scholarly journals Disarming the Host: Detoxification of Plant Defense Compounds During Fungal Necrotrophy

2021 ◽  
Vol 12 ◽  
Author(s):  
Nathaniel M. Westrick ◽  
Damon L. Smith ◽  
Mehdi Kabbage
Keyword(s):  
Plant Defense ◽  
Host Range ◽  
Fungal Pathogens ◽  
Enzymatic Catalysis ◽  
Live Cells ◽  
Defense Compounds ◽  
Fungal Host ◽  
Successful Infection ◽  
Multiple Pathogens ◽  
Toxin Sequestration

While fungal biotrophs are dependent on successfully suppressing/subverting host defenses during their interaction with live cells, necrotrophs, due to their lifestyle are often confronted with a suite of toxic metabolites. These include an assortment of plant defense compounds (PDCs) which can demonstrate broad antifungal activity. These PDCs can be either constitutively present in plant tissue or induced in response to infection, but are nevertheless an important obstacle which needs to be overcome for successful pathogenesis. Fungal necrotrophs have developed a number of strategies to achieve this goal, from the direct detoxification of these compounds through enzymatic catalysis and modification, to the active transport of various PDCs to achieve toxin sequestration and efflux. Studies have shown across multiple pathogens that the efficient detoxification of host PDCs is both critical for successful infection and often a determinant factor in pathogen host range. Here, we provide a broad and comparative overview of the various mechanisms for PDC detoxification which have been identified in both fungal necrotrophs and fungal pathogens which depend on detoxification during a necrotrophic phase of infection. Furthermore, the effect that these mechanisms have on fungal host range, metabolism, and disease control will be discussed.

scholarly journals The ABC Transporter BcatrB Affects the Sensitivity of Botrytis cinerea to the Phytoalexin Resveratrol and the Fungicide Fenpiclonil

2001 ◽  
Vol 14 (4) ◽  
pp. 562-571 ◽  
Author(s):  
H. Schoonbeek ◽  
G. Del Sorbo ◽  
M. A. De Waard
Keyword(s):  
Amino Acid ◽  
Plant Defense ◽  
Botrytis Cinerea ◽  
Abc Transporter ◽  
Abc Transporters ◽  
Fungal Pathogens ◽  
Broad Host Range ◽  
Defense Compounds ◽  
Acid Protein ◽  
Chemical Groups

During pathogenesis, fungal pathogens are exposed to a variety of fungitoxic compounds. This may be particularly relevant to Botrytis cinerea, a plant pathogen that has a broad host range and, consequently, is subjected to exposure to many plant defense compounds. In practice, the pathogen is controlled with fungicides belonging to different chemical groups. ATP-binding cassette (ABC) transporters might provide protection against plant defense compounds and fungicides by ATP-driven efflux mechanisms. To test this hypothesis, we cloned BcatrB, an ABC transporter-encoding gene from B. cinerea. This gene encodes a 1,439 amino acid protein with nucleotide binding fold (NBF) and transmembrane (TM) domains in a [NBF-TM6]2 topology. The amino acid sequence has 31 to 67% identity with ABC transporters from various fungi. The expression of BcatrB is up regulated by treatment of B. cinerea germlings with the grapevine phytoalexin resveratrol and the fungicide fenpiclonil. BcatrB replacement mutants are not affected in saprophytic growth on different media but are more sensitive to resveratrol and fenpiclonil than the parental isolate. Furthermore, virulence of ΔBcatrB mutants on grapevine leaves was slightly reduced. These results indicate that BcatrB is a determinant in sensitivity of B. cinerea to plant defense compounds and fungicides.

scholarly journals Post-Translational Modifications Drive Success and Failure of Fungal–Host Interactions

2021 ◽  
Vol 7 (2) ◽  
pp. 124
Author(s):  
Charmaine Retanal ◽  
Brianna Ball ◽  
Jennifer Geddes-McAlister
Keyword(s):  
Fungal Pathogens ◽  
Fungal Infections ◽  
Treatment Options ◽  
Global Scale ◽  
Host Cells ◽  
Candida Spp ◽  
Post Translational Modifications ◽  
Fungal Host ◽  
Resistant Species

Post-translational modifications (PTMs) change the structure and function of proteins and regulate a diverse array of biological processes. Fungal pathogens rely on PTMs to modulate protein production and activity during infection, manipulate the host response, and ultimately, promote fungal survival. Given the high mortality rates of fungal infections on a global scale, along with the emergence of antifungal-resistant species, identifying new treatment options is critical. In this review, we focus on the role of PTMs (e.g., phosphorylation, acetylation, ubiquitination, glycosylation, and methylation) among the highly prevalent and medically relevant fungal pathogens, Candida spp., Aspergillus spp., and Cryptococcus spp. We explore the role of PTMs in fungal stress response and host adaptation, the use of PTMs to manipulate host cells and the immune system upon fungal invasion, and the importance of PTMs in conferring antifungal resistance. We also provide a critical view on the current knowledgebase, pose questions key to our understanding of the intricate roles of PTMs within fungal pathogens, and provide research opportunities to uncover new therapeutic strategies.

Plant Resistance Genes for Fungal Pathogens - Physiological Models and Identification in Cereal Crops

1991 ◽  
Vol 46 (11-12) ◽  
pp. 969-981 ◽  
Author(s):  
Wolfgang Knogge
Keyword(s):  
Plant Defense ◽  
Resistance Genes ◽  
Fungal Pathogens ◽  
Plant Protection ◽  
Defense Responses ◽  
Avirulence Gene ◽  
Physiological Models ◽  
Plant Genes ◽  
Plant Pathogen Interaction

The complex biological phenomenon “resistance” can be reduced to single Mendelian traits acting on both the plant and the pathogen side in a number of pathosystems. According to the “gene-for-gene hypothesis”, the outcome of a plant/pathogen interaction in these cases is incompatibility if a plant carrying a particular resistance gene and a pathogen with the complementary avirulence gene meet. This suggests a causal role of resistance genes in a recognition process initiating active plant defense responses. Fundamentally different strategies are followed to identify these genes molecularly depending on the plant and pathogen species involved. Fungal diseases of crop plants, especially those of cereals, cause dramatic yield losses worldwide. It is assumed that a molecular characterization of plant genes conferring resistance to fungal pathogens will lead to a better understanding of the plant defense system in general permitting the development of new methods of crop plant protection.

The Importance of Reporting New Host-Fungus Records for Ornamental and Regional Crops

2009 ◽  
Vol 10 (1) ◽  
pp. 34
Author(s):  
Frank M. Dugan ◽  
Dean A. Glawe ◽  
Renuka N. Attanayake ◽  
Weidong Chen
Keyword(s):  
Host Range ◽  
Health Professionals ◽  
New Record ◽  
Fungal Pathogens ◽  
New Records ◽  
Plant Diseases ◽  
Timely Manner ◽  
New Host ◽  
Host Fungus ◽  
Voucher Specimens

Accurate and timely reports of new host-fungus records are essential for diagnostics and identification, management, and prevention of plant diseases. Important also are venues to publish these reports in a timely manner and the ability to rapidly search for the information contained in these reports. Presented herein are examples of first reports of fungal pathogens on regional crops, including ornamentals and turf grasses, which illustrate how first reports contribute to preparedness, accurate diagnostics, and knowledge of biogeography and host range. We provide a guide to sources of host-fungus records, discuss venues for publishing new records, and review the information important in a new record, including deposition of voucher specimens. We appeal to plant health professionals to increase their efforts of discovering, documenting, and reporting new records. Accepted for publication 13 March 2009. Published 12 May 2009.

scholarly journals Regulation of Plant Defense Responses by Signals from Fungal Pathogens.

1995 ◽  
Vol 69 (2) ◽  
pp. 174-177
Author(s):  
Tomonori Shiraishi ◽  
Tetsuji Yamada ◽  
Yuki Ichinose
Keyword(s):  
Plant Defense ◽  
Fungal Pathogens ◽  
Defense Responses ◽  
Plant Defense Responses

The Genetic Architecture of Plant Defense Trade-offs in a Common Monkeyflower

2020 ◽  
Author(s):  
Nicholas J Kooyers ◽  
Abigail Donofrio ◽  
Benjamin K Blackman ◽  
Liza M Holeski
Keyword(s):  
Growth Rate ◽  
Plant Defense ◽  
Genetic Linkage ◽  
Genetic Architecture ◽  
Life History Traits ◽  
Total Concentration ◽  
Defense Compounds ◽  
Genetic Constraints ◽  
Trade Offs ◽  
Phenylpropanoid Glycosides

Abstract Determining how adaptive combinations of traits arose requires understanding the prevalence and scope of genetic constraints. Frequently observed phenotypic correlations between plant growth, defenses, and/or reproductive timing have led researchers to suggest that pleiotropy or strong genetic linkage between variants affecting independent traits is pervasive. Alternatively, these correlations could arise via independent mutations in different genes for each trait and extensive correlational selection. Here we evaluate these alternatives by conducting a quantitative trait loci (QTL) mapping experiment involving a cross between 2 populations of common monkeyflower (Mimulus guttatus) that differ in growth rate as well as total concentration and arsenal composition of plant defense compounds, phenylpropanoid glycosides (PPGs). We find no evidence that pleiotropy underlies correlations between defense and growth rate. However, there is a strong genetic correlation between levels of total PPGs and flowering time that is largely attributable to a single shared QTL. While this result suggests a role for pleiotropy/close linkage, several other QTLs also contribute to variation in total PPGs. Additionally, divergent PPG arsenals are influenced by a number of smaller-effect QTLs that each underlie variation in 1 or 2 PPGs. This result indicates that chemical defense arsenals can be finely adapted to biotic environments despite sharing a common biochemical precursor. Together, our results show correlations between defense and life-history traits are influenced by pleiotropy or genetic linkage, but genetic constraints may have limited impact on future evolutionary responses, as a substantial proportion of variation in each trait is controlled by independent loci.

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.

Evaluation of Indigenous Fungal Pathogens from Horse Purslane (Trianthema portulacastrum) for Their Relative Virulence and Host Range Assessments to Select a Potential Mycoherbicidal Agent

Weed Science ◽  
2013 ◽  
Vol 61 (4) ◽  
pp. 580-585 ◽  
Author(s):  
Puja Ray ◽  
Lakshmi Sumitra Vijayachandran
Keyword(s):  
Biological Control ◽  
Host Range ◽  
Fungal Pathogens ◽  
Fungal Species ◽  
Agricultural Fields ◽  
Infected Horse ◽  
Trianthema Portulacastrum ◽  
Weed Plants ◽  
Phoma Herbarum ◽  
Biocontrol Potential

Periodic surveys were conducted to seek potential indigenous fungal agents for development as mycoherbicides against horse purslane, a major weed of agricultural fields in India. Pathogenic fungal species were isolated and identified from naturally infected horse purslane. The biocontrol potential of these pathogens for horse purslane was evaluated by studying their host range and virulence under growth chamber and greenhouse conditions. Three candidates,Alternaria alternata, Fusarium oxysporum, andPhoma herbarum, were identified as potential candidates for biological control of horse purslane. Preliminary host-range tests and pathogenicity studies, conducted using 45 crop and weed plants belonging to 18 families, demonstrated thatP. herbarumprovided effective weed control and was safe to most of the plant species tested. Further mycoherbicidal application ofP. herbarumas plant spray under field condition caused mortality of horse purslane 60 d after application of the inoculums.Phoma herbarumis a good mycoherbicide candidate against horse purslane.

scholarly journals Epigenetic Mechanisms: An Emerging Player in Plant-Microbe Interactions

2016 ◽  
Vol 29 (3) ◽  
pp. 187-196 ◽  
Author(s):  
Qian-Hao Zhu ◽  
Wei-Xing Shan ◽  
Michael A. Ayliffe ◽  
Ming-Bo Wang
Keyword(s):  
Plant Defense ◽  
Defense Mechanisms ◽  
Fungal Pathogens ◽  
Epigenetic Mechanisms ◽  
Cellular Mechanisms ◽  
Plant Host ◽  
Positive Role ◽  
Transcriptional Reprogramming ◽  
Pathogen Challenge ◽  
Microbe Interactions

Plants have developed diverse molecular and cellular mechanisms to cope with a lifetime of exposure to a variety of pathogens. Host transcriptional reprogramming is a central part of plant defense upon pathogen recognition. Recent studies link DNA methylation and demethylation as well as chromatin remodeling by posttranslational histone modifications, including acetylation, methylation, and ubiquitination, to changes in the expression levels of defense genes upon pathogen challenge. Remarkably these inducible defense mechanisms can be primed prior to pathogen attack by epigenetic modifications and this heightened resistance state can be transmitted to subsequent generations by inheritance of these modification patterns. Beside the plant host, epigenetic mechanisms have also been implicated in virulence development of pathogens. This review highlights recent findings and insights into epigenetic mechanisms associated with interactions between plants and pathogens, in particular bacterial and fungal pathogens, and demonstrates the positive role they can have in promoting plant defense.

scholarly journals StuA-Regulated Processes in the Dermatophyte Trichophyton rubrum: Transcription Profile, Cell-Cell Adhesion, and Immunomodulation

2021 ◽  
Vol 11 ◽  
Author(s):  
Tamires A. Bitencourt ◽  
João Neves-da-Rocha ◽  
Maira P. Martins ◽  
Pablo R. Sanches ◽  
Elza A. S. Lang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcription Factors ◽  
Fungal Pathogens ◽  
Trichophyton Rubrum ◽  
Fungal Infections ◽  
Critical Role ◽  
Cell Interaction ◽  
Substantial Impact ◽  
Fungal Host ◽  
Cell Cell

Fungal infections represent a significant concern worldwide, contributing to human morbidity and mortality. Dermatophyte infections are among the most significant mycoses, and Trichophyton rubrum appears to be the principal causative agent. Thus, an understanding of its pathophysiology is urgently required. Several lines of evidence have demonstrated that the APSES family of transcription factors (Asm1p, Phd1p, Sok2p, Efg1p, and StuA) is an important point of vulnerability in fungal pathogens and a potential therapeutic target. These transcription factors are unique to fungi, contributing to cell differentiation and adaptation to environmental cues and virulence. It has recently been demonstrated that StuA plays a pleiotropic role in dermatophyte pathophysiology. It was suggested that it functions as a mediator of crosstalk between different pathways that ultimately contribute to adaptive responses and fungal-host interactions. The complex regulation of StuA and its interaction pathways are yet to be unveiled. Thus, this study aimed to gain a deeper understanding of StuA-regulated processes in T. rubrum by assessing global gene expression following growth on keratin or glucose sources. The data showed the involvement of StuA in biological processes related to central carbon metabolism and glycerol catabolism, reactive oxygen species metabolism, and cell wall construction. Changes in carbohydrate metabolism may be responsible for the significant alteration in cell wall pattern and consequently in cell-cell interaction and adhesion. Loss of StuA led to impaired biofilm production and promoted proinflammatory cytokine secretion in a human keratinocyte cell line. We also observed the StuA-dependent regulation of catalase genes. Altogether, these data demonstrate the multitude of regulatory targets of StuA with a critical role in central metabolism that may ultimately trigger a cascade of secondary effects with substantial impact on fungal physiology and virulence traits.

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