scholarly journals Impaired Expression of Chloroplast HSP90C Chaperone Activates Plant Defense Responses with a Possible Link to a Disease-Symptom-Like Phenotype

2020 ◽  
Vol 21 (12) ◽  
pp. 4202 ◽  
Author(s):  
Shaikhul Islam ◽  
Sachin Ashok Bhor ◽  
Keisuke Tanaka ◽  
Hikaru Sakamoto ◽  
Takashi Yaeno ◽  
...  
Keyword(s):  
Cell Death ◽  
Immune Responses ◽  
Tobacco Plant ◽  
Defense Responses ◽  
Blue Staining ◽  
H2o2 Production ◽  
Gene Ontology Analysis ◽  
Rna Seq ◽  
Plant Defense Responses ◽  
Cell Death Pathways

RNA-seq analysis of a transgenic tobacco plant, i-hpHSP90C, in which chloroplast HSP90C genes can be silenced in an artificially inducible manner resulting in the development of chlorosis, revealed the up- and downregulation of 2746 and 3490 genes, respectively. Gene ontology analysis of these differentially expressed genes indicated the upregulation of ROS-responsive genes; the activation of the innate immunity and cell death pathways; and the downregulation of genes involved in photosynthesis, plastid organization, and cell cycle. Cell death was confirmed by trypan blue staining and electrolyte leakage assay, and the H2O2 production was confirmed by diaminobenzidine staining. The results collectively suggest that the reduced levels of HSP90C chaperone lead the plant to develop chlorosis primarily through the global downregulation of chloroplast- and photosynthesis-related genes and additionally through the light-dependent production of ROS, followed by the activation of immune responses, including cell death.

scholarly journals Impaired expression of chloroplast HSP90C chaperone activates plant defense responses leading to a disease symptom-like phenotype

2020 ◽  
Author(s):  
Islam Shaikhul ◽  
Bhor Sachin Ashok ◽  
Tanaka Keisuke ◽  
Sakamoto Hikaru ◽  
Yaeno Takashi ◽  
...  
Keyword(s):  
Immune Response ◽  
Cell Death ◽  
Protein Quality ◽  
Tobacco Plant ◽  
Defense Responses ◽  
Blue Staining ◽  
Rna Seq ◽  
Plant Defense Responses ◽  
Cell Death Pathways ◽  
Stress Responsive Genes

AbstractRNA-seq analysis of a transgenic tobacco plant, i-hpHSP90C, in which chloroplast HSP90C genes can be silenced in an artificially inducible manner resulting in the development of chlorosis, revealed the up- and down-regulation of 2746 and 3490 genes, respectively. Gene Ontology analysis of these differentially expressed genes indicated the upregulation of ROS-responsive genes, the activation of the innate immunity and cell death pathways, and the downregulation of genes involved in photosynthesis, plastid organization, and cell cycle. Cell death was confirmed by trypan blue staining and electrolyte leakage assay and the H2O2 production by diaminobenzidine staining. The upregulation of ER stress-responsive genes suggested the interplay between ER protein quality control and chloroplast or immune response. The results collectively suggest that the reduced levels of HSP90C chaperone leads the plant to develop chlorosis primarily through the global downregulation of chloroplast and photosynthesis-related genes and additionally through the light-dependent production of ROS, followed by the activation of immune responses including the cell death.HighlightInduced silencing of HSP90C gene caused the upregulation of stress-responsive genes and the activation of innate immune response, which resulted in the chlorosis development accompanying cell death.

scholarly journals An efficient direct screening system for microorganisms that activate plant immune responses based on plant–microbe interactions using cultured plant cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mari Kurokawa ◽  
Masataka Nakano ◽  
Nobutaka Kitahata ◽  
Kazuyuki Kuchitsu ◽  
Toshiki Furuya
Keyword(s):  
Immune Responses ◽  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Large Scale ◽  
Plant Cells ◽  
Defense Responses ◽  
Root Tip ◽  
General Strategy ◽  
Plant Defense Responses ◽  
Microbe Interactions

AbstractMicroorganisms that activate plant immune responses have attracted considerable attention as potential biocontrol agents in agriculture because they could reduce agrochemical use. However, conventional methods to screen for such microorganisms using whole plants and pathogens are generally laborious and time consuming. Here, we describe a general strategy using cultured plant cells to identify microorganisms that activate plant defense responses based on plant–microbe interactions. Microbial cells were incubated with tobacco BY-2 cells, followed by treatment with cryptogein, a proteinaceous elicitor of tobacco immune responses secreted by an oomycete. Cryptogein-induced production of reactive oxygen species (ROS) in BY-2 cells served as a marker to evaluate the potential of microorganisms to activate plant defense responses. Twenty-nine bacterial strains isolated from the interior of Brassica rapa var. perviridis plants were screened, and 8 strains that enhanced cryptogein-induced ROS production in BY-2 cells were selected. Following application of these strains to the root tip of Arabidopsis seedlings, two strains, Delftia sp. BR1R-2 and Arthrobacter sp. BR2S-6, were found to induce whole-plant resistance to bacterial pathogens (Pseudomonas syringae pv. tomato DC3000 and Pectobacterium carotovora subsp. carotovora NBRC 14082). Pathogen-induced expression of plant defense-related genes (PR-1, PR-5, and PDF1.2) was enhanced by the pretreatment with strain BR1R-2. This cell–cell interaction-based platform is readily applicable to large-scale screening for microorganisms that enhance plant defense responses under various environmental conditions.

scholarly journals Transcriptome analysis of xa5-mediated resistance to bacterial leaf streak in rice (Oryza sativa L.)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiaofang Xie ◽  
Zhiwei Chen ◽  
Binghui Zhang ◽  
Huazhong Guan ◽  
Yan Zheng ◽  
...  
Keyword(s):  
Cell Death ◽  
Molecular Mechanism ◽  
Oryza Sativa L ◽  
Blast Resistance ◽  
Rna Seq ◽  
Bacterial Leaf Streak ◽  
Wild Type ◽  
Cell Death Pathways ◽  
Rnai Line ◽  
Transgenic Lines

Abstract Bacterial leaf steak (BLS) caused by Xanthomonas oryzae pv. oryzicola (Xoc) is a devastating disease in rice production. The resistance to BLS in rice is a quantitatively inherited trait, of which the molecular mechanism is still unclear. It has been proved that xa5, a recessive bacterial blast resistance gene, is the most possible candidate gene of the QTL qBlsr5a for BLS resistance. To study the molecular mechanism of xa5 function in BLS resistance, we created transgenic lines with RNAi of Xa5 (LOC_Os05g01710) and used RNA-seq to analyze the transcriptomes of a Xa5-RNAi line and the wild-type line at 9 h after inoculation with Xoc, with the mock inoculation as control. We found that Xa5-RNAi could (1) increase the resistance to BLS as expected from xa5; (2) alter (mainly up-regulate) the expression of hundreds of genes, most of which were related to disease resistance; and (3) greatly enhance the response of thousands of genes to Xoc infection, especially of the genes involved in cell death pathways. The results suggest that xa5 is the cause of BLS-resistance of QTL qBlsr5a and it displays BLS resistance effect probably mainly because of the enhanced response of the cell death-related genes to Xoc infection.

scholarly journals A Verticillium dahliae Extracellular Cutinase Modulates Plant Immune Responses

2018 ◽  
Vol 31 (2) ◽  
pp. 260-273 ◽  
Author(s):  
Yue-Jing Gui ◽  
Wen-Qi Zhang ◽  
Dan-Dan Zhang ◽  
Lei Zhou ◽  
Dylan P. G. Short ◽  
...  
Keyword(s):  
Cell Death ◽  
Plant Defense ◽  
Verticillium Dahliae ◽  
Fungal Pathogens ◽  
Sequence Divergence ◽  
Defense Responses ◽  
Carbohydrate Binding ◽  
Dependent Manner ◽  
Virus Induced Gene Silencing ◽  
Plant Defense Responses

Cutinases have been implicated as important enzymes during the process of fungal infection of aerial plant organs. The function of cutinases in the disease cycle of fungal pathogens that invade plants through the roots has been less studied. Here, functional analysis of 13 cutinase (carbohydrate esterase family 5 domain–containing) genes (VdCUTs) in the highly virulent vascular wilt pathogen Verticillium dahliae Vd991 was performed. Significant sequence divergence in cutinase family members was observed in the genome of V. dahliae Vd991. Functional analyses demonstrated that only VdCUT11, as purified protein, induced cell death and triggered defense responses in Nicotiana benthamiana, cotton, and tomato plants. Virus-induced gene silencing showed that VdCUT11 induces plant defense responses in Nicotiana benthamania in a BAK1 and SOBIR-dependent manner. Furthermore, coinfiltration assays revealed that the carbohydrate-binding module family 1 protein (VdCBM1) suppressed VdCUT11-induced cell death and other defense responses in N. benthamiana. Targeted deletion of VdCUT11 in V. dahliae significantly compromised virulence on cotton plants. The cutinase VdCUT11 is an important secreted enzyme and virulence factor that elicits plant defense responses in the absence of VdCBM1.

scholarly journals molecular link from PAMP perception to a MAPK cascade associated with tomato disease resistance

2012 ◽  
Author(s):  
Guido Sessa ◽  
Gregory B. Martin
Keyword(s):  
Cell Death ◽  
Disease Resistance ◽  
Immune Responses ◽  
Map Kinase ◽  
Pseudomonas Syringae ◽  
Molecular Mechanisms ◽  
Plant Immunity ◽  
Defense Responses ◽  
Research Activities ◽  
Mapk Cascades

The research problem: The detection of pathogen-associated molecular patterns (PAMPs) by plant pattern recognition receptors (PRRs) is a key mechanism by which plants activate an effective immune response against pathogen attack. MAPK cascades are important signaling components downstream of PRRs that transduce the PAMP signal to activate various defense responses. Preliminary experiments suggested that the receptor-like cytoplasmickinase (RLCK) Mai5 plays a positive role in pattern-triggered immunity (PTI) and interacts with the MAPKKK M3Kε. We thus hypothesized that Mai5, as other RLCKs, functions as a component PRR complexes and acts as a molecular link between PAMP perception and activation of MAPK cascades. Original goals: The central goal of this research was to investigate the molecular mechanisms by which Mai5 and M3Kε regulate plant immunity. Specific objectives were to: 1. Determine the spectrum of PAMPs whose perception is transmitted by M3Kε; 2. Identify plant proteins that act downstream of M3Kε to mediate PTI; 3. Investigate how and where Mai5 interacts with M3Kε in the plant cell; 4. Examine the mechanism by which Mai5 contributes to PTI. Changes in research directions: We did not find convincing evidence for the involvement of M3Kε in PTI signaling and substituted objectives 1 and 3 with research activities aimed at the analysis of transcriptomic profiles of tomato plants during the onset of plant immunity, isolation of the novel tomato PRR FLS3, and investigation of the involvement of the RLCKBSKs in PTI. Main achievements during this research program are in the following major areas: 1. Functional characterization of Mai5. The function of Mai5 in PTI signaling was demonstrated by testing the effect of silencing the Mai5 gene by virus-induced gene silencing (VIGS) experiments and in cell death assays. Domains of Mai5 that interact with MAPKKKs and subcellular localization of Mai5 were analyzed in detail. 2. Analysis of transcriptional profiles during the tomato immune responses to Pseudomonas syringae (Pombo et al., 2014). We identified tomato genes whose expression is induced specifically in PTI or in effector-triggered immunity (ETI). Thirty ETI-specific genes were examined by VIGS for their involvement in immunity and the MAPKKK EPK1, was found to be required for ETI. 3. Dissection of MAP kinase cascades downstream of M3Kε (Oh et al., 2013; Teper et al., 2015). We identified genes that encode positive (SGT and EDS1) and negative (WRKY1 and WRKY2) regulators of the ETI-associated cell death mediated by M3Kε. In addition, the MKK2 MAPKK, which acts downstream of M3Kε, was found to interact with the MPK3 MAPK and specific MPK3 amino acids involved interaction were identified and found to be required for induction of cell death. We also identified 5 type III effectors of the bacterial pathogen Xanthomonaseuvesicatoria that inhibited cell death induced by components of ETI-associated MAP kinase cascades. 4. Isolation of the tomato PRR FLS3 (Hind et al., submitted). FLS3, a novel PRR of the LRR-RLK family that specifically recognizes the flagellinepitope flgII-28 was isolated. FLS3 was shown to bind flgII-28, to require kinase activity for function, to act in concert with BAK1, and to enhance disease resistance to Pseudomonas syringae. 5. Functional analysis of RLCKs of the brassinosteroid signaling kinase (BSK) family.Arabidopsis and tomato BSKs were found to interact with PRRs. In addition, certain ArabidospsisBSK mutants were found to be impaired in PAMP-induced resistance to Pseudomonas syringae. Scientific and agricultural significance: Our research activities discovered and characterized new molecular components of signaling pathways mediating recognition of invading pathogens and activation of immune responses against them. Increased understanding of molecular mechanisms of immunity will allow them to be manipulated by both molecular breeding and genetic engineering to produce plants with enhanced natural defense against disease.

scholarly journals Allelic Variants of the Pseudomonas syringae Type III Effector HopZ1 Are Differentially Recognized by Plant Resistance Systems

2009 ◽  
Vol 22 (2) ◽  
pp. 176-189 ◽  
Author(s):  
Huanbin Zhou ◽  
Robyn L. Morgan ◽  
David S. Guttman ◽  
Wenbo Ma
Keyword(s):  
Cell Death ◽  
Pseudomonas Syringae ◽  
Plant Resistance ◽  
Type Iii Secretion ◽  
Defense Responses ◽  
Plant Defense Responses ◽  
Type Iii Effectors ◽  
Type Iii ◽  
New Evidence ◽  
Bacterial Plant Pathogen

The bacterial plant pathogen Pseudomonas syringae depends on the type III secretion system and type III-secreted effectors to cause disease in plants. HopZ is a diverse family of type III effectors widely distributed in P. syringae isolates. Among the HopZ homologs, HopZ1 is ancient to P. syringae and has been shown to be under strong positive selection driven by plant resistance-imposed selective pressure. Here, we characterized the virulence and avirulence functions of the three HopZ1 alleles in soybean and Nicotiana benthamiana. In soybean, HopZ1 alleles have distinct functions: HopZ1a triggers defense response, HopZ1b promotes bacterial growth, and HopZ1c has no observable effect. In N. benthamiana, HopZ1a and HopZ1b both induce plant defense responses. However, they appear to trigger different resistance pathways, evidenced by two major differences between HopZ1a- and HopZ1b-triggered hypersensitive response (HR): i) the putative N-acylation sites had no effect on HopZ1a-triggered cell death, whereas it greatly enhanced HopZ1b-triggered cell death; and ii) the HopZ1b-triggered HR, but not the HopZ1a-triggered HR, was suppressed by another HopZ homolog, HopZ3. We previously demonstrated that HopZ1a most resembled the ancestral allelic form of HopZ1; therefore, this new evidence suggested that differentiated resistance systems have evolved in plant hosts to adapt to HopZ1 diversification in P. syringae.

scholarly journals Transcriptome Analysis of xa5-mediated Resistance to Bacterial Leaf Streak in Rice (Oryza sativa L.)

2019 ◽  
Author(s):  
Xiaofang Xie ◽  
Zhiwei Chen ◽  
Huazhong Guan ◽  
Yan Zheng ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Cell Death ◽  
Molecular Mechanism ◽  
Oryza Sativa L ◽  
Blast Resistance ◽  
Rna Seq ◽  
Bacterial Leaf Streak ◽  
Wild Type ◽  
Cell Death Pathways ◽  
Rnai Line ◽  
Transgenic Lines

AbstractBacterial leaf steak (BLS) caused by Xanthomonas oryzae pv. oryzicola (Xoc) is a devastating disease in rice production. The resistance to BLS in rice is a quantitatively inherited trait, of which the molecular mechanism is still unclear. It has been proved that xa5, a recessive bacterial blast resistance gene, is the most possible candidate gene of the QTL qBlsr5a for BLS resistance. To study the molecular mechanism of xa5 function in BLS resistance, we created transgenic lines with RNAi of Xa5 (LOC_Os05g01710) and used RNA-seq to analyze the transcriptomes of a Xa5-RNAi line and the wild-type line at 9 h after inoculation with Xoc, with the mock inoculation with water as control. The results showed that Xa5-RNAi could (1) increase the resistance to BLS as expected from xa5; (2) alter (mainly up-regulate) the expression of hundreds of genes, most of which were related to disease resistance; and (3) greatly enhance the response of thousands of genes to Xoc infection, especially of the genes involved in cell death pathways, suggesting that xa5 displays BLS resistance effect probably mainly because of the enhanced response of the cell death-related genes to Xoc infection.

scholarly journals Role of Damage-Associated Molecular Pattern/Cell Death Pathways in Vaccine-Induced Immunity

Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2340
Author(s):  
Sun Min Lee ◽  
Paul Kim ◽  
Jinsuh You ◽  
Eui Ho Kim
Keyword(s):  
Cell Death ◽  
Immune Responses ◽  
Natural Infection ◽  
Cell Death Pathways ◽  
Molecular Pattern ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns ◽  
Induced Immunity ◽  
Pathogenic Infection

Immune responses induced by natural infection and vaccination are known to be initiated by the recognition of microbial patterns by cognate receptors, since microbes and most vaccine components contain pathogen-associated molecular patterns. Recent discoveries on the roles of damage-associated molecular patterns (DAMPs) and cell death in immunogenicity have improved our understanding of the mechanism underlying vaccine-induced immunity. DAMPs are usually immunologically inert, but can transform into alarming signals to activate the resting immune system in response to pathogenic infection, cellular stress and death, or tissue damage. The activation of DAMPs and cell death pathways can trigger local inflammation, occasionally mediating adaptive immunity, including antibody- and cell-mediated immune responses. Emerging evidence indicates that the components of vaccines and adjuvants induce immunogenicity via the stimulation of DAMP/cell death pathways. Furthermore, strategies for targeting this pathway to enhance immunogenicity are being investigated actively. In this review, we describe various DAMPs and focus on the roles of DAMP/cell death pathways in the context of vaccines for infectious diseases and cancer.

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