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.

scholarly journals Effector Biology in Focus: A Primer for Computational Prediction and Functional Characterization

2018 ◽  
Vol 31 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Ronaldo J. D. Dalio ◽  
John Herlihy ◽  
Tiago S. Oliveira ◽  
John M. McDowell ◽  
Marcos Machado
Keyword(s):  
Disease Control ◽  
Plant Pathogen ◽  
Biological Diversity ◽  
Cell Structure ◽  
Functional Characterization ◽  
Computational Prediction ◽  
Effector Proteins ◽  
Immune Recognition ◽  
Plant Pathogen Interactions ◽  
The Impact

Plant–pathogen interactions are controlled by a multilayered immune system, which is activated by pathogen recognition in the host. Pathogens secrete effector molecules to interfere with the immune recognition or signaling network and reprogram cell structure or metabolism. Understanding the effector repertoires of diverse pathogens will contribute to unraveling the molecular mechanism of virulence and developing sustainable disease-control strategies for crops and natural ecosystems. Effector functionality has been investigated extensively in only a small number of pathogen species. However, many more pathogen genomes are becoming available, and much can be learned from a broader view of effector biology in diverse pathosystems. The purpose of this review is to summarize methodology for computational prediction of protein effectors, functional characterization of effector proteins and their targets, and the use of effectors as probes to screen for new sources of host resistance. Although these techniques were generally developed in model pathosystems, many of the approaches are directly applicable for exploration and exploitation of effector biology in pathosystems that are less well studied. We hope to facilitate such exploration, which will broaden understanding of the mechanisms that underpin the biological diversity of plant–pathogen interactions, and maximize the impact of new approaches that leverage effector biology for disease control.

Extracellular hydrolytic enzymes in the fungal genus Verticillium: adaptations for pathogenesis

1999 ◽  
Vol 45 (10) ◽  
pp. 856-864 ◽  
Author(s):  
Michael J Bidochka ◽  
Susan Burke ◽  
Luna Ng
Keyword(s):  
Plant Pathogen ◽  
Plant Pathogens ◽  
Plant Cell Wall ◽  
Extracellular Enzymes ◽  
Hydrolytic Enzymes ◽  
Pathogenic Fungi ◽  
Verticillium Lecanii ◽  
Opportunistic Pathogens ◽  
Broad Array ◽  
Fungal Genus

The insect and plant pathogens within the fungal genus Verticillium showed enzymatic adaptation (production and regulation) directed to the degradation of some of the polymers found in the integument of their respective hosts. For example, the facultative plant pathogens (V. albo-atrum and V. dahliae) produced greater levels of cellulase and xylanase than the facultative insect pathogen (V. lecanii). Verticillium lecanii produced extracellular subtilisin-like protease when grown in insect cuticle medium but not in plant cell wall medium, while the plant pathogen V. albo-atrum showed a diminished regulatory component in the production of this enzyme. The opportunistic pathogens (V. fungicola and V. coccosporum) and the saprobic species (V. rexianum) were less specific in the production and regulation of several proteases as well as cellulases and xylanases. A dendrogram based on cluster analysis compiled from fungal API-ZYM profiles showed commonalties in a broad array of extracellular enzymes within a host-pathogen group (i.e. insect or plant pathogen). The opportunistic pathogens were dispersed throughout the dendrogram, suggestive of the diversity in type and expression of extracellular enzymes.Key words: extracellular enzymes, pathogenic fungi.

scholarly journals Co-Occurrence of Viruses, Plant Pathogens, and Symbionts in an Underexplored Hemipteran Clade

2021 ◽  
Vol 11 ◽  
Author(s):  
McKinlee M. Salazar ◽  
Mônica T. Pupo ◽  
Amanda M. V. Brown
Keyword(s):  
Plant Pathogen ◽  
Plant Pathogens ◽  
Plant Viruses ◽  
Metagenomic Sequencing ◽  
Base Pairs ◽  
Shotgun Metagenomic Sequencing ◽  
Data Clusters ◽  
Blast Database ◽  
Insect Symbionts ◽  
Plant Pathogen Interactions

Interactions between insect symbionts and plant pathogens are dynamic and complex, sometimes involving direct antagonism or synergy and sometimes involving ecological and evolutionary leaps, as insect symbionts transmit through plant tissues or plant pathogens transition to become insect symbionts. Hemipterans such as aphids, whiteflies, psyllids, leafhoppers, and planthoppers are well-studied plant pests that host diverse symbionts and vector plant pathogens. The related hemipteran treehoppers (family Membracidae) are less well-studied but offer a potentially new and diverse array of symbionts and plant pathogenic interactions through their distinct woody plant hosts and ecological interactions with diverse tending hymenopteran taxa. To explore membracid symbiont–pathogen diversity and co-occurrence, this study performed shotgun metagenomic sequencing on 20 samples (16 species) of treehopper, and characterized putative symbionts and pathogens using a combination of rapid blast database searches and phylogenetic analysis of assembled scaffolds and correlation analysis. Among the 8.7 billion base pairs of scaffolds assembled were matches to 9 potential plant pathogens, 12 potential primary and secondary insect endosymbionts, numerous bacteriophages, and other viruses, entomopathogens, and fungi. Notable discoveries include a divergent Brenneria plant pathogen-like organism, several bee-like Bombella and Asaia strains, novel strains of Arsenophonus-like and Sodalis-like symbionts, Ralstonia sp. and Ralstonia-type phages, Serratia sp., and APSE-type phages and bracoviruses. There were several short Phytoplasma and Spiroplasma matches, but there was no indication of plant viruses in these data. Clusters of positively correlated microbes such as yeast-like symbionts and Ralstonia, viruses and Serratia, and APSE phage with parasitoid-type bracoviruses suggest directions for future analyses. Together, results indicate membracids offer a rich palette for future study of symbiont–plant pathogen interactions.

scholarly journals Apoplastic Cell Death-Inducing Proteins of Filamentous Plant Pathogens: Roles in Plant-Pathogen Interactions

2020 ◽  
Vol 11 ◽  
Author(s):  
Ya Li ◽  
Yijuan Han ◽  
Mengyu Qu ◽  
Jia Chen ◽  
Xiaofeng Chen ◽  
...  
Keyword(s):  
Cell Death ◽  
Plant Pathogen ◽  
Plant Pathogens ◽  
Plant Pathogen Interactions

scholarly journals CRISPR-Cas systems in the plant pathogen Xanthomonas spp. and their impact on genome plasticity

2019 ◽  
Author(s):  
Paula Maria Moreira Martins ◽  
Andre da Silva Xavier ◽  
Marco Aurelio Takita ◽  
Poliane Alfemas-Zerbini ◽  
Alessandra Alves de Souza
Keyword(s):  
Phylogenetic Analysis ◽  
Plant Pathogen ◽  
Significant Variation ◽  
Crop Production ◽  
Plant Pathogens ◽  
Economic Losses ◽  
Genome Plasticity ◽  
Plant Pathogen Interactions ◽  
Cas Proteins

AbstractXanthomonas is one of the most important bacterial genera of plant pathogens causing economic losses in crop production worldwide. Despite its importance, many aspects of basic Xanthomonas biology remain unknown or understudied. Here, we present the first genus-wide analysis of CRISPR-Cas in Xanthomonas and describe specific aspects of its occurrence. Our results show that Xanthomonas genomes harbour subtype I-C and I-F CRISPR-Cas systems and that species belonging to distantly Xanthomonas-related genera in Xanthomonadaceae exhibit the same configuration of coexistence of the I-C and I-F CRISPR subtypes. Additionally, phylogenetic analysis using Cas proteins indicated that the CRISPR systems present in Xanthomonas spp. are the result of an ancient acquisition. Despite the close phylogeny of these systems, they present significant variation in both the number and targets of spacers. An interesting characteristic observed in this study was that the identified plasmid-targeting spacers were always driven toward plasmids found in other Xanthomonas strains, indicating that CRISPR-Cas systems could be very effective in coping with plasmidial infections. Since many effectors are plasmid encoded, CRISPR-Cas might be driving specific characteristics of plant-pathogen interactions.

scholarly journals The dual function receptor kinase, OsWAKL21.2, is involved in elaboration of lipaseA/esterase induced immune responses in rice

2019 ◽  
Author(s):  
Kamal Kumar Malukani ◽  
Ashish Ranjan ◽  
Hota Shiva Jyothi ◽  
Hitendra Kumar Patel ◽  
Ramesh V. Sonti
Keyword(s):  
Cell Wall ◽  
Immune Responses ◽  
Plant Pathogens ◽  
Plant Cell Wall ◽  
Ectopic Expression ◽  
Dual Function ◽  
Receptor Kinase ◽  
Cell Wall Degrading Enzymes ◽  
Cell Wall Damage

AbstractPlant pathogens secrete cell wall degrading enzymes (CWDEs) to degrade various components of the plant cell wall. Plants sense this cell wall damage as a mark of infection and induce immune responses. Little is known about the plant functions that are involved in the elaboration of cell wall damage-induced immune responses. Transcriptome analysis revealed that a rice receptor kinase, WALL-ASSOCIATED KINASE-LIKE 21 (OsWAKL21.2), is upregulated following treatment with either Xanthomonas oryzae pv. oryzae (Xoo, a bacterial pathogen) or lipaseA/esterase (LipA: a CWDE of Xoo). Downregulation of OsWAKL21.2 attenuates LipA mediated immune responses. Overexpression of OsWAKL21.2 in rice mimics LipA treatment mediated induction of immune responses and enhanced expression of defence related genes, indicating it could be involved in the perception of LipA induced cell wall damage in rice. OsWAKL21.2 is a dual function kinase having in-vitro kinase and guanylate cyclase (GC) activities. Ectopic expression of OsWAKL21.2 in Arabidopsis also activates plant immune responses. Interestingly, OsWAKL21.2 needs kinase activity to activate rice immune responses while in Arabidopsis it needs GC activity. Our study reveals a novel receptor kinase involved in elaboration of cell wall damage induced rice immune responses that can activate similar immune responses in two different species via two different mechanisms.One sentence SummaryA novel rice receptor WAKL21 that sense cell wall damage caused by Xanthomonas secreted cell wall degrading enzyme to induce immune responses.

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 Functional Variation of Plant–Pathogen Interactions: New Concept and Methods for Virulence Data Analyses

2019 ◽  
Vol 109 (8) ◽  
pp. 1324-1330 ◽  
Author(s):  
E. Kosman ◽  
X. Chen ◽  
A. Dreiseitl ◽  
B. McCallum ◽  
A. Lebeda ◽  
...  
Keyword(s):  
Plant Pathogen ◽  
Plant Pathogens ◽  
Infection Type ◽  
Lesion Size ◽  
Data Sets ◽  
Functional Variation ◽  
Multiple Loci ◽  
Plant Pathogen Interaction ◽  
Few Data ◽  
Plant Pathogen Interactions

Classical virulence analysis is based on discovering virulence phenotypes of isolates with regard to a composition of resistance genes in a differential set of host genotypes. With such a vision, virulence phenotypes are usually treated in a genetic manner as one of two possible alleles, either virulence or avirulence in a binary locus. Therefore, population genetics metrics and methods have become prevailing tools for analyzing virulence data at multiple loci. However, a basis for resolving binary virulence phenotypes is infection type (IT) data of host–pathogen interaction that express functional traits of each specific isolate in a given situation (particular host, environmental conditions, cultivation practice, and so on). IT is determined by symptoms and signs observed (e.g., lesion type, lesion size, coverage of leaf or leaf segments by mycelium, spore production and so on), and assessed by IT scores at a generally accepted scale for each plant–pathogen system. Thus, multiple IT profiles of isolates are obtained and can be subjected to analysis of functional variation within and among operational units of a pathogen. Such an approach may allow better utilization of the information available in the raw data, and reveal a functional (e.g., environmental) component of pathogen variation in addition to the genetic one. New methods for measuring functional variation of plant–pathogen interaction with IT data were developed. The methods need an appropriate assessment scale and expert estimations of dissimilarity between IT scores for each plant–pathogen system (an example is presented). Analyses of a few data sets at different hierarchical levels demonstrated discrepancies in results obtained with IT phenotypes versus binary virulence phenotypes. The ability to measure functional IT-based variation offers promise as an effective tool in the study of epidemics caused by plant pathogens.

scholarly journals Plant-mediated interactions between a vector and a non-vector herbivore promote the spread of a plant virus

2019 ◽  
Vol 286 (1911) ◽  
pp. 20191383 ◽  
Author(s):  
Paul J. Chisholm ◽  
Sanford D. Eigenbrode ◽  
Robert E. Clark ◽  
Saumik Basu ◽  
David W. Crowder
Keyword(s):  
Plant Pathogen ◽  
Disease Ecology ◽  
Structural Equation ◽  
Plant Pathogens ◽  
Structural Equation Models ◽  
Plant Defence ◽  
Defence Genes ◽  
Managed Ecosystems ◽  
Plant Defence Genes ◽  
Plant Susceptibility

Herbivores that transmit plant pathogens often share hosts with non-vector herbivores. These co-occurring herbivores can affect vector fitness and behaviour through competition and by altering host plant quality. However, few studies have examined how such interactions may both directly and indirectly influence the spread of a plant pathogen. Here, we conducted field and greenhouse trials to assess whether a defoliating herbivore ( Sitona lineatus ) mediated the spread of a plant pathogen, Pea enation mosaic virus (PEMV), by affecting the fitness and behaviour of Acrythosiphon pisum , the PEMV vector. We observed higher rates of PEMV spread when infectious A. pisum individuals shared hosts with S. lineatus individuals. Using structural equation models, we showed that herbivory from S. lineatus increased A. pisum fitness, which stimulated vector movement and PEMV spread. Moreover, plant susceptibility to PEMV was indirectly enhanced by S. lineatus , which displaced A. pisum individuals to the most susceptible parts of the plant. Subsequent analyses of plant defence genes revealed considerable differences in plant phytohormones associated with anti-herbivore and anti-pathogen defence when S. lineatus was present. Given that vectors interact with non-vector herbivores in natural and managed ecosystems, characterizing how such interactions affect pathogens would greatly enhance our understanding of disease ecology.

scholarly journals The Age of Effectors: Genome-Based Discovery and Applications

2016 ◽  
Vol 106 (10) ◽  
pp. 1206-1212 ◽  
Author(s):  
Hesham A. Y. Gibriel ◽  
Bart P. H. J. Thomma ◽  
Michael F. Seidl
Keyword(s):  
Plant Pathogen ◽  
Plant Pathogens ◽  
Gene Annotation ◽  
Functional Characterization ◽  
Resistance Breeding ◽  
Infection Process ◽  
Microbial Pathogens ◽  
Global Food Security ◽  
Pathogen Effector ◽  
Pathogen Populations

Microbial pathogens cause devastating diseases on economically and ecologically important plant species, threatening global food security, and causing billions of dollars of losses annually. During the infection process, pathogens secrete so-called effectors that support host colonization, often by deregulating host immune responses. Over the last decades, much of the research on molecular plant-microbe interactions has focused on the identification and functional characterization of such effectors. The increasing availability of sequenced plant pathogen genomes has enabled genomics-based discovery of effector candidates. Nevertheless, identification of full plant pathogen effector repertoires is often hampered by erroneous gene annotation and the localization effector genes in genomic regions that are notoriously difficult to assemble. Here, we argue that recent advances in genome sequencing technologies, genome assembly, gene annotation, as well as effector identification methods hold promise to disclose complete and correct effector repertoires. This allows to exploit complete effector repertoires, and knowledge of their diversity within pathogen populations, to develop durable and sustainable resistance breeding strategies, disease control, and management of plant pathogens.

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