TY - JOUR
T1 - MiR825-5p targets the TIR-NBS-LRR gene MIST1 and down-regulates basal immunity against Pseudomonas syringae in Arabidopsis
AU - López-Márquez, Diego
AU - Del-Espino, Ángel
AU - López-Pagán, Nieves
AU - Rodríguez-Negrete, Edgar A.
AU - Rubio-Somoza, Ignacio
AU - Ruiz-Albert, Javier
AU - Bejarano, Eduardo R.
AU - Beuzón, Carmen R.
N1 - Publisher Copyright:
© 2021 The Author(s). Published by Oxford University Press on behalf of the Society for Experimental Biology.
PY - 2021/10/26
Y1 - 2021/10/26
N2 - 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 down-regulated 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.
AB - 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 down-regulated 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.
KW - Arabidopsis
KW - PTI
KW - Pseudomonas syringae
KW - gene silencing
KW - miRNA
KW - phasiRNAs
KW - plant immunity
KW - resistance genes
UR - http://www.scopus.com/inward/record.url?scp=85119349608&partnerID=8YFLogxK
U2 - 10.1093/jxb/erab354
DO - 10.1093/jxb/erab354
M3 - Artículo
C2 - 34329403
AN - SCOPUS:85119349608
SN - 0022-0957
VL - 72
SP - 7316
EP - 7334
JO - Journal of Experimental Botany
JF - Journal of Experimental Botany
IS - 20
ER -