title: MicroRNA400-guided cleavage of Pentatricopeptide repeat protein mRNAs Renders Arabidopsis thaliana more susceptible to pathogenic bacteria and fungi.
abstract: Although a large number of microRNAs (miRNAs) have been identified in different plant species, the functional roles and targets of the majority of miRNAs have not yet been determined. Here, Arabidopsis thaliana miRNA400 (miR400) was investigated for its functional role in the defense response to diverse pathogens. Transgenic Arabidopsis plants that overexpress MIR400 (35S::MIR400) displayed much more severe disease symptoms than the wild-type plants when infected with the bacterium Pseudomonas syringae pv. tomato DC3000 or the fungus Botrytis cinerea. MiR400 guided the cleavage of two genes (At1g06580 and At1g62720) encoding pentatricopeptide repeat (PPR) proteins. To confirm further that the miR400-mediated defense response was due to the cleavage of PPR mRNAs, loss-of-function mutant and artificial miRNA-mediated knockdown mutants of PPR were generated, and their disease responses were analyzed upon pathogen challenge. Similar to the 35S::MIR400 plants, the ppr mutants displayed much more severe disease symptoms than the wild-type plants when challenged with the pathogens, indicating that miR400 affects the defense response by cleaving PPR mRNAs. Expression of miR400 was down-regulated, whereas the PPR1 and PPR2 transcripts increased upon pathogen challenge. Collectively, the present study reveals that miR400-mediated dysfunction of PPR proteins renders Arabidopsis more susceptible to pathogenic bacteria and fungi, which emphasizes the importance of PPR proteins in plant defense against diverse pathogens.
authors.affiliation: Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea These authors contributed equally to this work.
authors.forename: Young Ju
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea These authors contributed equally to this work.
authors.forename: Hwa Jung
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea.
authors.forename: Kyung Jin
authors.initials: KJ
authors.lastname: Kwak
authors.affiliation: Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea.
authors.forename: Kwanuk
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Molecular Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea.
authors.forename: Suk Whan
authors.initials: SW
authors.lastname: Hong
authors.affiliation: Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea hskang@jnu.ac.kr.
authors.forename: Hunseung
authors.initials: H
authors.lastname: Kang
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D020171:Botrytis / Q000502:physiology; D004198:Disease Susceptibility; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D018525:Germination; D006358:Hot Temperature; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D010935:Plant Diseases / Q000276:immunology*; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000502:physiology; D030821:Plants, Genetically Modified; D044224:Pseudomonas syringae / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D036226:Seedlings / Q000235:genetics / Q000276:immunology / Q000502:physiology; D012639:Seeds / Q000235:genetics / Q000276:immunology / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; C000598020:At1G06580 protein, Arabidopsis; D035683:MicroRNAs; D024101:Mitochondrial Proteins; C568889:NG1 protein, Arabidopsis; D012333:RNA, Messenger; D018749:RNA, Plant; C000598019:microRNA400, Arabidopsis; C538752:pentatricopeptide repeat protein, Arabidopsis
keywords: Arabidopsis thaliana; Defense; MiR400; MicroRNA; Pathogen; Pentatricopeptide repeat protein