scholarly journals Calcium-signaling proteins mediate the plant transcriptomic response during a well-established Xanthomonas campestris pv. campestris infection

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Maria Tortosa ◽  
Maria E. Cartea ◽  
Pablo Velasco ◽  
Pilar Soengas ◽  
Victor M. Rodriguez
Keyword(s):  
Calcium Signaling ◽  
Defense Mechanisms ◽  
Xanthomonas Campestris ◽  
Signaling Proteins ◽  
Transcriptomic Response ◽  
Expression Of Genes ◽  
Knockout Mutants ◽  
Effector Triggered Immunity ◽  
Plant Transcriptome ◽  
Molecular Patterns

Abstract The plant immune system is divided into two branches; one branch is based on the recognition of pathogen-associated molecular patterns (PAMP-triggered immunity), and the other relies on pathogenic effector detection (effector-triggered immunity). Despite each branch being involved in different complex mechanisms, both lead to transcription reprogramming and, thus, changes in plant metabolism. To study the defense mechanisms involved in the Brassica oleracea–Xanthomonas campestris pv. campestris (Xcc) interaction, we analyzed the plant transcriptome dynamics at 3 and 12 days postinoculation (dpi) by using massive analysis of 3′-cDNA ends. We identified more induced than repressed transcripts at both 3 and 12 dpi, although the response was greater at 12 dpi. Changes in the expression of genes related to the early infection stages were only detected at 12 dpi, suggesting that the timing of triggered defenses is crucial to plant survival. qPCR analyses in susceptible and resistant plants allowed us to highlight the potential role of two calcium-signaling proteins, CBP60g and SARD1, in the resistance against Xcc. This role was subsequently confirmed using Arabidopsis knockout mutants.

scholarly journals In Silico Phylogenetic and Structural Analyses of Plant Endogenous Danger Signaling Molecules upon Stress

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Athanasia Pavlopoulou ◽  
Ezgi Karaca ◽  
Alma Balestrazzi ◽  
Alexandros G. Georgakilas
Keyword(s):  
In Silico ◽  
Defense Mechanisms ◽  
Molecular Mechanisms ◽  
Conservation Status ◽  
Downstream Signaling ◽  
Protein Protein Interaction ◽  
Effector Triggered Immunity ◽  
Molecular Patterns ◽  
Dying Cells ◽  
Diverse Plant Species

The plant innate immune system has two major branches, the pathogen-triggered immunity and the effector-triggered immunity (ETI). The effectors are molecules released by plant attackers to evade host immunity. In addition to the foreign intruders, plants possess endogenous instigators produced in response to general cellular injury termed as damage-associated molecular patterns (DAMPs). In plants, DAMPs or alarmins are released by damaged, stressed, or dying cells following abiotic stress such as radiation, oxidative and drought stresses. In turn, a cascade of downstream signaling events is initiated leading to the upregulation of defense or response-related genes. In the present study, we have investigated more thoroughly the conservation status of the molecular mechanisms implicated in the danger signaling primarily in plants. Towards this direction, we have performed in silico phylogenetic and structural analyses of the associated biomolecules in taxonomically diverse plant species. On the basis of our results, the defense mechanisms appear to be largely conserved within the plant kingdom. Of note, the sequence and/or function of several components of these mechanisms was found to be conserved in animals, as well. At the same time, the molecules involved in plant defense were found to form a dense protein-protein interaction (PPi) network, suggesting a crosstalk between the various defense mechanisms to a variety of stresses, like oxidative stress.

scholarly journals Evolution of Disease Defense Genes and Their Regulators in Plants

2019 ◽  
Vol 20 (2) ◽  
pp. 335 ◽  
Author(s):  
Rongzhi Zhang ◽  
Fengya Zheng ◽  
Shugen Wei ◽  
Shujuan Zhang ◽  
Genying Li ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Plant Diseases ◽  
Regulation System ◽  
Defense Genes ◽  
Biotic Stresses ◽  
Microbial Infections ◽  
Effector Triggered Immunity ◽  
Plant Pathogen Interactions ◽  
Molecular Patterns ◽  
New Generation

Biotic stresses do damage to the growth and development of plants, and yield losses for some crops. Confronted with microbial infections, plants have evolved multiple defense mechanisms, which play important roles in the never-ending molecular arms race of plant–pathogen interactions. The complicated defense systems include pathogen-associated molecular patterns (PAMP) triggered immunity (PTI), effector triggered immunity (ETI), and the exosome-mediated cross-kingdom RNA interference (CKRI) system. Furthermore, plants have evolved a classical regulation system mediated by miRNAs to regulate these defense genes. Most of the genes/small RNAs or their regulators that involve in the defense pathways can have very rapid evolutionary rates in the longitudinal and horizontal co-evolution with pathogens. According to these internal defense mechanisms, some strategies such as molecular switch for the disease resistance genes, host-induced gene silencing (HIGS), and the new generation of RNA-based fungicides, have been developed to control multiple plant diseases. These broadly applicable new strategies by transgene or spraying ds/sRNA may lead to reduced application of pesticides and improved crop yield.

scholarly journals Plant Virus Interaction: Layers of Plant Antiviral Immunity

2019 ◽  
pp. 89-94
Author(s):  
Pedro Filho Noronha Souza
Keyword(s):  
Plant Virus ◽  
Defense Mechanisms ◽  
Second Line ◽  
Basal Resistance ◽  
Double Stranded Rna ◽  
Effector Triggered Immunity ◽  
Virus Interaction ◽  
Two Phases ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

Plant defense mechanisms are divided into two phases; (1) the Pathogen-Triggered Immunity (PTI), which is basal resistance and; (2) Effector-Triggered Immunity (ETI) or induced resistance, the second line of defense of plants [1,2]. The PTI response is rapidly active by plants after recognizing pathogens effectors, which could be MAMPS or PAMPs (Microbe/pathogen-associated molecular patterns, e.g., bacterial flagellin), DAMPs (Damage-associated molecular patterns, e.g., fungal haustorium), and VAMPs (Viral-associated molecular patterns, e.g., double-stranded RNA of viruses). The recognition of pathogens effectors is performed by Pattern Recognition Receptors (PRR) [3-6].

scholarly journals Genotypic Variation in Resistance Gene-Mediated Calcium Signaling and Hormonal Signaling Involved in Effector-Triggered Immunity or Disease Susceptibility in the Xanthomonas campestris pv. Campestris–Brassica napus Pathosystem

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 303
Author(s):  
Md. Al Mamun ◽  
Md. Tabibul Islam ◽  
Bok-Rye Lee ◽  
Van Hien La ◽  
Dong-Won Bae ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Protein Kinase ◽  
Calcium Signaling ◽  
Xanthomonas Campestris ◽  
Disease Susceptibility ◽  
R Gene ◽  
Leucine Rich Repeat ◽  
Calcium Sensing ◽  
Effector Triggered Immunity ◽  
Xanthomonas Campestris Pv Campestris

To characterize cultivar variation in resistance gene (R-gene)-mediated calcium signaling and hormonal regulation in effector-triggered immunity (ETI) and disease susceptibility, Xanthomonas campestris pv. campestris (Xcc) was inoculated in two Brassica napus cultivars (cvs. Capitol and Mosa). At 14 days post inoculation (DPI) with Xcc, there was a necrotic lesion in cv. Mosa along with the significant accumulation of H2O2 and malondialdehyde (MDA), whereas no visual symptom was observed in cv. Capitol. The cultivar variations in the R-gene expressions were found in response to Xcc. ZAR1 is a coiled-coil-nucleotide binding site-leucine-rich repeat (CC-NB-LRR)-type R-gene that is significantly induced in cv. Capitol, whereas toll/interleukin-1 receptor-nucleotide binding site-leucine-rich repeat (TIR-NB-LRR)-type R-gene, TAO1, is significantly upregulated in cv. Mosa Xcc-inoculated plants. The defense-related gene’s non-race-specific disease resistance 1 (NDR1) and mitogen-activated protein kinase 6 (MAPK6) were enhanced, whereas calcium-dependent protein kinase (CDPK5) and calcium-sensing protein 60g (CBP60g) were depressed in cv. Capitol Xcc inoculated plants, and opposite results were found in cv. Mosa. The calcium-sensing receptor (CAS), calmodulin (CaM), expression was induced in both the cultivars. However, the CAS induction rate was much higher in cv. Mosa than in cv. Capitol in response to Xcc. The phytohormone salicylic acid (SA) and jasmonic acid (JA) levels were significantly higher in cv. Capitol along with the enhanced SA receptors (NPR3 and NPR4) and JA synthesis and signaling-related gene expression (LOX2, PDF1.2), whereas the JA level was significantly lower in cv. Mosa Xcc inoculated plants. The SA synthesis and signaling-related genes (ICS1, NPR1) and SA were present at higher levels in cv. Mosa; additionally, the SA level present was much higher in the susceptible cultivar (cv. Mosa) than in the resistant cultivar (cv. Capitol) in response to Xcc. These results indicate that ZAR1 mediated the coordinated action of SA and JA synthesis and signaling to confirm ETI, whereas TAO1 enhanced the synthesis of SA through CAS and CBP60g to antagonize JA synthesis and signaling to cause disease susceptibility in the Brassica napus–Xcc pathosystem.

scholarly journals Identification and characterization of differentially expressed genes in Caenorhabditis elegans in response to pathogenic and nonpathogenic Stenotrophomonas maltophilia

2019 ◽  
Author(s):  
Leah J Radeke ◽  
Michael Herman
Keyword(s):  
Candidate Genes ◽  
Differentially Expressed Genes ◽  
Stenotrophomonas Maltophilia ◽  
Defense Mechanisms ◽  
Virulent Strain ◽  
Differentially Expressed ◽  
Transcriptional Responses ◽  
Transcriptomic Response ◽  
C Elegans ◽  
Realistic Interaction

Abstract Background: Stenotrophomonas maltophilia is an emerging nosocomial pathogen that causes infection in immunocompromised patients. S. maltophilia isolates are genetically diverse, contain diverse virulence factors, and are variably pathogenic within several host species. Members of the Stenotrophomonas genus are part of the native microbiome of C. elegans , being found in greater relative abundance within the worm than its environment, suggesting that these bacteria accumulate within C. elegans . Thus, study of the C. elegans-Stenotrophomonas interaction is of both medical and ecological significance. To identify host defense mechanisms, we analyzed the C. elegans transcriptomic response to S. maltophilia strains of varying pathogenicity: K279a, an avirulent clinical isolate, JCMS, a virulent strain isolated in association with soil nematodes near Manhattan, KS, and JV3, an even more virulent environmental isolate. Results: Overall, we found 145 genes that are commonly differentially expressed in response to pathogenic S. maltophilia strains, 89% of which are upregulated, with many even further upregulated in response to JV3 as compared to JCMS. There are many more JV3-specific differentially expressed genes (225, 11% upregulated) than JCMS-specific differentially expressed genes (14, 86% upregulated), suggesting JV3 has unique pathogenic mechanisms that could explain its increased virulence. We used connectivity within a gene network model to choose pathogen-specific and strain-specific differentially expressed candidate genes for functional analysis. Mutations in 13 of 22 candidate genes caused significant differences in C. elegans survival in response to at least one S. maltophilia strain, although not always the strain that induced differential expression, suggesting a dynamic response to varying levels of pathogenicity. Conclusions: Variation in observed pathogenicity and differences in host transcriptional responses to S. maltophilia strains reveal that strain-specific mechanisms play important roles in S. maltophilia pathogenesis. Furthermore, utilizing bacteria closely related to strains found in C. elegans natural environment provides a more realistic interaction for understanding host-pathogen response.

scholarly journals Characterization of human FDCs reveals regulation of T cells and antigen presentation to B cells

2021 ◽  
Vol 218 (10) ◽  
Author(s):  
Balthasar A. Heesters ◽  
Kyah van Megesen ◽  
Ilhan Tomris ◽  
Robert P. de Vries ◽  
Giuliana Magri ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Intimate Contact ◽  
Expression Of Genes ◽  
T Cell Regulation ◽  
Native Antigen ◽  
Reticular Cells ◽  
Molecular Patterns

Stromal-derived follicular dendritic cells (FDCs) are essential for germinal centers (GCs), the site where B cells maturate their antibodies. FDCs present native antigen to B cells and maintain a CXCL13 gradient to form the B cell follicle. Yet despite their essential role, the transcriptome of human FDCs remains undefined. Using single-cell RNA sequencing and microarray, we provided the transcriptome of these enigmatic cells as a comprehensive resource. Key genes were validated by flow cytometry and microscopy. Surprisingly, marginal reticular cells (MRCs) rather than FDCs expressed B cell activating factor (BAFF). Furthermore, we found that human FDCs expressed TLR4 and can alter antigen availability in response to pathogen-associated molecular patterns (PAMPs). High expression of PD-L1 and PD-L2 on FDCs activated PD1 on T cells. In addition, we found expression of genes related to T cell regulation, such as HLA-DRA, CD40, and others. These data suggest intimate contact between human FDCs and T cells.

scholarly journals The Effect of Transcription Factor MYB14 on Defense Mechanisms in Vitis quinquangularis-Pingyi

2020 ◽  
Vol 21 (3) ◽  
pp. 706 ◽  
Author(s):  
Yangyang Luo ◽  
Qingyang Wang ◽  
Ru Bai ◽  
Ruixiang Li ◽  
Lu Chen ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Nicotiana Benthamiana ◽  
Defense Mechanisms ◽  
Qualitative Difference ◽  
Defense Responses ◽  
Molecular Pattern ◽  
Effector Triggered Immunity ◽  
Pathogen Associated Molecular Pattern ◽  
Basal Immunity ◽  
Stilbene Biosynthesis

In the current study, we identified a transcription factor, MYB14, from Chinese wild grape, Vitis quinquangularis-Pingyi (V. quinquangularis-PY), which could enhance the main stilbene contents and expression of stilbene biosynthesis genes (StSy/RS) by overexpression of VqMYB14. The promoter of VqMYB14 (pVqMYB14) was shown to be induced as part of both basal immunity (also called pathogen-associated molecular pattern (PAMP)-triggered immunity, PTI) and effector-triggered immunity (ETI), triggered by the elicitors flg22 and harpin, respectively. This was demonstrated by expression of pVqMYB14 in Nicotiana benthamiana and Vitis. We identified sequence differences, notably an 11 bp segment in pVqMYB14 that is important for the PTI/ETI, and particularly for the harpin-induced ETI response. In addition, we showed that activation of the MYB14 promoter correlates with differences in the expression of MYB14 and stilbene pattern induced by flg22 and harpin. An experimental model of upstream signaling in V. quinquangularis-PY is presented, where early defense responses triggered by flg22 and harpin partially overlap, but where the timing and levels differ. This translates into a qualitative difference with respect to patterns of stilbene accumulation.

scholarly journals Identification of Genes in Xanthomonas campestris pv. vesicatoria Induced during Its Interaction with Tomato

2007 ◽  
Vol 189 (17) ◽  
pp. 6359-6371 ◽  
Author(s):  
Dafna Tamir-Ariel ◽  
Naama Navon ◽  
Saul Burdman
Keyword(s):  
Xanthomonas Campestris ◽  
Disease Process ◽  
In Planta ◽  
Gene Encoding ◽  
Host Interaction ◽  
Citrate Transporter ◽  
Knockout Mutants ◽  
Bacterial Spot Disease

ABSTRACT Xanthomonas campestris pv. vesicatoria is the causal agent of bacterial spot disease of tomato and pepper. The disease process is interactive and very intricate and involves a plethora of genes in the pathogen and in the host. In the pathogen, different genes are activated in response to the changing environment to enable it to survive, adapt, evade host defenses, propagate, and damage the host. To understand the disease process, it is imperative to broaden our understanding of the gene machinery that participates in it, and the most reliable way is to identify these genes in vivo. Here, we have adapted a recombinase-based in vivo expression technology (RIVET) to study the genes activated in X. campestris pv. vesicatoria during its interaction with one of its hosts, tomato. This is the first study that demonstrates the feasibility of this approach for identifying in vivo induced genes in a plant pathogen. RIVET revealed 61 unique X. campestris pv. vesicatoria genes or operons that delineate a picture of the different processes involved in the pathogen-host interaction. To further explore the role of some of these genes, we generated knockout mutants for 13 genes and characterized their ability to grow in planta and to cause disease symptoms. This analysis revealed several genes that may be important for the interaction of the pathogen with its host, including a citH homologue gene, encoding a citrate transporter, which was shown to be required for wild-type levels of virulence.

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