scholarly journals Cucumber Mildew Resistance Locus O Interacts with Calmodulin and Regulates Plant Cell Death Associated with Plant Immunity

2019 ◽  
Vol 20 (12) ◽  
pp. 2995 ◽  
Author(s):  
Guangchao Yu ◽  
Xiangyu Wang ◽  
Qiumin Chen ◽  
Na Cui ◽  
Yang Yu ◽  
...  
Keyword(s):  
Cell Death ◽  
Fluorescent Protein ◽  
Plant Immunity ◽  
Bimolecular Fluorescence Complementation ◽  
Marker Genes ◽  
Resistance Locus ◽  
Callose Deposition ◽  
Cucumis Sativus L ◽  
Hypersensitive Cell Death ◽  
Mildew Resistance

Pathogen-induced cell death is closely related to plant disease susceptibility and resistance. The cucumber (Cucumis sativus L.) mildew resistance locus O (CsMLO1) and calmodulin (CsCaM3) genes, as molecular components, are linked to nonhost resistance and hypersensitive cell death. In this study, we demonstrate that CsMLO1 interacts with CsCaM3 via yeast two-hybrid, firefly luciferase (LUC) complementation and bimolecular fluorescence complementation (BiFC) experiments. A subcellular localization analysis of green fluorescent protein (GFP) fusion reveals that CsCaM3 is transferred from the cytoplasm to the plasma membrane in Nicotiana benthamiana, and CsCaM3 green fluorescence is significantly attenuated via the coexpression of CsMLO1 and CsCaM3. CsMLO1 negatively regulates CsCaM3 expression in transiently transformed cucumbers, and hypersensitive cell death is disrupted by CsCaM3 and/or CsMLO1 expression under Corynespora cassiicola infection. Additionally, CsMLO1 silencing significantly enhances the expression of reactive oxygen species (ROS)-related genes (CsPO1, CsRbohD, and CsRbohF), defense marker genes (CsPR1 and CsPR3) and callose deposition-related gene (CsGSL) in infected cucumbers. These results suggest that the interaction of CsMLO1 with CsCaM3 may act as a cell death regulator associated with plant immunity and disease.

scholarly journals CaHDZ27, a Homeodomain-Leucine Zipper I Protein, Positively Regulates the Resistance to Ralstonia solanacearum Infection in Pepper

2017 ◽  
Vol 30 (12) ◽  
pp. 960-973 ◽  
Author(s):  
Shaoliang Mou ◽  
Zhiqin Liu ◽  
Feng Gao ◽  
Sheng Yang ◽  
Meixia Su ◽  
...  
Keyword(s):  
Ralstonia Solanacearum ◽  
Leucine Zipper ◽  
Fluorescent Protein ◽  
Plant Immunity ◽  
Bimolecular Fluorescence Complementation ◽  
Marker Genes ◽  
Plant Responses ◽  
Dependent Manner ◽  
Virus Induced Gene Silencing ◽  
Green Fluorescent

Homeodomain-leucine zipper class I (HD-Zip I) transcription factors have been functionally characterized in plant responses to abiotic stresses, but their roles in plant immunity are poorly understood. Here, a HD-Zip I gene, CaHZ27, was isolated from pepper (Capsicum annum) and characterized for its role in pepper immunity. Quantitative real-time polymerase chain reaction showed that CaHDZ27 was transcriptionally induced by Ralstonia solanacearum inoculation and exogenous application of methyl jasmonate, salicylic acid, or ethephon. The CaHDZ27-green fluorescent protein fused protein was targeted exclusively to the nucleus. Chromatin immunoprecipitation demonstrated that CaHDZ27 bound to the 9-bp pseudopalindromic element (CAATAATTG) and triggered β-glucuronidase expression in a CAATAATTG-dependent manner. Virus-induced gene silencing of CaHDZ27 significantly attenuated the resistance of pepper plants against R. solanacearum and downregulated defense-related marker genes, including CaHIR1, CaACO1, CaPR1, CaPR4, CaPO2, and CaBPR1. By contrast, transient overexpression of CaHDZ27 triggered strong cell death mediated by the hypersensitive response and upregulated the tested immunity-associated marker genes. Ectopic CaHDZ27 expression in tobacco enhances its resistance against R. solanacearum. These results collectively suggest that CaHDZ27 functions as a positive regulator in pepper resistance against R. solanacearum. Bimolecular fluorescence complementation and coimmunoprecipitation assays indicate that CaHDZ27 monomers bind with each other, and this binding is enhanced significantly by R. solanacearum inoculation. We speculate that homodimerization of CaHZ27 might play a role in pepper response to R. solanacearum, further direct evidence is required to confirm it.

scholarly journals XopQ induced stromule formation in Nicotiana benthamiana is causally linked to ETI signaling and depends on ADR1 and NRG1

2021 ◽  
Author(s):  
Jennifer Prautsch ◽  
Jessica L. Erickson ◽  
Sedef Özyürek ◽  
Rahel Gormannns ◽  
Lars Franke ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Nicotiana Benthamiana ◽  
Double Mutant ◽  
Plant Immunity ◽  
Signaling Cascade ◽  
Nuclear Dynamics ◽  
Hypersensitive Cell Death ◽  
Host Cell Death ◽  
Dependent Cell

In Nicotiana benthamiana, expression of the Xanthomonas effector XopQ triggers ROQ1-dependent ETI responses and in parallel accumulation of plastids around the nucleus and the formation of stromules. Both processes were proposed to contribute to ETI-related hypersensitive cell death and thereby to plant immunity. Whether these reactions are directly connected to ETI signaling events has not been tested. Here we utilized transient expression experiments to determine whether XopQ-mediated plastid reactions are a result of XopQ perception by ROQ1 or a consequence of XopQ virulence activity. We find that N. benthamiana mutants lacking ROQ1, both RNLs (NRG1 and ADR1) or EDS1, fail to elicit XopQ-dependent host cell death and stromule formation. Mutants lacking only NRG1 lost XopQ-dependent cell death but retained some stromule induction that was abolished in the RNL double mutant. This analysis aligns XopQ-induced stromules with the ETI signaling cascade but not to host programmed cell death. Furthermore, data reveal that XopQ-triggered plastid clustering is not strictly linked to stromule formation during ETI. Our data suggest that stromule formation, in contrast to chloroplast peri-nuclear dynamics, is an integral part of the N. benthamiana ETI response and that both RNL sub-types play a role in this ETI response.

scholarly journals The Role of Arabidopsis Heterotrimeric G-Protein Subunits in MLO2 Function and MAMP-Triggered Immunity

2013 ◽  
Vol 26 (9) ◽  
pp. 991-1003 ◽  
Author(s):  
Justine Lorek ◽  
Thomas Griebel ◽  
Alan M. Jones ◽  
Hannah Kuhn ◽  
Ralph Panstruga
Keyword(s):  
G Protein ◽  
G Proteins ◽  
Protein Complex ◽  
Defense Responses ◽  
Resistance Locus ◽  
Callose Deposition ◽  
Heterotrimeric G Protein ◽  
Mildew Resistance ◽  
Genetic Ablation

Heterotrimeric G-proteins, composed of Gα, Gβ, and Gγ subunits, regulate many fundamental processes in plants. In animals, ligand binding to seven transmembrane (7TM) cell surface receptors designated G-protein coupled receptors (GPCR) leads to heterotrimeric G-protein activation. Because the plant G-protein complex is constitutively active, the exact role of plant 7TM proteins in this process is unclear. Members of the mildew resistance locus O (MLO) family represent the best-characterized 7TM plant proteins. Although genetic ablation of either MLO2 or G-proteins alters susceptibility to pathogens in Arabidopsis thaliana, it is unknown whether G-proteins directly couple signaling through MLO2. Here, we exploited two well-documented phenotypes of mlo2 mutants, broad-spectrum powdery mildew resistance and spontaneous callose deposition in leaf mesophyll cells, to assess the relationship of MLO2 proteins to the G-protein complex. Although our data reveal modulation of antifungal defense responses by Gβ and Gγ subunits and a role for the Gγ1 subunit in mlo2-conditioned callose deposition, our findings overall are inconsistent with a role of MLO2 as a canonical GPCR. We discovered that mutants lacking the Gβ subunit show delayed accumulation of a subset of defense-associated genes following exposure to the microbe-associated molecular pattern flg22. Moreover, Gβ mutants were found to be hypersusceptible to spray inoculation with the bacterial pathogen Pseudomonas syringae.

scholarly journals Phenotypic Characterization of Potato Late Blight Resistance Mediated by the Broad-Spectrum Resistance Gene RB

2011 ◽  
Vol 101 (2) ◽  
pp. 263-270 ◽  
Author(s):  
Yu Chen ◽  
Dennis A. Halterman
Keyword(s):  
Cell Death ◽  
Late Blight ◽  
Partial Resistance ◽  
Avirulence Gene ◽  
Phenotypic Characterization ◽  
Solanum Bulbocastanum ◽  
Host Genotype ◽  
Wild Potato Species ◽  
Callose Deposition ◽  
Hypersensitive Cell Death

The potato gene RB, cloned from the wild potato species Solanum bulbocastanum, confers partial resistance to late blight, caused by the oomycete pathogen Phytophthora infestans. In order to better characterize this partial resistance phenotype, we have compared host resistance responses mediated by RB with those mediated by the S. demissum-derived R gene R9, which confers immunity to P. infestans carrying the corresponding avirulence gene avrR9. We found that both RB and R9 genes were capable of eliciting a hypersensitive cell death response (HR). However, in RB plants, the pathogen escaped HR lesions and continued to grow beyond the inoculation sites. We also found that callose deposition was negatively correlated with resistance levels in tested plants. Transcription patterns of pathogenesis-related (PR) genes PR-1 basic, PR-2 acidic, and PR-5 indicated that P. infestans inoculation induced transcription of these defense-related genes regardless of the host genotype; however, transcription was reduced in both the susceptible and partially resistant plants later in the infection process but remained elevated in the immune host. Most interestingly, transcription of the HR-associated gene Hin1 was suppressed in both Katahdin and RB-transgenic Katahdin but not in R9 4 days after inoculation. Together, this suggests that suppression of certain defense-related genes may allow P. infestans to spread beyond the site of infection in the partially resistant host despite elicitation of hypersensitive cell death.

scholarly journals Pseudomonas syringae pv. actinidiae Effector HopAU1 Interacts with Calcium-Sensing Receptor to Activate Plant Immunity

2022 ◽  
Vol 23 (1) ◽  
pp. 508
Author(s):  
Jinlong Zhang ◽  
Mingxia Zhou ◽  
Wei Liu ◽  
Jiajun Nie ◽  
Lili Huang
Keyword(s):  
Cell Death ◽  
Pseudomonas Syringae ◽  
Plant Pathogen ◽  
Plant Immunity ◽  
Resistance Breeding ◽  
Plant Diseases ◽  
Calcium Sensing Receptor ◽  
Callose Deposition ◽  
Calcium Sensing ◽  
Plant Pathogen Interaction

Kiwifruit canker, caused by Pseudomonas syringae pv. actinidiae (Psa), is a destructive pathogen that globally threatens the kiwifruit industry. Understanding the molecular mechanism of plant-pathogen interaction can accelerate applying resistance breeding and controlling plant diseases. All known effectors secreted by pathogens play an important role in plant-pathogen interaction. However, the effectors in Psa and their function mechanism remain largely unclear. Here, we successfully identified a T3SS effector HopAU1 which had no virulence contribution to Psa, but could, however, induce cell death and activate a series of immune responses by agroinfiltration in Nicotiana benthamiana, including elevated transcripts of immune-related genes, accumulation of reactive oxygen species (ROS), and callose deposition. We found that HopAU1 interacted with a calcium sensing receptor in N. benthamiana (NbCaS) as well as its close homologue in kiwifruit (AcCaS). More importantly, silencing CaS by RNAi in N. benthamiana greatly attenuated HopAU1-triggered cell death, suggesting CaS is a crucial component for HopAU1 detection. Further researches showed that overexpression of NbCaS in N. benthamiana significantly enhanced plant resistance against Sclerotinia sclerotiorum and Phytophthora capsici, indicating that CaS serves as a promising resistance-related gene for disease resistance breeding. We concluded that HopAU1 is an immune elicitor that targets CaS to trigger plant immunity.

scholarly journals Expression of HarpinXoo in Transgenic Tobacco Induces Pathogen Defense in the Absence of Hypersensitive Cell Death

2004 ◽  
Vol 94 (10) ◽  
pp. 1048-1055 ◽  
Author(s):  
Jian-Ling Peng ◽  
Zhi-Long Bao ◽  
Hai-Ying Ren ◽  
Jin-Sheng Wang ◽  
Han-Song Dong
Keyword(s):  
Cell Death ◽  
Transgenic Tobacco ◽  
Pathogen Resistance ◽  
Xanthomonas Oryzae ◽  
Marker Genes ◽  
Reactive Oxygen Intermediate ◽  
Pathogen Defense ◽  
Viral Pathogens ◽  
Hypersensitive Cell Death ◽  
Transgenic Expression

HarpinXoo, encoded by the hpaGXoo gene of Xanthomonas oryzae pv. oryzae, is a member of the harpin group of proteins that induce pathogen resistance and hypersensitive cell death (HCD) in plants. We elaborated whether both processes are correlated in hpaGXoo-expressing tobacco (HARTOB) plants, which produced harpinXoo intracellularly. Resistance to fungal, bacterial, and viral pathogens increased in HARTOB, in correlation with the expression of hpaGXoo, the gene NPR1 that regulates several resistance pathways, and defense genes GST1, Chia5, PR-1a, and PR-1b that are mediated by different signals. However, reactive oxygen intermediate burst, the expression of HCD marker genes hsr203 and hin1, and cell death did not occur spontaneously in HARTOB, though they did in untransformed and HARTOB plants treated exogenously with harpinXoo. Thus, the transgenic expression of harpinXoo confers nonspecific pathogen defense in the absence of HCD.

scholarly journals The Mildew Resistance Locus O 4 Interacts with CaM/CML and Is Involved in Root Gravity Response

2021 ◽  
Vol 22 (11) ◽  
pp. 5962
Author(s):  
Lei Zhu ◽  
Xue-Qin Zhang ◽  
De Ye ◽  
Li-Qun Chen
Keyword(s):  
Functional Characterization ◽  
Bimolecular Fluorescence Complementation ◽  
Resistance Locus ◽  
Yeast Two Hybrid ◽  
Mildew Resistance ◽  
Calmodulin Binding ◽  
Gravity Response ◽  
Two Hybrid ◽  
Regulate Plant Development

The plant-specific mildew resistance locus O (MLO) proteins, which contain seven transmembrane domains and a conserved calmodulin-binding domain, play important roles in many plant developmental processes. However, their mechanisms that regulate plant development remain unclear. Here, we report the functional characterization of the MLO4 protein in Arabidopsis roots. The MLO4 was identified as interacting with CML12 in a screening for the interaction between the proteins from Arabidopsis MLO and calmodulin/calmodulin-like (CaM/CML) families using yeast two hybrid (Y2H) assays. Then, the interaction between MLO4 and CML12 was further verified by Luciferase Complementation Imaging (LCI) and Bimolecular Fluorescence Complementation (BiFC) assays. Genetic analysis showed that the mlo4, cml12, and mlo4 cml12 mutants displayed similar defects in root gravity response. These results imply that the MLO4 might play an important role in root gravity response through interaction with CML12. Moreover, our results also demonstrated that the interaction between the MLO and CaM/CML families might be conservative.

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