Molecular Dialog Between Parasitic Plants and Their Hosts

2019 ◽  
Vol 57 (1) ◽  
pp. 279-299 ◽  
Author(s):  
Christopher R. Clarke ◽  
Michael P. Timko ◽  
John I. Yoder ◽  
Michael J. Axtell ◽  
James H. Westwood
Keyword(s):  
Immune Responses ◽  
Agricultural Production ◽  
Host Plants ◽  
Plant Pathogens ◽  
Molecular Mechanisms ◽  
Parasitic Plants ◽  
Transcriptomic Data ◽  
Plant Parasitism ◽  
Body Of Knowledge ◽  
Plant Pathogen Interactions

Parasitic plants steal sugars, water, and other nutrients from host plants through a haustorial connection. Several species of parasitic plants such as witchweeds ( Striga spp.) and broomrapes ( Orobanche and Phelipanche spp.) are major biotic constraints to agricultural production. Parasitic plants are understudied compared with other major classes of plant pathogens, but the recent availability of genomic and transcriptomic data has accelerated the rate of discovery of the molecular mechanisms underpinning plant parasitism. Here, we review the current body of knowledge of how parasitic plants sense host plants, germinate, form parasitic haustorial connections, and suppress host plant immune responses. Additionally, we assess whether parasitic plants fit within the current paradigms used to understand the molecular mechanisms of microbial plant–pathogen interactions. Finally, we discuss challenges facing parasitic plant research and propose the most urgent questions that need to be answered to advance our understanding of plant parasitism.

scholarly journals Search for Resistant Genotypes to Cuscuta campestris Infection in Two Legume Species, Vicia sativa and Vicia ervilia

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 738
Author(s):  
Eva María Córdoba ◽  
Mónica Fernández-Aparicio ◽  
Clara Isabel González-Verdejo ◽  
Carmela López-Grau ◽  
María del Valle Muñoz-Muñoz ◽  
...  
Keyword(s):  
Agricultural Production ◽  
Host Plants ◽  
Resistance Breeding ◽  
Parasitic Plants ◽  
Vicia Sativa ◽  
Common Vetch ◽  
Germplasm Collections ◽  
Bitter Vetch ◽  
Cuscuta Campestris ◽  
Resistant Genotypes

The dodders (Cuscuta spp.) are parasitic plants that feed on the stems of their host plants. Cuscuta campestris is one of the most damaging parasitic plants for the worldwide agricultural production of broad-leaved crops. Its control is limited or non-existent, therefore resistance breeding is the best alternative both economically and environmentally. Common vetch (Vicia sativa) and bitter vetch (Vicia ervilia) are highly susceptible to C. campestris, but no resistant genotypes have been identified. Thus, the aim of this study was to identify in V. sativa and V.ervilia germplasm collections genotypes resistant to C. campestris infection for use in combating this parasitic plant. Three greenhouse screening were conducted to: (1) identify resistant responses in a collection of 154 accessions of bitter vetch and a collection of 135 accessions of common vetch genotypes against infection of C. campestris; (2) confirm the resistant response identified in common vetch accessions; and (3) characterize the effect of C. campestris infection on biomass of V. sativa resistant and susceptible accessions. Most common vetch and bitter vetch genotypes tested were susceptible to C. campestris. However, the V. sativa genotype Vs.1 exhibited high resistance. The resistant phenotype was characterized by a delay in the development of C. campestris posthaustorial growth and a darkening resembling a hypersensitive-like response at the penetration site. The resistant mechanism was effective in limiting the growth of C. campestris as the ratio of parasite/host shoot dry biomass was more significantly reduced than the rest of the accessions. To the best or our knowledge, this is the first identification of Cuscuta resistance in V. sativa genotypes.

scholarly journals Tandem protein kinases emerge as new regulators of plant immunity

2021 ◽  
Author(s):  
Valentyna Klymiuk ◽  
Gitta Coaker ◽  
Tzion Fahima ◽  
Curtis Pozniak
Keyword(s):  
Immune Responses ◽  
Host Plants ◽  
Current Knowledge ◽  
Plant Immunity ◽  
Susceptible Host ◽  
Future Studies ◽  
Receptor Proteins ◽  
Pathogen Effectors ◽  
Intracellular Proteins ◽  
Plant Pathogen Interactions

Plant-pathogen interactions result in disease development in a susceptible host. Plants actively resist pathogens via a complex immune system comprised of both surface-localized receptors that sense the extracellular space as well as intracellular receptors recognizing pathogen effectors. To date, the majority of cloned resistance genes encode intracellular nucleotide-binding leucine-rich repeat (NLR) receptor proteins. Recent discoveries have revealed Tandem Kinase Proteins (TKPs) as another important family of intracellular proteins involved in plant immune responses. Five TKP genes, barley Rpg1 and wheat WTK1 (Yr15), WTK2 (Sr60), WTK3 (Pm24), and WTK4 protect against devastating fungal diseases. Moreover, a large diversity and numerous putative TKPs exist across the plant kingdom. This review explores our current knowledge of TKPs and serves as a basis for future studies that aim to develop and exploit a deeper understanding of innate plant immunity receptor proteins.

scholarly journals Trick or Treat: Microbial Pathogens Evolved Apoplastic Effectors Modulating Plant Susceptibility to Infection

2018 ◽  
Vol 31 (1) ◽  
pp. 6-12 ◽  
Author(s):  
Yan Wang ◽  
Yuanchao Wang
Keyword(s):  
Immune Responses ◽  
Plant Pathogen ◽  
Plant Pathogens ◽  
Plant Cell Wall ◽  
Effector Proteins ◽  
Microbial Pathogens ◽  
Susceptibility To Infection ◽  
Plant Pathogen Interactions ◽  
Harsh Conditions ◽  
Plant Susceptibility

The apoplastic space between the plant cell wall and the plasma membrane constitutes a major battleground for plant-pathogen interactions. To survive in harsh conditions in the plant apoplast, pathogens must cope with various immune responses. During infection, plant pathogens secrete an arsenal of effector proteins into the apoplast milieu, some of which are detected by the plant surveillance system and, thus, activate plant innate immunity. Effectors that evade plant perception act in modulating plant apoplast immunity to favor successful pathogen infection. The concerted actions of apoplastic effectors often determine the outcomes of plant-pathogen interactions. In this review, we summarize current advances on the understanding of apoplastic effectors and highlight the strategies employed by pathogens to counter host apoplastic defense.

Arabidopsis thaliana as a model plant to study host-Meloidogyne graminicola interactions

Nematology ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 1015-1024
Author(s):  
Qiuling Huang ◽  
Handa Song ◽  
Borong Lin ◽  
Xiaodan Zheng ◽  
Wenjun Wang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Host Plants ◽  
Molecular Mechanisms ◽  
Root Surface ◽  
Broad Host Range ◽  
Meloidogyne Graminicola ◽  
Model Plant ◽  
Defence Genes ◽  
Significant Difference ◽  
Plant Pathogen Interactions

Summary The use of Arabidopsis thaliana as a model plant increased the rate of molecular discoveries of plant-pathogen interactions. Although Meloidogyne graminicola has a relatively broad host range, it is not known whether it can infect A. thaliana. In this study, we showed that M. graminicola is able to invade A. thaliana and complete its life cycle 12-14 days after invasion. No significant difference in the total number of nematodes inside roots of A. thaliana and rice, Oryza sativa, was found at 14 day after inoculation (dai). Significantly more galls were formed in A. thaliana roots compared to the numbers in O. sativa roots at 14 dai. Females laid egg masses on the A. thaliana root surface and a large number of hatched juveniles of the next generation were obtained from infected A. thaliana roots. In addition, the infection of M. graminicola can induce expression of A. thaliana basal defence genes, such as AtMYB51, AtWRKY11, AtPR1 and AtFRK1, at 24 h after inoculation. Therefore, A. thaliana can be considered as a suitable host to study host-M. graminicola interactions and to understand the molecular mechanisms developed by M. graminicola to infect its dicotyledonous host plants. In addition, our results also showed that a delayed development of M. graminicola occurred in A. thaliana compared to O. sativa, and a higher proportion of empty galls appeared in A. thaliana roots than in O. sativa roots, suggesting A. thaliana is a less optimal host than rice.

Two interacting transcriptional coactivators cooperatively control plant immune responses

2021 ◽  
Author(s):  
HUAN CHEN ◽  
Min Li ◽  
Guang Qi ◽  
Ming Zhao ◽  
Longyu Liu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Molecular Mechanisms ◽  
Control Plant ◽  
Transcriptional Coactivator ◽  
Pr Genes ◽  
Genetic Studies ◽  
Transactivation Domains ◽  
Transcriptional Reprogramming ◽  
Pathogenesis Related ◽  
Plant Pathogen Interactions

The phytohormone salicylic acid (SA) plays a pivotal role in plant defense against biotrophic and hemibiotrophic pathogens. Genetic studies have identified NPR1 and EDS1 as two central hubs in plant local and systemic immunity. However, it is unclear how NPR1 orchestrates gene regulation and whether EDS1 directly participates in transcriptional reprogramming. Here we show that NPR1 and EDS1 synergistically activate Pathogenesis-Related (PR) genes and plant defenses by forming a protein complex and co-opting with Mediator. In particular, we discover that EDS1 functions as an autonomous transcriptional coactivator with intrinsic transactivation domains and physically interacts with the CDK8 subunit of Mediator. Upon SA induction, EDS1 is directly recruited by NPR1 onto the PR1 promoter via physical NPR1-EDS1 interactions, thereby potentiating PR1 activation. We further demonstrate that EDS1 stabilizes NPR1 protein and NPR1 transcriptionally upregulates EDS1 in plant-pathogen interactions. Our results reveal an elegant interplay of key coactivators with Mediator and elucidate novel molecular mechanisms for activating transcription during immune responses.

ADDRESSING THE ISSUE OF СOVID-19, SARS-COV-2 VIRUS AND THE DISEASE

2020 ◽  
Vol 99 (6) ◽  
pp. 15-31
Author(s):  
A.A. Korenkova ◽  
◽  
E.M. Mayorova ◽  
V.V. Bahmetjev ◽  
M.V. Tretyak ◽  
...  
Keyword(s):  
Public Health ◽  
Immune Responses ◽  
Molecular Mechanisms ◽  
Herd Immunity ◽  
Significant Problem ◽  
Prevention Measures ◽  
Optimal Therapy ◽  
The World ◽  
Public Health Challenge ◽  
Coronavirus Infection

The new coronavirus infection has posed a major public health challenge around the world, but new data on the disease raises more questions than answers. The lack of optimal therapy is a significant problem. The article examines the molecular mechanisms of SARS-CoV-2 infection and the pathogenesis of COVID-19, special attention is paid to features of pathological processes and immune responses in children. COVID-19 leads to a wide diversity of negative outcomes, many of which can persist for at least months. Many of the consequences have yet to be identified. SARS-CoV-2 may provoke autoimmune reactions. Reinfection, herd immunity, vaccines and other prevention measures are also discussed in this review.

scholarly journals Human fetal liver MSCs are more effective than adult bone marrow MSCs for their immunosuppressive, immunomodulatory, and Foxp3+ T reg induction capacity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yi Yu ◽  
Alejandra Vargas Valderrama ◽  
Zhongchao Han ◽  
Georges Uzan ◽  
Sina Naserian ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Immune Responses ◽  
Molecular Mechanisms ◽  
Fetal Liver ◽  
Cytotoxic T Cells ◽  
Cell Contact ◽  
Adult Bone Marrow ◽  
Adult Bone

Abstract Background Mesenchymal stem cells (MSCs) exhibit active abilities to suppress or modulate deleterious immune responses by various molecular mechanisms. These cells are the subject of major translational efforts as cellular therapies for immune-related diseases and transplantations. Plenty of preclinical studies and clinical trials employing MSCs have shown promising safety and efficacy outcomes and also shed light on the modifications in the frequency and function of regulatory T cells (T regs). Nevertheless, the mechanisms underlying these observations are not well known. Direct cell contact, soluble factor production, and turning antigen-presenting cells into tolerogenic phenotypes, have been proposed to be among possible mechanisms by which MSCs produce an immunomodulatory environment for T reg expansion and activity. We and others demonstrated that adult bone marrow (BM)-MSCs suppress adaptive immune responses directly by inhibiting the proliferation of CD4+ helper and CD8+ cytotoxic T cells but also indirectly through the induction of T regs. In parallel, we demonstrated that fetal liver (FL)-MSCs demonstrates much longer-lasting immunomodulatory properties compared to BM-MSCs, by inhibiting directly the proliferation and activation of CD4+ and CD8+ T cells. Therefore, we investigated if FL-MSCs exert their strong immunosuppressive effect also indirectly through induction of T regs. Methods MSCs were obtained from FL and adult BM and characterized according to their surface antigen expression, their multilineage differentiation, and their proliferation potential. Using different in vitro combinations, we performed co-cultures of FL- or BM-MSCs and murine CD3+CD25−T cells to investigate immunosuppressive effects of MSCs on T cells and to quantify their capacity to induce functional T regs. Results We demonstrated that although both types of MSC display similar cell surface phenotypic profile and differentiation capacity, FL-MSCs have significantly higher proliferative capacity and ability to suppress both CD4+ and CD8+ murine T cell proliferation and to modulate them towards less active phenotypes than adult BM-MSCs. Moreover, their substantial suppressive effect was associated with an outstanding increase of functional CD4+CD25+Foxp3+ T regs compared to BM-MSCs. Conclusions These results highlight the immunosuppressive activity of FL-MSCs on T cells and show for the first time that one of the main immunoregulatory mechanisms of FL-MSCs passes through active and functional T reg induction.

scholarly journals Cardiac Cell Therapy: Insights into the Mechanisms of Tissue Repair

2021 ◽  
Vol 22 (3) ◽  
pp. 1201
Author(s):  
Hsuan Peng ◽  
Kazuhiro Shindo ◽  
Renée R. Donahue ◽  
Ahmed Abdel-Latif
Keyword(s):  
Stem Cell ◽  
Immune Responses ◽  
Tissue Repair ◽  
Molecular Mechanisms ◽  
Clinical Evidence ◽  
Current Knowledge ◽  
Cell Delivery ◽  
Cardiac Cell Therapy ◽  
Stem Cell Treatment

Stem cell-based cardiac therapies have been extensively studied in recent years. However, the efficacy of cell delivery, engraftment, and differentiation post-transplant remain continuous challenges and represent opportunities to further refine our current strategies. Despite limited long-term cardiac retention, stem cell treatment leads to sustained cardiac benefit following myocardial infarction (MI). This review summarizes the current knowledge on stem cell based cardiac immunomodulation by highlighting the cellular and molecular mechanisms of different immune responses to mesenchymal stem cells (MSCs) and their secretory factors. This review also addresses the clinical evidence in the field.

scholarly journals TRAF6-IRF5 kinetics, TRIF, and biophysical factors drive synergistic innate responses to particle-mediated MPLA-CpG co-presentation

2021 ◽  
Vol 7 (3) ◽  
pp. eabd4235
Author(s):  
P. Pradhan ◽  
R. Toy ◽  
N. Jhita ◽  
A. Atalis ◽  
B. Pandey ◽  
...  
Keyword(s):  
Immune Responses ◽  
Molecular Mechanisms ◽  
Lipid A ◽  
Critical Role ◽  
Mouse Bone Marrow ◽  
Biophysical Properties ◽  
Gm Csf ◽  
Monophosphoryl Lipid A ◽  
Integrated Response ◽  
Particulate Carriers

Innate immune responses to pathogens are driven by co-presentation of multiple pathogen-associated molecular patterns (PAMPs). Combinations of PAMPs can trigger synergistic immune responses, but the underlying molecular mechanisms of synergy are poorly understood. Here, we used synthetic particulate carriers co-loaded with monophosphoryl lipid A (MPLA) and CpG as pathogen-like particles (PLPs) to dissect the signaling pathways responsible for dual adjuvant immune responses. PLP-based co-delivery of MPLA and CpG to GM-CSF–driven mouse bone marrow–derived antigen-presenting cells (BM-APCs) elicited synergistic interferon-β (IFN-β) and interleukin-12p70 (IL-12p70) responses, which were strongly influenced by the biophysical properties of PLPs. Mechanistically, we found that MyD88 and interferon regulatory factor 5 (IRF5) were necessary for IFN-β and IL-12p70 production, while TRIF signaling was required for the synergistic response. Both the kinetics and magnitude of downstream TRAF6 and IRF5 signaling drove the synergy. These results identify the key mechanisms of synergistic Toll-like receptor 4 (TLR4)–TLR9 co-signaling in mouse BM-APCs and underscore the critical role of signaling kinetics and biophysical properties on the integrated response to combination adjuvants.

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