scholarly journals Pattern Recognition Receptors—Versatile Genetic Tools for Engineering Broad-Spectrum Disease Resistance in Crops

Agronomy ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 134 ◽  
Author(s):  
Stefanie Ranf
Keyword(s):  
Pattern Recognition ◽  
Disease Resistance ◽  
Broad Spectrum ◽  
Defense Mechanisms ◽  
Control Plant ◽  
Pattern Recognition Receptors ◽  
Plant Diseases ◽  
Crop Species ◽  
Natural Defense ◽  
Plant Disease Management

Infestations of crop plants with pathogens pose a major threat to global food supply. Exploiting plant defense mechanisms to produce disease-resistant crop varieties is an important strategy to control plant diseases in modern plant breeding and can greatly reduce the application of agrochemicals. The discovery of different types of immune receptors and a detailed understanding of their activation and regulation mechanisms in the last decades has paved the way for the deployment of these central plant immune components for genetic plant disease management. This review will focus on a particular class of immune sensors, termed pattern recognition receptors (PRRs), that activate a defense program termed pattern-triggered immunity (PTI) and outline their potential to provide broad-spectrum and potentially durable disease resistance in various crop species—simply by providing plants with enhanced capacities to detect invaders and to rapidly launch their natural defense program.

scholarly journals Heterologous expression of the immune receptorEFRinMedicago truncatulareduces pathogenic infection, but not rhizobial symbiosis

2017 ◽  
Author(s):  
Sebastian Pfeilmeier ◽  
Jeoffrey George ◽  
Alice Morel ◽  
Sonali Roy ◽  
Matthew Smoker ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Disease Resistance ◽  
Plant Species ◽  
Broad Spectrum ◽  
Positive Impact ◽  
Early Stage ◽  
Bacterial Pathogen ◽  
Pattern Recognition Receptors ◽  
Infection Process ◽  
Biotechnological Approach

AbstractInterfamily transfer of plant pattern recognition receptors (PRRs) represents a promising biotechnological approach to engineer broad-spectrum, and potentially durable, disease resistance in crops. It is however unclear whether new recognition specificities to given pathogen-associated molecular patterns (PAMPs) affect the interaction of the recipient plant with beneficial microbes. To test this in a direct reductionist approach, we transferred theBrassicaceae-specific PRR ELONGATION FACTOR-THERMO UNSTABLE RECEPTOR (EFR) fromArabidopsis thalianato the legumeMedicago truncatula, conferring recognition of the bacterial EF-Tu protein. ConstitutiveEFRexpression led to EFR accumulation and activation of immune responses upon treatment with the EF-Tu-derived elf18 peptide in leaves and roots. The interaction ofM. truncatulawith the bacterial symbiontSinorhizobium melilotiis characterized by the formation of root nodules that fix atmospheric nitrogen. Although nodule numbers were slightly reduced at an early stage of the infection inEFR-Medicagowhen compared to control lines, nodulation was similar in all lines at later stages. Furthermore, nodule colonization by rhizobia, and nitrogen fixation were not compromised byEFRexpression. Importantly, theM. truncatulalines expressingEFRwere substantially more resistant to the root bacterial pathogenRalstonia solanacearum. Our data suggest that the transfer of EFR toM. truncatuladoes not impede root nodule symbiosis, but has a positive impact on disease resistance against a bacterial pathogen. In addition, our results indicate thatRhizobiumcan either avoid PAMP recognition during the infection process, or is able to actively suppress immune signaling.Significance StatementCrop engineering helps reducing the economic and environmental costs of plant disease. The genetic transfer of immune receptors across plant species is a promising biotechnological approach to increase disease resistance. Surface-localized pattern-recognition receptors (PRRs), which detect conserved characteristic microbial features, are functional in heterologous taxonomically-diverse plant species, and confer broad-spectrum disease resistance. It was unclear whether PRR transfer negatively impacts the association of the recipient plants with symbiotic microbes. Here, we show that a legume engineered with a novel PRR recognizing a conserved bacterial protein becomes more resistant to an important bacterial pathogen without significant impact on nitrogen-fixing symbiosis with rhizobia. This finding is of particular relevance as attempts to transfer this important symbiosis into non-legume plants are ongoing.

scholarly journals Optimizing Plant Disease Management in Agricultural Ecosystems Through Rational In-Crop Diversification

2021 ◽  
Vol 12 ◽  
Author(s):  
Yan-Ping Wang ◽  
Zhe-Chao Pan ◽  
Li-Na Yang ◽  
Jeremy J. Burdon ◽  
Hanna Friberg ◽  
...  
Keyword(s):  
Late Blight ◽  
Host Resistance ◽  
Control Plant ◽  
Late Blight Resistance ◽  
Plant Diseases ◽  
Crop Diversification ◽  
Agricultural Ecosystems ◽  
Potato Varieties ◽  
Plant Disease Management ◽  
Disease Epidemics

Biodiversity plays multifaceted roles in societal development and ecological sustainability. In agricultural ecosystems, using biodiversity to mitigate plant diseases has received renewed attention in recent years but our knowledge of the best ways of using biodiversity to control plant diseases is still incomplete. In term of in-crop diversification, it is not clear how genetic diversity per se in host populations interacts with identifiable resistance and other functional traits of component genotypes to mitigate disease epidemics and what is the best way of structuring mixture populations. In this study, we created a series of host populations by mixing different numbers of potato varieties showing different late blight resistance levels in different proportions. The amount of naturally occurring late blight disease in the mixture populations was recorded weekly during the potato growing seasons. The percentage of disease reduction (PDR) in the mixture populations was calculated by comparing their observed late blight levels relative to that expected when they were planted in pure stands. We found that PDR in the mixtures increased as the number of varieties and the difference in host resistance (DHR) between the component varieties increased. However, the level of host resistance in the potato varieties had little impact on PDR. In mixtures involving two varieties, the optimum proportion of component varieties for the best PDR depended on their DHR, with an increasing skewness to one of the component varieties as the DHR between the component varieties increased. These results indicate that mixing crop varieties can significantly reduce disease epidemics in the field. To achieve the best disease mitigation, growers should include as many varieties as possible in mixtures or, if only two component mixtures are possible, increase DHR among the component varieties.

scholarly journals Pattern Recognition Receptors and Cytokines inMycobacterium tuberculosisInfection—The Double-Edged Sword?

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Md. Murad Hossain ◽  
Mohd-Nor Norazmi
Keyword(s):  
Pattern Recognition ◽  
Innate Immunity ◽  
Defense Mechanisms ◽  
Defense Mechanism ◽  
Adaptive Immune Response ◽  
Protective Role ◽  
Pattern Recognition Receptors ◽  
Immune Defense ◽  
Innate Immune ◽  
Intercellular Adhesion Molecule

Tuberculosis, an infectious disease caused byMycobacterium tuberculosis(Mtb), remains a major cause of human death worldwide. Innate immunity provides host defense against Mtb. Phagocytosis, characterized by recognition of Mtb by macrophages and dendritic cells (DCs), is the first step of the innate immune defense mechanism. The recognition of Mtb is mediated by pattern recognition receptors (PRRs), expressed on innate immune cells, including toll-like receptors (TLRs), complement receptors, nucleotide oligomerization domain like receptors, dendritic cell-specific intercellular adhesion molecule grabbing nonintegrin (DC-SIGN), mannose receptors, CD14 receptors, scavenger receptors, and FCγreceptors. Interaction of mycobacterial ligands with PRRs leads macrophages and DCs to secrete selected cytokines, which in turn induce interferon-γ- (IFNγ-) dominated immunity. IFNγand other cytokines like tumor necrosis factor-α(TNFα) regulate mycobacterial growth, granuloma formation, and initiation of the adaptive immune response to Mtb and finally provide protection to the host. However, Mtb can evade destruction by antimicrobial defense mechanisms of the innate immune system as some components of the system may promote survival of the bacteria in these cells and facilitate pathogenesis. Thus, although innate immunity components generally play a protective role against Mtb, they may also facilitate Mtb survival. The involvement of selected PRRs and cytokines on these seemingly contradictory roles is discussed.

scholarly journals RNA Interference: A Versatile Tool for Functional Genomics and Unraveling the Genes Required for Viral Disease Resistance in Plants

2019 ◽  
pp. 1-20 ◽  
Author(s):  
Tushar Ranjan ◽  
Namaste Kumari ◽  
Sangita Sahni ◽  
Bishun Deo Prasad
Keyword(s):  
Disease Resistance ◽  
Gene Silencing ◽  
Defense Mechanisms ◽  
Reverse Genetics ◽  
Viral Disease ◽  
Virus Induced Gene Silencing ◽  
Advantages And Disadvantages ◽  
Natural Defense ◽  
Versatile Tool ◽  
Plant Genes

Virus-induced gene silencing (VIGS) is a powerful reverse genetics technology used to unravel the functions of genes. It uses viruses as vectors to carry targeted plant genes. The virus vector is used to induce RNA-mediated silencing of a gene or genes in the host plant. The process of silencing is triggered by dsRNA molecules, the mechanism is explained in this chapter. Over the years a large number of viruses have been modified for use as VIGS vectors and a list of these vectors is also included. As the name suggests, virus-induced gene silencing uses the host plant’s natural defense mechanisms against viral infection to silence plant genes. VIGS is methodologically simple and is widely used to determine gene functions, including disease resistance, abiotic stress, biosynthesis of secondary metabolites and signal transduction pathways. Here, we made an attempt to describe the basic underlying molecular mechanism of VIGS, the methodology and various experimental requirements, as well as its advantages and disadvantages. Finally, we discuss the future prospects of VIGS in relation to CRISPR/Cas9 technology. Besides using it to overexpress or silence genes, VIGS has emerged as the preferred delivery system for the cutting edge CRISPR/Cas9 genome editing technology.

scholarly journals Agrometeorology and plant disease management: a happy marriage

2008 ◽  
Vol 65 (spe) ◽  
pp. 71-75 ◽  
Author(s):  
Terry James Gillespie ◽  
Paulo Cesar Sentelhas
Keyword(s):  
Disease Management ◽  
Plant Disease ◽  
Control Plant ◽  
Disease Outbreaks ◽  
Plant Diseases ◽  
Leaf Wetness ◽  
Happy Marriage ◽  
Plant Disease Management ◽  
Near Future ◽  
Weather Models

Many plant disease outbreaks are triggered by suitably warm temperatures during periods of leaf wetness. Measurements or estimations of leaf wetness duration provided by Agrometeorologists have allowed Plant Pathologists to devise weather timed spray schemes which often reduce the number of sprays required to control plant diseases, thus lowering costs and benefitting the environment. In the near future, tools such as numerical weather models with small grid spacings, and improved weather radar, are expected to reduce the need for tight networks of surface observations. The weather models will also provide growers with forecast warnings of potential upcoming disease outbreaks, which will further enhance the contribution of agrometeorology to plant disease management.

scholarly journals Loss of function of a DMR6 ortholog in tomato confers broad-spectrum disease resistance

2021 ◽  
Vol 118 (27) ◽  
pp. e2026152118
Author(s):  
Daniela Paula de Toledo Thomazella ◽  
Kyungyong Seong ◽  
Rebecca Mackelprang ◽  
Douglas Dahlbeck ◽  
Yu Geng ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Broad Spectrum ◽  
Transcriptional Activation ◽  
Plant Diseases ◽  
R Genes ◽  
Loss Of Function ◽  
Pathogen Infection ◽  
Promising Alternative ◽  
Enzymatic Function ◽  
Fine Tune

Plant diseases are among the major causes of crop yield losses around the world. To confer disease resistance, conventional breeding relies on the deployment of single resistance (R) genes. However, this strategy has been easily overcome by constantly evolving pathogens. Disabling susceptibility (S) genes is a promising alternative to R genes in breeding programs, as it usually offers durable and broad-spectrum disease resistance. In Arabidopsis, the S gene DMR6 (AtDMR6) encodes an enzyme identified as a susceptibility factor to bacterial and oomycete pathogens. Here, we present a model-to-crop translational work in which we characterize two AtDMR6 orthologs in tomato, SlDMR6-1 and SlDMR6-2. We show that SlDMR6-1, but not SlDMR6-2, is up-regulated by pathogen infection. In agreement, Sldmr6-1 mutants display enhanced resistance against different classes of pathogens, such as bacteria, oomycete, and fungi. Notably, disease resistance correlates with increased salicylic acid (SA) levels and transcriptional activation of immune responses. Furthermore, we demonstrate that SlDMR6-1 and SlDMR6-2 display SA-5 hydroxylase activity, thus contributing to the elucidation of the enzymatic function of DMR6. We then propose that SlDMR6 duplication in tomato resulted in subsequent subfunctionalization, in which SlDMR6-2 specialized in balancing SA levels in flowers/fruits, while SlDMR6-1 conserved the ability to fine-tune SA levels during pathogen infection of the plant vegetative tissues. Overall, this work not only corroborates a mechanism underlying SA homeostasis in plants, but also presents a promising strategy for engineering broad-spectrum and durable disease resistance in crops.

scholarly journals A novel cross talk of AtRAV1, an ethylene responsive transcription factor with MAP kinases imparts broad spectrum disease resistance in plants

2020 ◽  
Author(s):  
Ravindra Kumar Chandan ◽  
Rahul Kumar ◽  
Durga Madhab Swain ◽  
Srayan Ghosh ◽  
Prakash Kumar Bhagat ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Broad Spectrum ◽  
Map Kinases ◽  
Plant Diseases ◽  
Virus Infections ◽  
Defense Genes ◽  
Enhanced Expression ◽  
Transgenic Lines ◽  
Diverse Plant Species ◽  
Tomato Leaf Curl

AbstractPlant diseases pose a serious threat to sustainable agriculture as controlling them in eco-friendly manner remains a challenge. In this study, we establish RAV1 as a master transcriptional regulator of defense genes in model plant Arabidopsis. The overexpression of AtRAV1 provided disease resistance against necrotrophic fungal pathogen (Rhizoctonia solani) infection in A. thaliana. The transgenic lines exhibited enhanced expression of several defense genes including mitogen associated protein kinases (MAPKs) and the amplitude of their expression was further enhanced upon pathogen infection. Conversely, the atrav1 mutant plants were unable to induce the expression of these defense genes and were highly susceptible to infection. Our data suggests that upon pathogen attack, AtRAV1 transcriptionally upregulate the expression of MAPKs (AtMPK3, AtMPK4 and AtMPK6) and AtMPK3 and AtMPK6 are essential for AtRAV1 mediated disease resistance. Further, we demonstrate that AtRAV1 is a phosphorylation target of AtMPK3 (but not AtMPK6) and the phospho-defective variants of AtRAV1 are unable to induce disease resistance in A. thaliana. Considering the presence of AtRAV1 orthologs in diverse plant species, we propose that they can be gainfully deployed to control economically important diseases. In deed we observe that overexpression of tomato ortholog of AtRAV1 (SlRAV1) provides broad spectrum disease resistance against bacterial (Ralstonia solanacearum), fungal (R. solani) and viral (Tomato leaf curl virus) infections in tomato.

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