINE-RICH PROTEIN (HaCR)1, a potential secreted effector gene of this obligate biotrophic pathogen. HaCR1 HIGS resulted in H.