The <i>Arabidopsis thaliana JASMONATE INSENSITIVE 1</i> Gene Is Required for Suppression of Salicylic Acid-Dependent Defenses During Infection by <i>Pseudomonas syringae</i>

Laurie-Berry, Neva; Joardar, Vinita; Street, Ian H.; Kunkel, Barbara N.

doi:10.1094/mpmi-19-0789

Cited by 223 publications

(154 citation statements)

References 72 publications

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“…Contrary to insects that activate the JA pathway and trigger a strong defense response, this bacterial pathogen activates the JA pathway to promote susceptibility (Feys et al, 1994;Kloek et al, 2001;Laurie-Berry et al, 2006). Consistent with previous reports, the JA-insensitive mutants coi1-1 and myc2 showed increased resistance (both in terms of bacterial growth and leaf symptoms) that correlated with their levels of JA insensitivity ( Figures 10A and 10B).…”

Section: Analysis Of Ja-dependent Defense Responsessupporting

confidence: 89%

TheArabidopsisbHLH Transcription Factors MYC3 and MYC4 Are Targets of JAZ Repressors and Act Additively with MYC2 in the Activation of Jasmonate Responses

et al. 2011

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Jasmonates (JAs) trigger an important transcriptional reprogramming of plant cells to modulate both basal development and stress responses. In spite of the importance of transcriptional regulation, only one transcription factor (TF), the Arabidopsis thaliana basic helix-loop-helix MYC2, has been described so far as a direct target of JAZ repressors. By means of yeast two-hybrid screening and tandem affinity purification strategies, we identified two previously unknown targets of JAZ repressors, the TFs MYC3 and MYC4, phylogenetically closely related to MYC2. We show that MYC3 and MYC4 interact in vitro and in vivo with JAZ repressors and also form homo-and heterodimers with MYC2 and among themselves. They both are nuclear proteins that bind DNA with sequence specificity similar to that of MYC2. Loss-of-function mutations in any of these two TFs impair full responsiveness to JA and enhance the JA insensitivity of myc2 mutants. Moreover, the triple mutant myc2 myc3 myc4 is as impaired as coi1-1 in the activation of several, but not all, JA-mediated responses such as the defense against bacterial pathogens and insect herbivory. Our results show that MYC3 and MYC4 are activators of JAregulated programs that act additively with MYC2 to regulate specifically different subsets of the JA-dependent transcriptional response. INTRODUCTIONThe plant hormones jasmonates (JAs) are fatty acid-derived oxylipins required for the regulation of multiple physiological aspects of plant growth, development, and defense (Wasternack, 2007;Kazan and Manners, 2008;Browse, 2009;Pauwels et al., 2009). Thus, JAs are widely recognized as regulators of plant responses to environmental stresses such as pathogen and pest attack, wounding, ozone exposure, and water deficit (Devoto et al., 2005;Browse and Howe, 2008). They are also important regulators of growth and developmental programs such as gamete development, the cell cycle, root growth, tendril coiling, and senescence in many plant species (Pauwels et al., 2008;Zhang and Turner, 2008;Reinbothe et al., 2009;Yoshida et al., 2009). JAs are being recognized as important integrators of developmental and stress signals to modulate the allocation of resources to grow or to defend (Moreno et al., 2009;Robson et al., 2010).Transcription is a major regulatory step in the activation of these responses, and JAs trigger an important transcriptional reprogramming of the cells to switch the basal developmental programs into the necessary stress response program (Reymond et al., 2004;Devoto et al., 2005;Mandaokar et al., 2006;Pauwels et al., 2008). The signaling events that lead to transcriptional reprogramming are starting to be elucidated. Upon elicitation by exogenous or endogenous signals, the hormone (+)-7-iso-jasmonoyl-L-isoleucine [also known as (3R,7S)-jasmonoyl-L-isoleucine or JA-Ile] is synthesized by JAR1 (Fonseca et al., 2009b;Suza et al., 2010;Wasternack and Kombrink, 2010). JA-Ile is perceived by a receptor complex formed by the protein COI1 and the JAZ repressors (Xie et al., 1998;Thines et...

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Section: Analysis Of Ja-dependent Defense Responsessupporting

confidence: 89%

TheArabidopsisbHLH Transcription Factors MYC3 and MYC4 Are Targets of JAZ Repressors and Act Additively with MYC2 in the Activation of Jasmonate Responses

et al. 2011

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“…Next, we examined the response of ber6 plants to infection by Pseudomonas syringae pv tomato (Pst) DC3000. As measured by leaf symptoms ( Figure 1F) and pathogen growth ( Figure 1G) of the infected plants, the effects of Pst DC3000 infection in ber6 are largely similar to those in the coi1-2 mutant, which harbors a point mutation of the JA receptor gene COI1 and therefore is resistant to Pst DC3000 (Kloek et al, 2001;Xu et al, 2002;Laurie-Berry et al, 2006). Together, our results support that ber6 is a JA signaling mutant that is defective in JA-induced defense gene expression.…”

Section: Resultssupporting

confidence: 67%

The Arabidopsis Mediator Subunit MED25 Differentially Regulates Jasmonate and Abscisic Acid Signaling through Interacting with the MYC2 and ABI5 Transcription Factors

et al. 2012

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Transcriptional regulation plays a central role in plant hormone signaling. At the core of transcriptional regulation is the Mediator, an evolutionarily conserved, multisubunit complex that serves as a bridge between gene-specific transcription factors and the RNA polymerase machinery to regulate transcription. Here, we report the action mechanisms of the MEDIATOR25 (MED25) subunit of the Arabidopsis thaliana Mediator in regulating jasmonate-and abscisic acid (ABA)-triggered gene transcription. We show that during jasmonate signaling, MED25 physically associates with the basic helix-loophelix transcription factor MYC2 in promoter regions of MYC2 target genes and exerts a positive effect on MYC2-regulated gene transcription. We also show that MED25 physically associates with the basic Leu zipper transcription factor ABA-INSENSITIVE5 (ABI5) in promoter regions of ABI5 target genes and shows a negative effect on ABI5-regulated gene transcription. Our results reveal that underlying the distinct effects of MED25 on jasmonate and ABA signaling, the interaction mechanisms of MED25 with MYC2 and ABI5 are different. These results highlight that the MED25 subunit of the Arabidopsis Mediator regulates a wide range of signaling pathways through selectively interacting with specific transcription factors.

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“…Contrary to necrotrophic pathogens, which activate the JA pathway and trigger a strong defense response, Pst produces a JA-mimicking phytotoxin, coronatine (COR), which can induce a set of JA-responsive genes to promote susceptibility (Laurie-Berry et al, 2006). As expected, we found that Pst induced RGL3 expression in leaves 3 d after inoculation (Figures 7A and 7B).…”

Section: Rgl3 Modulates Ja-dependent Plant Defense Responsessupporting

confidence: 72%

The Arabidopsis DELLA RGA-LIKE3 Is a Direct Target of MYC2 and Modulates Jasmonate Signaling Responses

et al. 2012

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Gibberellins (GAs) are plant hormones involved in the regulation of plant growth in response to endogenous and environmental signals. GA promotes growth by stimulating the degradation of nuclear growth-repressing DELLA proteins. In Arabidopsis thaliana, DELLAs consist of a small family of five proteins that display distinct but also overlapping functions in repressing GA responses. This study reveals that DELLA RGA-LIKE3 (RGL3) protein is essential to fully enhance the jasmonate (JA)-mediated responses. We show that JA rapidly induces RGL3 expression in a CORONATINE INSENSITIVE1 (COI1)-and JASMONATE INSENSITIVE1 (JIN1/MYC2)-dependent manner. In addition, we demonstrate that MYC2 binds directly to RGL3 promoter. Furthermore, we show that RGL3 (like the other DELLAs) interacts with JA ZIM-domain (JAZ) proteins, key repressors of JA signaling. These findings suggest that JA/MYC2-dependent accumulation of RGL3 represses JAZ activity, which in turn enhances the expression of JA-responsive genes. Accordingly, we show that induction of primary JA-responsive genes is reduced in the rgl3-5 mutant and enhanced in transgenic lines overexpressing RGL3. Hence, RGL3 positively regulates JA-mediated resistance to the necrotroph Botrytis cinerea and susceptibility to the hemibiotroph Pseudomonas syringae. We propose that JA-mediated induction of RGL3 expression is of adaptive significance and might represent a recent functional diversification of the DELLAs.

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The Arabidopsis thaliana JASMONATE INSENSITIVE 1 Gene Is Required for Suppression of Salicylic Acid-Dependent Defenses During Infection by Pseudomonas syringae

Cited by 223 publications

References 72 publications

TheArabidopsisbHLH Transcription Factors MYC3 and MYC4 Are Targets of JAZ Repressors and Act Additively with MYC2 in the Activation of Jasmonate Responses

TheArabidopsisbHLH Transcription Factors MYC3 and MYC4 Are Targets of JAZ Repressors and Act Additively with MYC2 in the Activation of Jasmonate Responses

The Arabidopsis Mediator Subunit MED25 Differentially Regulates Jasmonate and Abscisic Acid Signaling through Interacting with the MYC2 and ABI5 Transcription Factors

The Arabidopsis DELLA RGA-LIKE3 Is a Direct Target of MYC2 and Modulates Jasmonate Signaling Responses

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