MAP kinase phosphatase1 and protein tyrosine phosphatase1 are repressors of salicylic acid synthesis and SNC1-mediated responses in Arabidopsis.
The Plant cell
Mitogen-activated protein (MAP) kinase phosphatases are important negative regulators of the levels and kinetics of MAP kinase activation that modulate cellular responses. The dual-specificity phosphatase MAP KINASE PHOSPHATASE1 (MKP1) was previously shown to regulate MAP KINASE6 (MPK6) activation levels and abiotic stress responses in Arabidopsis thaliana. Here, we report that the mkp1 null mutation in the Columbia (Col) accession results in growth defects and constitutive biotic defense responses, including elevated levels of salicylic acid, camalexin, PR gene expression, and resistance to the bacterial pathogen Pseudomonas syringae. PROTEIN TYROSINE PHOSPHATASE1 (PTP1) also interacts with MPK6, but the ptp1 null mutant shows no aberrant growth phenotype. However, the pronounced constitutive defense response of the mkp1 ptp1 double mutant reveals that MKP1 and PTP1 repress defense responses in a coordinated fashion. Moreover, mutations in MPK3 and MPK6 distinctly suppress mkp1 and mkp1 ptp1 phenotypes, indicating that MKP1 and PTP1 act as repressors of inappropriate MPK3/MPK6-dependent stress signaling. Finally, we provide evidence that the natural modifier of mkp1 in Col is largely the disease resistance gene homolog SUPPRESSOR OF npr1-1, CONSTITUTIVE 1 (SNC1) that is absent in the Wassilewskija accession. Our data thus indicate a major role of MKP1 and PTP1 in repressing salicylic acid biosynthesis in the autoimmune-like response caused by SNC1.
10.1105/tpc.109.067678
Mitogen-Activated Protein Kinase Phosphatase 1 (MKP1) Negatively Regulates the Production of Reactive Oxygen Species During Arabidopsis Immune Responses.
Escudero Viviana,Torres Miguel Ángel,Delgado Magdalena,Sopeña-Torres Sara,Swami Sanjay,Morales Jorge,Muñoz-Barrios Antonio,Mélida Hugo,Jones Alan M,Jordá Lucía,Molina Antonio
Molecular plant-microbe interactions : MPMI
Genetic ablation of the β subunit of the heterotrimeric G protein complex in agb1-2 confers defective activation of microbe-associated molecular pattern (MAMP)-triggered immunity, resulting in agb1-2 enhanced susceptibility to pathogens like the fungus Plectosphaerella cucumerina BMM. A mutant screen for suppressors of agb1-2 susceptibility (sgb) to P. cucumerina BMM identified sgb10, a new null allele (mkp1-2) of the mitogen-activated protein kinase phosphatase 1 (MKP1). The enhanced susceptibility of agb1-2 to the bacterium Pseudomonas syringae pv. tomato DC3000 and the oomycete Hyaloperonospora arabidopsidis is also abrogated by mkp1-2. MKP1 negatively balances production of reactive oxygen species (ROS) triggered by MAMPs, since ROS levels are enhanced in mkp1. The expression of RBOHD, encoding a NADPH oxidase-producing ROS, is upregulated in mkp1 upon MAMP treatment or pathogen infection. Moreover, MKP1 negatively regulates RBOHD activity, because ROS levels upon MAMP treatment are increased in mkp1 plants constitutively overexpressing RBOHD (35S::RBOHD mkp1). A significant reprograming of mkp1 metabolic profile occurs with more than 170 metabolites, including antimicrobial compounds, showing differential accumulation in comparison with wild-type plants. These results suggest that MKP1 functions downstream of the heterotrimeric G protein during MAMP-triggered immunity, directly regulating the activity of RBOHD and ROS production as well as other immune responses.
10.1094/MPMI-08-18-0217-FI
CRISPR-targeted mutagenesis of mitogen-activated protein kinase phosphatase 1 improves both immunity and yield in wheat.
Plant biotechnology journal
Plants have evolved a sophisticated immunity system for specific detection of pathogens and rapid induction of measured defences. Over- or constitutive activation of defences would negatively affect plant growth and development. Hence, the plant immune system is under tight positive and negative regulation. MAP kinase phosphatase1 (MKP1) has been identified as a negative regulator of plant immunity in model plant Arabidopsis. However, the molecular mechanisms by which MKP1 regulates immune signalling in wheat (Triticum aestivum) are poorly understood. In this study, we investigated the role of TaMKP1 in wheat defence against two devastating fungal pathogens and determined its subcellular localization. We demonstrated that knock-down of TaMKP1 by CRISPR/Cas9 in wheat resulted in enhanced resistance to rust caused by Puccinia striiformis f. sp. tritici (Pst) and powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt), indicating that TaMKP1 negatively regulates disease resistance in wheat. Unexpectedly, while Tamkp1 mutant plants showed increased resistance to the two tested fungal pathogens they also had higher yield compared with wild-type control plants without infection. Our results suggested that TaMKP1 interacts directly with dephosphorylated and activated TaMPK3/4/6, and TaMPK4 interacts directly with TaPAL. Taken together, we demonstrated TaMKP1 exert negative modulating roles in the activation of TaMPK3/4/6, which are required for MAPK-mediated defence signalling. This facilitates our understanding of the important roles of MAP kinase phosphatases and MAPK cascades in plant immunity and production, and provides germplasm resources for breeding for high resistance and high yield.
10.1111/pbi.14312
An MKP-MAPK protein phosphorylation cascade controls vascular immunity in plants.
Science advances
Global crop production is greatly reduced by vascular diseases. These diseases include bacterial blight of rice and crucifer black rot caused by pv. () and pv. (). The molecular mechanisms that activate vascular defense against such pathogens remains underexplored. Here, we show that an MAPK phosphatase 1 (MKP1) mutant has increased host susceptibility to the adapted pathogen and is compromised in nonhost resistance to the rice pathogen . MKP1 regulates MAPK-mediated phosphorylation of the transcription factor MYB4 that negatively regulates vascular lignification through inhibiting lignin biosynthesis. Induction of lignin biosynthesis is, therefore, an important part of vascular-specific immunity. The role of MKP-MAPK-MYB signaling in lignin biosynthesis and vascular resistance to is conserved in rice, indicating that these factors form a tissue-specific defense regulatory network. Our study likely reveals a major vascular immune mechanism that underlies tissue-specific disease resistance against bacterial pathogens in plants.
10.1126/sciadv.abg8723
Small holes, big impact: Stomata in plant-pathogen-climate epic trifecta.
Molecular plant
The regulation of stomatal aperture opening and closure represents an evolutionary battle between plants and pathogens, characterized by adaptive strategies that influence both plant resistance and pathogen virulence. The ongoing climate change introduces further complexity, affecting pathogen invasion and host immunity. This review delves into recent advances on our understanding of the mechanisms governing immunity-related stomatal movement and patterning with an emphasis on the regulation of stomatal opening and closure dynamics by pathogen patterns and host phytocytokines. In addition, the review explores how climate changes impact plant-pathogen interactions by modulating stomatal behavior. In light of the pressing challenges associated with food security and the unpredictable nature of climate changes, future research in this field, which includes the investigation of spatiotemporal regulation and engineering of stomatal immunity, emerges as a promising avenue for enhancing crop resilience and contributing to climate control strategies.
10.1016/j.molp.2023.11.011
A MPK3/6-WRKY33-ALD1-Pipecolic Acid Regulatory Loop Contributes to Systemic Acquired Resistance.
Wang Yiming,Schuck Stefan,Wu Jingni,Yang Ping,Döring Anne-Christin,Zeier Jürgen,Tsuda Kenichi
The Plant cell
Plants induce systemic acquired resistance (SAR) upon localized exposure to pathogens. Pipecolic acid (Pip) production via AGD2-LIKE DEFENSE RESPONSE PROTEIN1 (ALD1) is key for SAR establishment. Here, we report a positive feedback loop important for SAR induction in We showed that local activation of the MAP kinases MPK3 and MPK6 is sufficient to trigger Pip production and mount SAR. Consistent with this, mutations in or led to compromised Pip accumulation upon inoculation with the bacterial pathogen pv DC3000 () AvrRpt2, which triggers strong sustained MAPK activation. By contrast, pv and , which induce transient MAPK activation, trigger Pip biosynthesis and SAR independently of MPK3/6. expression, Pip accumulation, and SAR were compromised in mutants defective in the MPK3/6-regulated transcription factor WRKY33. Chromatin immunoprecipitation showed that WRKY33 binds to the promoter. We found that Pip triggers activation of MPK3 and MPK6 and that MAPK activation after AvrRpt2 inoculation is compromised in and mutants. Collectively, our results reveal a positive regulatory loop consisting of MPK3/MPK6, WRKY33, ALD1, and Pip in SAR induction and suggest the existence of distinct SAR activation pathways that converge at the level of Pip biosynthesis.
10.1105/tpc.18.00547
Regulation of Stomatal Immunity by Interdependent Functions of a Pathogen-Responsive MPK3/MPK6 Cascade and Abscisic Acid.
Su Jianbin,Zhang Mengmeng,Zhang Lawrence,Sun Tiefeng,Liu Yidong,Lukowitz Wolfgang,Xu Juan,Zhang Shuqun
The Plant cell
Activation of mitogen-activated protein kinases (MAPKs) is one of the earliest responses after plants sense an invading pathogen. Here, we show that MPK3 and MPK6, two pathogen-responsive MAPKs, and their upstream MAPK kinases, MKK4 and MKK5, are essential to both stomatal and apoplastic immunity. Loss of function of and , or their upstream and , abolishes pathogen/microbe-associated molecular pattern- and pathogen-induced stomatal closure. Gain-of-function activation of MPK3/MPK6 induces stomatal closure independently of abscisic acid (ABA) biosynthesis and signaling. In contrast, exogenously applied organic acids such as malate or citrate are able to reverse the stomatal closure induced by MPK3/MPK6 activation. Gene expression analysis and in situ enzyme activity staining revealed that malate metabolism increases in guard cells after activation of MPK3/MPK6 or inoculation of pathogen. In addition, pathogen-induced malate metabolism requires functional MKK4/MKK5 and MPK3/MPK6. We propose that the pathogen-responsive MPK3/MPK6 cascade and ABA are two essential signaling pathways that control, respectively, the organic acid metabolism and ion channels, two main branches of osmotic regulation in guard cells that function interdependently to control stomatal opening/closure.
10.1105/tpc.16.00577
Arabidopsis MAP kinase phosphatase 1 is phosphorylated and activated by its substrate AtMPK6.
Park Hyeong Cheol,Song Eun Hyeon,Nguyen Xuan Canh,Lee Kyunghee,Kim Kyung Eun,Kim Ho Soo,Lee Sang Min,Kim Sun Ho,Bae Dong Won,Yun Dae-Jin,Chung Woo Sik
Plant cell reports
Arabidopsis MAP kinase phosphatase 1 (AtMKP1) is a member of the mitogen-activated protein kinase (MPK) phosphatase family, which negatively regulates AtMPKs. We have previously shown that AtMKP1 is regulated by calmodulin (CaM). Here, we examined the phosphorylation of AtMKP1 by its substrate AtMPK6. Intriguingly, AtMKP1 was phosphorylated by AtMPK6, one of AtMKP1 substrates. Four phosphorylation sites were identified by phosphoamino acid analysis, TiO(2) chromatography and mass spectrometric analysis. Site-directed mutation of these residues in AtMKP1 abolished the phosphorylation by AtMPK6. In addition, AtMKP1 interacted with AtMPK6 as demonstrated by the yeast two-hybrid system. Finally, the phosphatase activity of AtMKP1 increased approximately twofold following phosphorylation by AtMPK6. By in-gel kinase assays, we showed that AtMKP1 could be rapidly phosphorylated by AtMPK6 in plants. Our results suggest that the catalytic activity of AtMKP1 in plants can be regulated not only by Ca(2+)/CaM, but also by its physiological substrate, AtMPK6.
10.1007/s00299-011-1064-4
Arabidopsis MAP Kinase Phosphatase 1 (AtMKP1) negatively regulates MPK6-mediated PAMP responses and resistance against bacteria.
Anderson Jeffrey C,Bartels Sebastian,González Besteiro Marina A,Shahollari Bationa,Ulm Roman,Peck Scott C
The Plant journal : for cell and molecular biology
A primary component of plant defense is the detection of pathogen-associated molecular patterns (PAMPs) by plasma membrane-localized pathogen recognition receptors. PAMP perception results in rapid and transient activation of phosphorylation-dependent signaling pathways that lead to a wide array of defense-related responses, including extensive changes in gene expression. In Arabidopsis, several kinases, including the mitogen-activated protein kinases (MAPKs) MPK6 and MPK3, are rapidly activated after PAMP treatment, and are thought to positively regulate a wide array of defense-related responses. In contrast, negative regulation of PAMP responses by downstream phosphatases remains poorly understood. Here we report the identification of Arabidopsis MAP Kinase Phosphatase 1 (MKP1) as a negative regulator of diverse PAMP responses, including activation of MPK6 and MPK3, transient production of extracellular reactive oxygen species, accumulation of a subset of PAMP-regulated transcripts, and inhibition of seedling growth. In agreement with the enhanced PAMP response phenotypes observed in the mkp1 mutant, we found that mkp1 seedlings and adult plants are more resistant to the virulent bacterial pathogen Pseudomonas syringae pv. tomato (Pto) DC3000. Further genetic analysis revealed that MPK6, but not MPK3, is required for the mkp1-dependent increase in resistance to Pto and enhanced PAMP-induced growth inhibition observed in mkp1 seedlings. Together, our data support a role for MKP1 as a negative regulator of MPK6-mediated PAMP responses.
10.1111/j.1365-313X.2011.04588.x