ELF18-INDUCED LONG NONCODING RNA 1 evicts fibrillarin from mediator subunit to enhance PATHOGENESIS-RELATED GENE 1 (PR1) expression

• Published in: The New phytologist Vol. 221; no. 4; pp. 2067 - 2079
• Main Authors: Seo, Jun Sung, Diloknawarit, Piyarut, Park, Bong Soo, Chua, Nam-Hai
• Format: Journal Article
• Language: English
• Published: England Wiley 01.03.2019; Wiley Subscription Services, Inc
• Subjects: Arabidopsis; Arabidopsis - genetics; Arabidopsis - immunology; Arabidopsis - metabolism; Arabidopsis - microbiology; Arabidopsis Proteins - metabolism; Complementation; Complexity; Defence mechanisms; elf18; Fibrillarin; FIBRILLARIN 2 (FIB2); Fluorescence; Gene expression; Gene Expression Regulation, Plant; Gene regulation; Genes; Genetic analysis; Immune response; Immune system; Immunity; Immunoprecipitation; long noncoding RNA (lncRNA); mediator; Mediator Complex - metabolism; Methyltransferases - metabolism; Mutation - genetics; Nucleic acids; Nucleoli; Pathogenesis; PATHOGENESIS‐RELATED GENE 1 (PR1); pathogen‐associated molecular pattern (PAMP); Pattern recognition; Phenotype; Plant immunity; plant innate immunity; Promoter Regions, Genetic; Promoters; Protein Binding; Protein Subunits - metabolism; Proteins; Pseudomonas syringae - physiology; Ribonucleic acid; RNA; RNA, Long Noncoding - genetics; RNA, Long Noncoding - metabolism; Transcription; PATHOGENESIS-RELATED GENE 1 (PR1); long noncoding RNA (lncRNA); FIBRILLARIN 2 (FIB2); Arabidopsis; plant innate immunity; elf18; mediator; pathogen-associated molecular pattern (PAMP)
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.15530

• Plant immune response is initiated upon the recognition of pathogen-associated molecular patterns such as elf18. Previously, we identified an Arabidopsis ELF18-INDUCED LONG NONCODING RNA 1 (ELENA1), as a positive transcriptional regulator of immune responsive genes. ELENA1 associated with Mediator subunit 19a (MED19a) to enhance enrichment of the complex on PATHOGENESIS-RELATED GENE 1 (PR1) promoter. • In vitro and in vivo RNA–protein interaction experiments showed that ELENA1 can also interact with FIBRILLARIN 2 (FIB2). Co-immunoprecipitation and bimolecular fluorescence complementation assay showed that FIB2 directly interacts with MED19a in nucleoplasm and nucleolus. Analysis of fib2 mutant showed that FIB2 functions as a negative transcriptional regulator for immune responsive genes, including PR1. • Genetic and biochemical analyses demonstrated that ELENA1 can dissociate the FIB2/MED19a complex and release FIB2 from PR1 promoter to enhance PR1 expression. • ELENA1 increases PR1 expression by evicting the repressor (FIB2) from the activator (MED19a). Our findings uncover an additional layer of complexity in the transcriptional regulation of plant immune responsive genes by long noncoding RNA.