Biotechnological Resources to Increase Disease-Resistance by Improving Plant Immunity: A Sustainable Approach to Save Cereal Crop Production

Plant diseases are globally causing substantial losses in staple crop production, undermining the urgent goal of a 60% increase needed to meet the food demand, a task made more challenging by the climate changes. Main consequences concern the reduction of food amount and quality. Crop diseases also compromise food safety due to the presence of pesticides and/or toxins. Nowadays, biotechnology represents our best resource both for protecting crop yield and for a science-based increased sustainability in agriculture. Over the last decades, agricultural biotechnologies have made important progress based on the diffusion of new, fast and efficient technologies, offering a broad spectrum of options for understanding plant molecular mechanisms and breeding. This knowledge is accelerating the identification of key resistance traits to be rapidly and efficiently transferred and applied in crop breeding programs. This review gathers examples of how disease resistance may be implemented in cereals by exploiting a combination of basic research derived knowledge with fast and precise genetic engineering techniques. Priming and/or boosting the immune system in crops represent a sustainable, rapid and effective way to save part of the global harvest currently lost to diseases and to prevent food contamination.

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

10.32747/2012.7597918.bard ◽

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.

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Gene-for-gene interactions are required for disease resistance mediated by virus transgene

Plant Protection Science ◽

10.17221/10349-pps ◽

2002 ◽

Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽

pp. 177-179

Author(s):

M. Ravelonandro

Keyword(s):

Disease Resistance ◽

Rna Interference ◽

Molecular Mechanisms ◽

Plant Viruses ◽

Economic Losses ◽

Gene Interactions ◽

Severe Damage ◽

Breeding Programs ◽

Pathogen Derived Resistance ◽

Potential Use

Plant viruses cause severe damage and significant economic losses to agriculture. Control of virus usually consist of the elimination of virus vectors (insects, nematodes, fungi, etc), improvement of the sanitary status of the propagation material, the use of resistance sources in breeding programs. The application of the pathogen-derived resistance strategy has opened new avenues to protect plants against viruses. Two molecular mechanisms seem to underlie the engineered protection, the virus transgene-derived protein and the transgene-RNA interference. A few examples that support the efficiencies of these two molecular mechanisms are reviewed here and discussed in light of the potential use of virusresistant transgenic plants in agriculture.

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Molecular mechanisms of host cell manipulation by plant pathogens

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314091980 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C801-C801

Author(s):

Richard Hughes ◽

Stuart King ◽

Abbas Maqbool ◽

Hazel McLellan ◽

Tolga Bozkurt ◽

...

Keyword(s):

Cell Death ◽

Crop Production ◽

Plant Pathogens ◽

Molecular Mechanisms ◽

Complex Structure ◽

Effector Proteins ◽

Plant Diseases ◽

Cell Manipulation ◽

Cell Physiology ◽

Structural Studies

An estimated 15% of global crop production is lost to pre-harvest disease every year. New ways to manage plant diseases are required. A mechanistic understanding of how plant pathogens re-program their hosts to enable colonisation may provide novel genetic or chemical opportunities to interfere with disease. One notorious plant parasite is the Irish potato famine pathogen Phytophthora infestans. This pathogen remains a considerable threat to potato/tomato crops today as the agent of late blight. Plant pathogens secrete effector proteins outside of and into plant cells to suppress host defences and manipulate cell physiology. Structural studies have provided insights into effector evolution and enabled experiments to probe function [1-3]. Crystal structures of 4 Phytophthora RXLR-type effectors, which are unrelated in primary sequence, revealed similarities in the fold of these proteins. This fold was proposed to act as a stable scaffold that supports diversification of effectors. Further, molecular modelling has enabled mapping of single-site variants responsible for specialisation of a Phytophthora Cystatin-like effector, revealing how effectors can adapt to new hosts after a "host jump". Structural studies describing how RXLR-effectors interact with host targets are lacking. We have used Y2H/co-IP studies to identify host proteins that interact with P. infestans effectors PexRD2 and PexRD54. PexRD2 interacts with MAPKKKe, a component of plant immune signalling pathways, and suppressed cell death activities of this protein. We used the structure of PexRD2 to design mutants that fail to interact with MAPKKKe, and no longer suppress cell-death activities. We found that PexRD54 interacts with potato homologues of the autophagy protein ATG8. We have obtained a crystal structure for PexRD54 in the presence of ATG8. We are now using X-ray scattering to verify the complex structure in solution prior to establishing the role of this interaction during infection.

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Elevating crop disease resistance with cloned genes

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2013.0087 ◽

2014 ◽

Vol 369 (1639) ◽

pp. 20130087 ◽

Cited By ~ 62

Author(s):

Jonathan D. G. Jones ◽

Kamil Witek ◽

Walter Verweij ◽

Florian Jupe ◽

David Cooke ◽

...

Keyword(s):

Disease Resistance ◽

Plant Disease Resistance ◽

Soil Compaction ◽

Crop Production ◽

Resistance Mechanisms ◽

Plant Diseases ◽

The Past ◽

Great Progress ◽

Crop Disease ◽

Made In

Essentially all plant species exhibit heritable genetic variation for resistance to a variety of plant diseases caused by fungi, bacteria, oomycetes or viruses. Disease losses in crop monocultures are already significant, and would be greater but for applications of disease-controlling agrichemicals. For sustainable intensification of crop production, we argue that disease control should as far as possible be achieved using genetics rather than using costly recurrent chemical sprays. The latter imply CO 2 emissions from diesel fuel and potential soil compaction from tractor journeys. Great progress has been made in the past 25 years in our understanding of the molecular basis of plant disease resistance mechanisms, and of how pathogens circumvent them. These insights can inform more sophisticated approaches to elevating disease resistance in crops that help us tip the evolutionary balance in favour of the crop and away from the pathogen. We illustrate this theme with an account of a genetically modified (GM) blight-resistant potato trial in Norwich, using the Rpi-vnt1.1 gene isolated from a wild relative of potato, Solanum venturii , and introduced by GM methods into the potato variety Desiree.

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Versatile Applications of the CRISPR/Cas Toolkit in Plant Pathology and Disease Management

Phytopathology ◽

10.1094/phyto-08-20-0322-ia ◽

2020 ◽

Author(s):

Matthew Wheatley ◽

Yinong Yang

Keyword(s):

Plant Pathology ◽

Disease Resistance ◽

Disease Management ◽

Plant Disease Resistance ◽

Crop Production ◽

Genome Engineering ◽

Population Control ◽

Basic Research ◽

Gene Drive ◽

Basic Study

New tools and advanced technologies have played key roles in facilitating basic research in plant pathology and practical approaches for disease management and crop health. Recently, the CRISPR/Cas (clustered regularly interspersed short palindromic repeats/CRISPR associated) system has emerged as a powerful and versatile tool for genome editing and other molecular applications. This review aims to introduce and highlight the CRISPR/Cas toolkit and its current and future impact on plant pathology and disease management. We will cover the rapidly expanding horizon of various CRISPR/Cas applications in the basic study of plant-pathogen interactions, genome engineering of plant disease resistance, and molecular diagnosis of diverse pathogens. Using the citrus greening disease as an example, various CRISPR/Cas-enabled strategies are presented to precisely edit the host genome for disease resistance, to rapidly detect the pathogen for disease management, and to potentially use gene drive for insect population control. At the cutting edge of nucleic acid manipulation and detection, the CRISPR/Cas toolkit will accelerate plant breeding and reshape crop production and disease management as we face the challenges in 21st century agriculture.

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Cell wall associated immunity in plants

Stress Biology ◽

10.1007/s44154-021-00003-4 ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Jiangxue Wan ◽

Min He ◽

Qingqing Hou ◽

Lijuan Zou ◽

Yihua Yang ◽

...

Keyword(s):

Immune Response ◽

Cell Wall ◽

Disease Resistance ◽

Plant Cell ◽

Plant Disease Resistance ◽

Plant Disease ◽

Plant Cell Wall ◽

Plant Immunity ◽

Signal Molecules ◽

Crop Breeding

AbstractThe plant cell wall is the first physical and defensive barrier against pathogens. The plant cell wall usually undergoes dynamic remodeling as an immune response to prevent infection by pathogens. In this review, we summarize advances on relationship between cell wall and immunity in plants. In particular, we outline current progresses regarding the regulation of the cell wall components, including cellulose, hemicellulose, pectin and lignin, on plant disease resistance. We also discuss the impacts of cell wall-derived cellodextrin, oligogalacturonic acid and xyloglucan/xylan oligosaccharides as potent elicitors or signal molecules to trigger plant immune response. We further propose future studies on dissecting the molecular regulation of cell wall on plant immunity, which have potentials in practical application of crop breeding aiming at improvement of plant disease resistance.

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Using Dynamic Changes of Chlorophyll Fluorescence in Arabidopsis thaliana to Evaluate Plant Immunity-Intensifying Bacillus spp. Strains

Phytopathology ◽

10.1094/phyto-02-19-0063-r ◽

2019 ◽

Vol 109 (9) ◽

pp. 1566-1576

Author(s):

Yi-Hsin Wang ◽

I-Ling Lai ◽

Jing-Lin Zheng ◽

Yi-Hsien Lin

Keyword(s):

Arabidopsis Thaliana ◽

Disease Resistance ◽

Chlorophyll Fluorescence ◽

Plant Immunity ◽

Soft Rot ◽

Defense Responses ◽

Plant Diseases ◽

Bacterial Soft Rot ◽

Dynamic Changes ◽

Carotovorum Subsp

The integral defense responses of plants triggered by the small molecules of plant pathogens are regarded as plant immunity. The pathogen-associated molecular pattern-triggered immunity (PTI) occurs on the recognition of a pathogen by receptors on plant cell surfaces as an infection begins. During the activation of PTI, the effectiveness of a plant’s photosynthetic system may be altered. In this study, chlorophyll fluorescence was used to assay the dynamic changes of PTI. When we used flg22Pst as an elicitor, we found that the photosynthetic electron transport rate (ETR) of Arabidopsis thaliana Col-0 was significantly decreased at 2, 4, and 24 h on treatment with a PTI-intensifying protein, plant ferredoxin-like protein (PFLP). In addition, this reduction in the photosynthetic ETR was also carried out with a PTI-intensifying Bacillus amyloliquefaciens strain, PMB05, on the induction of flg22Pst. The disease resistance against bacterial soft rot caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) was still enhanced by PMB05. Interestingly, among the eight tested Bacillus species strains, the PTI triggered by HrpNPcc from P. carotovorum subsp. carotovorum exhibited an ETR that was significantly decreased by PMB05. Furthermore, this decrease was consistent with rapid H2O2 generation and callose deposition triggered by HrpNPcc and the disease resistance against bacterial soft rot. Taken together, such results led us to conclude that the assay based on the ETR established in this study can be used as a model for evaluating the effectiveness of plant immunity-intensifying microbes for controlling plant diseases.

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Expression of the Human NAD(P)-Metabolizing Ectoenzyme CD38 Compromises Systemic Acquired Resistance in Arabidopsis

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-10-11-0278 ◽

2012 ◽

Vol 25 (9) ◽

pp. 1209-1218 ◽

Cited By ~ 15

Author(s):

Xudong Zhang ◽

Zhonglin Mou

Keyword(s):

Disease Resistance ◽

Molecular Mechanisms ◽

Systemic Acquired Resistance ◽

Plant Immunity ◽

Acquired Resistance ◽

Defense Gene Expression ◽

Signal Molecule ◽

Defense Gene ◽

P Concentration ◽

Extracellular Compartment

Plant systemic acquired resistance (SAR) is a long-lasting, broad-spectrum immune response that is mounted after primary pathogen infection. Although SAR has been extensively researched, the molecular mechanisms underlying its activation have not been completely understood. We have previously shown that the electron carrier NAD(P) leaks into the plant extracellular compartment upon pathogen attack and that exogenous NAD(P) activates defense gene expression and disease resistance in local treated leaves, suggesting that extracellular NAD(P) [eNAD(P)] might function as a signal molecule activating plant immune responses. To further establish the function of eNAD(P) in plant immunity, we tested the effect of exogenous NAD(P) on resistance gene-mediated hypersensitive response (HR) and SAR. We found that exogenous NAD(P) completely suppresses HR-mediated cell death but does not affect HR-mediated disease resistance. Local application of exogenous NAD(P) is unable to induce SAR in distal tissues, indicating that eNAD(P) is not a sufficient signal for SAR activation. Using transgenic Arabidopsis plants expressing the human NAD(P)-metabolizing ectoenzyme CD38, we demonstrated that altering eNAD(P) concentration or signaling compromises biological induction of SAR. This result suggests that eNAD(P) may play a critical signaling role in activation of SAR.

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A molecular roadmap to the plant immune system

Journal of Biological Chemistry ◽

10.1074/jbc.rev120.010852 ◽

2020 ◽

Vol 295 (44) ◽

pp. 14916-14935 ◽

Cited By ~ 2

Author(s):

Adam R. Bentham ◽

Juan Carlos De la Concepcion ◽

Nitika Mukhi ◽

Rafał Zdrzałek ◽

Markus Draeger ◽

...

Keyword(s):

Immune System ◽

Cell Surface ◽

Molecular Mechanisms ◽

Plant Immunity ◽

Plant Diseases ◽

Global Food Security ◽

Immune Receptors ◽

Plant Immune System ◽

Control Disease ◽

And Function

Plant diseases caused by pathogens and pests are a constant threat to global food security. Direct crop losses and the measures used to control disease (e.g. application of pesticides) have significant agricultural, economic, and societal impacts. Therefore, it is essential that we understand the molecular mechanisms of the plant immune system, a system that allows plants to resist attack from a wide variety of organisms ranging from viruses to insects. Here, we provide a roadmap to plant immunity, with a focus on cell-surface and intracellular immune receptors. We describe how these receptors perceive signatures of pathogens and pests and initiate immune pathways. We merge existing concepts with new insights gained from recent breakthroughs on the structure and function of plant immune receptors, which have generated a shift in our understanding of cell-surface and intracellular immunity and the interplay between the two. Finally, we use our current understanding of plant immunity as context to discuss the potential of engineering the plant immune system with the aim of bolstering plant defenses against disease.

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Getting the Most from the Host: How Pathogens Force Plants to Cooperate in Disease

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-04-10-0103 ◽

2010 ◽

Vol 23 (10) ◽

pp. 1253-1259 ◽

Cited By ~ 36

Author(s):

Sophie Hok ◽

Agnès Attard ◽

Harald Keller

Keyword(s):

Defense Mechanisms ◽

Crop Production ◽

Molecular Mechanisms ◽

Production Systems ◽

Crop Protection ◽

Pathogen Resistance ◽

Plant Diseases ◽

Pathogen Effectors ◽

Successful Infection ◽

Protection Strategies

Plant diseases caused by pathogenic microorganisms remain a major limitation in many crop production systems. Nonetheless, constitutive and inducible defense mechanisms render most plants inaccessible to pathogens, making disease an exception rather than a common outcome of plant-microbe interactions. Defense mechanisms and associated pathogen resistance were thus of key interest to many plant pathologists, and many of the molecular mechanisms underlying resistance have been elucidated over the last few decades. In recent years, the analysis of physiological and molecular determinants accounting for successful infection and eventual disease has become a topic of prime scientific interest. The hunt is now on for pathogen effectors subverting the host cell and for the plant compatibility functions manipulated by these effectors. An understanding of the molecular mechanisms underlying successful infection should make it possible to develop new crop protection strategies based on interference with compatibility to prevent disease. This review is addressing plant susceptibility and highlights a number of host processes that have been shown to be induced or subverted to facilitate infection. In particular, we focus on those processes that appear to be manipulated by filamentous fungal and oomycete pathogens.

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