@article{ec2668f208614b7f8e17fe95578dc4a9,
title = "Overexpression of Arabidopsis microRNA167 induces salicylic acid-dependent defense against Pseudomonas syringae through the regulation of its targets ARF6 and ARF8",
abstract = "microRNAs are powerful regulators of growth, development, and stress responses in plants. The Arabidopsis thaliana microRNA miR167 was previously found to regulate diverse processes including flower development, root development, and response to osmotic stress by controlling the patterns of expression of its target genes AUXIN RESPONSE FACTOR 6 (ARF6), ARF8, and IAA-Ala RESISTANT 3. Here, we report that miR167 also modulates defense against pathogens through ARF6 and ARF8. miR167 is differentially expressed in response to the bacterial pathogen Pseudomonas syringae, and overexpression of miR167 confers very high levels of resistance. This resistance appears to be due to suppression of auxin responses and is partially dependent upon salicylic acid signaling, and also depends upon altered stomatal behavior in these plants. Closure of stomata upon the detection of P. syringae is an important aspect of the basal defense response, as it prevents bacterial cells from entering the leaf interior and causing infection. Plants overexpressing miR167 constitutively maintain small stomatal apertures, resulting in very high resistance when the pathogen is inoculated onto the leaf surface. Additionally, the systemic acquired resistance (SAR) response is severely compromised in plants overexpressing miR167, in agreement with previous work showing that the activation of SAR requires intact auxin signaling responses. This work highlights a new role for miR167, and also emphasizes the importance of hormonal balance in short- and long-term defense and of stomata as an initial barrier to pathogen entry.",
keywords = "auxin (AUX), biotic stress, hormone signaling, microRNA, plant defense response, salicylic acid (SA)",
author = "Caruana, {Julie C.} and Nikhilesh Dhar and Ramesh Raina",
note = "Funding Information: Work in the laboratory of R.R. was supported by a grant from the National Science Foundation (IOS-1146128). J.C. was supported in part by a Syracuse University Fellowship. We thank Dr. Jason Reed (University of North Carolina at Chapel Hill) for helpful discussions on the manuscript as well as for providing P35S::MIR167a, mARF6, and mARF8 contruct and arf6-2 arf8-3 seeds. Pseudomonas syringae strains were provided by Dr. Barbara Kunkel (Washington University). eds16-1 mutant seeds were provided by Dr. Mary Wildermuth (Wildermuth et al., 2001), and DR5::GUS seeds were provided by Dr. Tom Guilfoyle (Ulmasov et al., 1997). This work was supported by an NSF Arabidopsis 2010 grant (DEB0313492) and funds from Syracuse University to RR. JC was supported in part by a Syracuse University Scholarship. Funding Information: Work in the laboratory of R.R. was supported by a grant from the National Science Foundation (IOS‐1146128). J.C. was supported in part by a Syracuse University Fellowship. Funding Information: We thank Dr. Jason Reed (University of North Carolina at Chapel Hill) for helpful discussions on the manuscript as well as for providing , and contruct and seeds. strains were provided by Dr. Barbara Kunkel (Washington University). mutant seeds were provided by Dr. Mary Wildermuth (Wildermuth et al., 2001 ), and seeds were provided by Dr. Tom Guilfoyle (Ulmasov et al., 1997 ). This work was supported by an NSF Arabidopsis 2010 grant (DEB0313492) and funds from Syracuse University to RR. JC was supported in part by a Syracuse University Scholarship. P::MIR167a 35S mARF6, mARF8 arf6‐2 arf8‐3 Pseudomonas syringae eds16‐1 DR5::GUS Publisher Copyright: {\textcopyright} 2020 The Authors. Plant Direct published by American Society of Plant Biologists and the Society for Experimental Biology and John Wiley & Sons Ltd",
year = "2020",
month = sep,
day = "1",
doi = "10.1002/pld3.270",
language = "English (US)",
volume = "4",
journal = "Plant Direct",
issn = "2475-4455",
publisher = "John Wiley and Sons Inc.",
number = "9",
}