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oai:riuma.uma.es:10630/357052026-02-03T11:25:59Zcom_10630_2254col_10630_37953

miR825-5p targets the TIR-NBS-LRR gene MIST1 and down-regulates basal immunity against Pseudomonas syringae in Arabidopsis López-Márquez, Diego Del Espino Pérez, Ángel López-Pagán, Nieves Rodrígez-Negrete, Edgar A. Rubio-Somoza, Ignacio Ruiz-Albert, Francisco Javier Rodríguez-Bejarano, Eduardo Beuzón-López, Carmen del Rosario Receptores celulares Plants encode numerous intracellular receptors known as nucleotide-binding leucine-rich repeat receptors (NLRs) that recognize pathogen-derived effectors or their activity to activate defenses. miRNAs regulate NLR genes in many species, often triggering the production of phased siRNAs (phasiRNAs). Most such examples involve genes encoding NLRs carrying coiled-coil domains, although a few include genes encoding NLRs carrying a Toll/interleukin-1 domain (TNL). Here, we characterize the role of miR825-5p in Arabidopsis, using a combination of bioinformatics, transgenic plants with altered miRNA levels and/or reporters, small RNAs, and virulence assays. We demonstrate that miR825-5p down-regulates the TNL MIST1 by targeting for endonucleolytic cleavage the sequence coding for TIR2, a highly conserved amino acid motif, linked to a catalytic residue essential for immune function. miR825-5p acts as a negative regulator of basal resistance against Pseudomonas syringae. miR825-5p triggers the production from MIST1 of a large number of phasiRNAs that can mediate cleavage of both MIST1 and additional TNL gene transcripts, potentially acting as a regulatory hub. miR825-5p is expressed in unchallenged leaves and transcriptionally downregulated in response to pathogen-associated molecular patterns (PAMPs). Our results show that miR825-5p, which is required for full expression of PAMP-triggered immunity, establishes a link between PAMP perception and expression of uncharacterized TNL genes. 2024-12-17T09:55:01Z 2024-12-17T09:55:01Z 2024-12-17T09:55:01Z 2021-10-26 journal article López-Márquez D, Del-Espino Á, López-Pagán N, Rodríguez-Negrete EA, Rubio-Somoza I, Ruiz-Albert J, Bejarano ER, Beuzón CR. miR825-5p targets the TIR-NBS-LRR gene MIST1 and down-regulates basal immunity against Pseudomonas syringae in Arabidopsis. J Exp Bot. 2021 Oct 26;72(20):7316-7334 https://hdl.handle.net/10630/35705 10.1093/jxb/erab354 eng http://creativecommons.org/licenses/by-nd/4.0/ open access Attribution-NoDerivatives 4.0 Internacional Oxford University Press