MiR858-mediated regulation of flavonoid-specific MYB transcription factor genes controls resistance to pathogen infection in Arabidopsis
Camargo Ramírez, Rosany (Centre de Recerca en Agrigenòmica)
Val-Torregrosa, Beatriz (Centre de Recerca en Agrigenòmica)
San Segundo, Blanca (Centre de Recerca en Agrigenòmica)

Data:	2018
Resum:	MicroRNAs (miRNAs) are a class of short endogenous non-coding small RNAs that direct post-transcriptional gene silencing in eukaryotes. In plants, the expression of a large number of miRNAs has been shown to be regulated during pathogen infection. However, the functional role of the majority of these pathogen-regulated miRNAs has not been elucidated. In this work, we investigated the role of Arabidopsis miR858 in the defense response of Arabidopsis plants to infection by fungal pathogens with necrotrophic (Plectosphaerella cucumerina) or hemibiotrophic (Fusarium oxysporum and Colletotrichum higginsianum) lifestyles. Whereas overexpression of MIR858 enhances susceptibility to pathogen infection, interference with miR858 activity by target mimics (MIM858 plants) results in disease resistance. Upon pathogen challenge, stronger activation of the defense genes PDF1. 2 and PR4 occurs in MIM858 plants than in wild-type plants, whereas pathogen infection induced weaker activation of these genes in MIR858 overexpressor plants. Reduced miR858 activity, and concomitant up-regulation of miR858 target genes, in MIM858 plants, also leads to accumulation of flavonoids in Arabidopsis leaves. The antifungal activity of phenylpropanoid compounds, including flavonoids, is presented. Furthermore, pathogen infection or treatment with fungal elicitors is accompanied by a gradual decrease in MIR858 expression in wild-type plants, suggesting that miR858 plays a role in PAMP (pathogen-associated molecular pattern)-triggered immunity. These data support that miR858 is a negative regulator of Arabidopsis immunity and provide new insights into the relevant role of miR858-mediated regulation of the phenylpropanoid biosynthetic pathway in controlling Arabidopsis immunity.
Ajuts:	Ministerio de Economía y Competitividad BES-2016-076289 Ministerio de Economía y Competitividad BIO2015-67212-R Ministerio de Economía y Competitividad SEV-2015-0533 Ministerio de Economía y Competitividad BIO2012-32838 Ministerio de Educación, Cultura y Deporte FPU12/02812
Nota:	Altres ajuts: CERCA Generalitat de Catalunya
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Arabidopsis thaliana ; Colletotrichum higginsianum ; Defense response ; Fusarium oxysporum ; MiR858 ; Plectosphaerella cucumerina
Publicat a:	Plant & cell physiology, Vol. 59, issue 1 (Jan. 2018) , p. 190-204, ISSN 0032-0781

DOI: 10.1093/pcp/pcx175

Post-print 29 p, 2.4 MB

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