title: Phytophthora infestans Argonaute 1 binds microRNA and small RNAs from effector genes and transposable elements.
abstract: Phytophthora spp. encode large sets of effector proteins and distinct populations of small RNAs (sRNAs). Recent evidence has suggested that pathogen-derived sRNAs can modulate the expression of plant defense genes. Here, we studied the sRNA classes and functions associated with Phytophthora infestans Argonaute (Ago) proteins. sRNAs were co-immunoprecipitated with three PiAgo proteins and deep sequenced. Twenty- to twenty-two-nucleotide (nt) sRNAs were identified as the main interaction partners of PiAgo1 and high enrichment of 24-26-nt sRNAs was seen in the PiAgo4-bound sample. The frequencies and sizes of transposable element (TE)-derived sRNAs in the different PiAgo libraries suggested diversified roles of the PiAgo proteins in the control of different TE classes. We further provide evidence for the involvement of PiAgo1 in the P. infestans microRNA (miRNA) pathway. Protein-coding genes are probably regulated by the shared action of PiAgo1 and PiAgo5, as demonstrated by analysis of differential expression. An abundance of sRNAs from genes encoding host cell death-inducing Crinkler (CRN) effectors was bound to PiAgo1, implicating this protein in the regulation of the expanded CRN gene family. The data suggest that PiAgo1 plays an essential role in gene regulation and that at least two RNA silencing pathways regulate TEs in the plant-pathogenic oomycete P. infestans.
authors.affiliation: Department of Plant Biology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Linnéan Center for Plant Biology, PO Box 7080, SE-75007, Uppsala, Sweden.
authors.forename: Anna K M
authors.initials: AK
authors.lastname: Åsman
authors.affiliation: Department of Plant Biology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Linnéan Center for Plant Biology, PO Box 7080, SE-75007, Uppsala, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Fogelqvist
authors.affiliation: Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Resistance Biology Unit, PO Box 102, SE-23053, Alnarp, Sweden.
authors.forename: Ramesh R
authors.initials: RR
authors.lastname: Vetukuri
authors.affiliation: Department of Plant Biology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Linnéan Center for Plant Biology, PO Box 7080, SE-75007, Uppsala, Sweden.
authors.forename: Christina
authors.initials: C
authors.lastname: Dixelius
mesh_terms: D060565:Argonaute Proteins / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D004251:DNA Transposable Elements / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D035683:MicroRNAs / Q000378:metabolism*; D009711:Nucleotides / Q000378:metabolism; D009868:Oomycetes / Q000378:metabolism; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D055750:Phytophthora infestans / Q000235:genetics* / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology; D011544:Pseudogenes / Q000235:genetics; D015203:Reproducibility of Results
chemical_list: D060565:Argonaute Proteins; D004251:DNA Transposable Elements; D035683:MicroRNAs; D009711:Nucleotides; D049452:Green Fluorescent Proteins
keywords: Argonaute (Ago); Crinkler (CRN); Phytophthora infestans; effector; microRNA (miRNA); transposon