Effectors of biotrophic fungal plant pathogens

2010 ◽  
Vol 37 (10) ◽  
pp. 913 ◽  
Author(s):  
Pamela H. P. Gan ◽  
Maryam Rafiqi ◽  
Adrienne R. Hardham ◽  
Peter N. Dodds
Keyword(s):  
Plant Tissue ◽  
Fungal Pathogen ◽  
Plant Pathogens ◽  
Plant Cells ◽  
Host Cells ◽  
Plant Proteins ◽  
Living Plant ◽  
Host Cytoplasm ◽  
Fungal Plant Pathogens ◽  
Biotrophic Fungi

Plant pathogenic biotrophic fungi are able to grow within living plant tissue due to the action of secreted pathogen proteins known as effectors that alter the response of plant cells to pathogens. The discovery and identification of these proteins has greatly expanded with the sequencing and annotation of fungal pathogen genomes. Studies to characterise effector function have revealed that a subset of these secreted pathogen proteins interact with plant proteins within the host cytoplasm. This review focuses on the effectors of intracellular biotrophic and hemibiotrophic fungal plant pathogens and summarises advances in understanding the roles of these proteins in disease and in elucidating the mechanism of fungal effector uptake into host cells.

scholarly journals Identification of a Protein from Rust Fungi Transferred from Haustoria into Infected Plant Cells

2005 ◽  
Vol 18 (11) ◽  
pp. 1130-1139 ◽  
Author(s):  
Eric Kemen ◽  
Ariane C. Kemen ◽  
Maryam Rafiqi ◽  
Uta Hempel ◽  
Kurt Mendgen ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Polyclonal Antibodies ◽  
Rust Fungus ◽  
Infected Plant ◽  
Plant Cells ◽  
Host Cells ◽  
Nuclear Localization Signals ◽  
Uromyces Fabae ◽  
Host Cytoplasm ◽  
Functional Efficiency

The formation of haustoria is one of the hallmarks of the interaction of obligate biotrophic fungi with their host plants. In addition to their role in nutrient uptake, it is hypothesized that haustoria are actively involved in establishing and maintaining the biotrophic relationship. We have identified a 24.3-kDa protein that exhibited a very unusual allocation. Rust transferred protein 1 from Uromyces fabae (Uf-RTP1p) was not only detected in the host parasite interface, the extrahaustorial matrix, but also inside infected plant cells by immunofluorescence and electron microscopy. Uf-RTP1p does not exhibit any similarity to sequences currently listed in the public databases. However, we identified a homolog of Uf-RTP1p in the related rust fungus Uromyces striatus (Us-RTP1p). The localization of Uf-RTP1p and Us-RTP1p inside infected plant cells was confirmed, using four independently raised polyclonal antibodies. Depending on the developmental stage of haustoria, Uf-RTP1p was found in increasing amounts in host cells, including the host nucleus. Putative nuclear localization signals (NLS) were found in the predicted RTP1p sequences. However, functional efficiency could only be verified for the Uf-RTP1p NLS by means of green fluorescent protein fusions in transformed tobacco protoplasts. Western blot analysis indicated that Uf-RTP1p and Us-RTP1p most likely enter the host cell as N-glycosylated proteins. However, the mechanism by which they cross the extrahaustorial membrane and accumulate in the host cytoplasm is unknown. The localization of RTP1p suggests that it might play an important role in the maintenance of the biotrophic interaction.

scholarly journals Signatures of Adaptation to Obligate Biotrophy in the Hyaloperonospora arabidopsidis Genome

Science ◽  
2010 ◽  
Vol 330 (6010) ◽  
pp. 1549-1551 ◽  
Author(s):  
Laura Baxter ◽  
Sucheta Tripathy ◽  
Naveed Ishaque ◽  
Nico Boot ◽  
Adriana Cabral ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Inorganic Nitrogen ◽  
Living Plant ◽  
Rxlr Effectors ◽  
Fungal Plant Pathogens ◽  
Genes Encoding ◽  
Zoospore Formation ◽  
Hyaloperonospora Arabidopsidis ◽  
Obligate Biotrophs ◽  
Obligate Biotroph

Many oomycete and fungal plant pathogens are obligate biotrophs, which extract nutrients only from living plant tissue and cannot grow apart from their hosts. Although these pathogens cause substantial crop losses, little is known about the molecular basis or evolution of obligate biotrophy. Here, we report the genome sequence of the oomycete Hyaloperonospora arabidopsidis (Hpa), an obligate biotroph and natural pathogen of Arabidopsis thaliana. In comparison with genomes of related, hemibiotrophic Phytophthora species, the Hpa genome exhibits dramatic reductions in genes encoding (i) RXLR effectors and other secreted pathogenicity proteins, (ii) enzymes for assimilation of inorganic nitrogen and sulfur, and (iii) proteins associated with zoospore formation and motility. These attributes comprise a genomic signature of evolution toward obligate biotrophy.

scholarly journals Population genomics reveals molecular determinants of specialization to tomato in the polyphagous fungal pathogen Botrytis cinerea in France

2021 ◽  
Author(s):  
Alex Mercier ◽  
Adeline Simon ◽  
Nicolas Lapalu ◽  
Tatiana Giraud ◽  
Marc Bardin ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Fungal Pathogen ◽  
Plant Pathogens ◽  
Population Genomics ◽  
Grey Mould ◽  
Host Specialization ◽  
Genomic Changes ◽  
Fungal Plant Pathogens ◽  
Synonymous Sites ◽  
Pathogen Populations

Many fungal plant pathogens encompass multiple populations specialized on different plant species. Understanding the factors underlying pathogen adaptation to their hosts is a major challenge of evolutionary microbiology, and it should help preventing the emergence of new specialized pathogens on novel hosts. Previous studies have shown that French populations of the grey mould pathogen Botrytis cinerea parasitizing tomato and grapevine are differentiated from each other, and have higher aggressiveness on their host-of-origin than on other hosts, indicating some degree of host specialization in this polyphagous pathogen. Here, we aimed at identifying the genomic features underlying the specialization of B. cinerea populations to tomato and grapevine. Based on whole genome sequences of 32 isolates, we confirmed the subdivision of B. cinerea pathogens into two genetic clusters on grapevine and another, single cluster on tomato. Levels of genetic variation in the different clusters were similar, suggesting that the tomato-specific cluster has not recently emerged following a bottleneck. Using genome scans for selective sweeps and divergent selection, tests of positive selection based on polymorphism and divergence at synonymous and non-synonymous sites and analyses of presence/absence variation, we identified several candidate genes that represent possible determinants of host specialization in the tomato-associated population. This work deepens our understanding of the genomic changes underlying the specialization of fungal pathogen populations.

Topographical signaling for cell differentiation in the plant pathogenic fungus, Uromyces

1989 ◽  
Vol 47 ◽  
pp. 784-785
Author(s):  
H.C. Hoch
Keyword(s):  
Plant Pathogens ◽  
Developmental Process ◽  
Pathogenic Fungus ◽  
Host Cells ◽  
Subsequent Infection ◽  
Infection Structures ◽  
Rust Diseases ◽  
Fungal Plant Pathogens ◽  
Plant Signals ◽  
Important Structure

Fungal plant pathogens invade host cells with a variety of specialized infection structures, however, for most fungi the appressorium is developmentally the first and most important structure to be formed in preparation for host colonization. It must be positioned at an appropriate site on the host in a timely way so that subsequent infection can be assured. For fungi which cause rust diseases of plants, positioning the appressorium is the most critical stage because invasion of the host can occur only via the stomata. Uredospores of these fungi (e.g.,Uromyces appendiculatus) germinate and grow, directed by the leaf (bean) surface topography toward stomata where they cease growth and develop appressoria directly over the stomatal openings. Development of the appressorium is accompanied by ameboid-like migration of the cytoplasm into the ballooning hyphal tip, DNA synthesis and nuclear division, synthesis of several “differentiation” proteins, and a rearrangement of the cytoskeleton. An orderly succession of subsequent infection structures (e.g., infection pegs, vesicles) follow in a preprogrammed sequence once the initial developmental process has been started.My research goals have been to determine what feature(s) of the host plant signals infection structure formation and how the fungus perceives these signals.

scholarly journals MoCpa1-mediated arginine biosynthesis is crucial for fungal growth, conidiation, and plant infection of Magnaporthe oryzae

2020 ◽  
Author(s):  
Osakina Aron ◽  
Min Wang ◽  
Anjago Wilfred Mabeche ◽  
Batool Wajjiha ◽  
Shuai Yang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Magnaporthe Oryzae ◽  
Plant Pathogens ◽  
De Novo ◽  
Pathogenic Fungi ◽  
Host Cells ◽  
Arginine Biosynthesis ◽  
Carbamoyl Phosphate ◽  
Genome Database ◽  
Fungal Plant Pathogens

AbstractArginine is an important amino acid involved in processes such as cell signal transduction, protein synthesis, and sexual reproduction. To understand the biological roles of arginine biosynthesis in pathogenic fungi, we used Cpa1, the carbamoyl phosphate synthase arginine-specific small chain subunit in Saccharomyces cerevisiae as a query to identify its ortholog in Magnaporthe oryzae genome database and named it MoCpa1. MoCpa1 is a 471-amino acid protein containing the CPSase_sm_chain domain and the GATase domain. MoCpa1 transcripts were highly expressed at the conidiation, early-infection, and late-infection stages of the fungus. Targeted deletion of MoCPA1 gene resulted in the ΔMocpa1 mutant exhibiting arginine auxotrophy on MM, confirming its role in de novo arginine biosynthesis. The ΔMocpa1 mutant presented significantly decreased sporulation with some of its conidia being defective in morphology. Furthermore, the ΔMocpa1 mutant was nonpathogenic on rice and barley leaves, which was a result of defects in appressorium-mediated penetration and restricted invasive hyphal growth within host cells. Addition of exogenous arginine partially rescued conidiation and pathogenicity defects on the barley and rice leaves, while introduction of MoCPA1 gene in ΔMocpa1 mutant fully complemented the lost phenotype. Further confocal microscopy examination revealed that MoCpa1 is localized in the mitochondria. In summary, our results demonstrate that MoCpa1-mediated arginine biosynthesis is crucial for fungal development, conidiation, appressorium formation and infection-related morphogenesis in M. oryzae, thus serving as an attractive target for mitigating obstinate fungal plant pathogens.

scholarly journals Geography, Plants, and Growing Systems Shape the Genetic Structure of Tunisian Botrytis cinerea Populations

2008 ◽  
Vol 98 (12) ◽  
pp. 1271-1279 ◽  
Author(s):  
S. Karchani-Balma ◽  
A. Gautier ◽  
A. Raies ◽  
E. Fournier
Keyword(s):  
Botrytis Cinerea ◽  
Fungal Pathogen ◽  
Plant Pathogens ◽  
Geographic Origin ◽  
Genotypic Diversity ◽  
Fungal Plant Pathogens ◽  
Long Time ◽  
Faba Beans ◽  
New Hosts ◽  
Open Fields

Botrytis cinerea, considered for a long time as a generalist fungal pathogen of a multitude of plants, was recently shown to exhibit significant population structure in France according to the host, suggesting sympatric specialization. Recent models also showed that adaptation to new hosts may facilitate the process of sympatric speciation in fungal plant pathogens. The present work aimed at investigating if host plants, combined with geographic origin and growing systems, shape the diversity and structure of Tunisian populations of B. cinerea. We genotyped 153 isolates with 9 microsatellites. In all the investigated populations, the fungus reproduced mainly sexually. Gene flow was significantly reduced between greenhouses and open fields from strawberry but not from grapevine. Populations from tomatoes, sampled under greenhouses only, exhibited a low genotypic diversity. The effects of plant and geography from open fields were investigated on a sample of 74 isolates. Six populations were inferred, mainly structured according to a geographic barrier corresponding to the Grande Dorsale Mountain. However, this effect could not be separated from the host plant origin of isolates. The analysis of 63 isolates recovered from strawberries and faba beans in the Cap Bon and Centre regions did not reveal any significant effect of plant on pathogen population differentiation.

scholarly journals Potential of Mycovirus in the Biological Control of Fungal Plant Pathogens: A Review

2020 ◽  
Vol 41 (03) ◽  
Author(s):  
I. Yimjenjang Longkumer ◽  
Md. Abbas Ahmad
Keyword(s):  
Biological Control ◽  
Fungal Pathogen ◽  
Plant Pathogens ◽  
Molecular Level ◽  
Control Strategies ◽  
Severe Infection ◽  
Vital Role ◽  
Yield Losses ◽  
Formidable Challenge ◽  
Fungal Plant Pathogens

Fungal pathogenic populations such as Sclerotinia, Rhizoctonia and Fusarium are ubiquitous and have broad range of host enabling them to cause a severe infection resulting in huge yield losses. Albeit the various tactics such as cultural, mechanical implemented to counteract the havoc, it still creates a formidable challenge to the researchers to keep the pathogenic population below threshold. From Eco-friendly sustenance perspective, Biological control can play a vital role in combination along with the other efficient tactics. In field condition various strains are available having two characters namely virulent and hypovirulent, the latter may exhibit hypovirulent nature genetically or due to the invasion of mycoviruses becomes hypovirulent. In both the cases are of interest to the researchers in studying the biological control exhibited by the mycoviruses. The biocontrol agents include Mycoviruses, which plays a significant role in infecting the virulent fungal pathogen by reducing their virulence giving to a phenomenon known as Hypovirulence. Their genome consist of mostly dsRNA and others include +ssRNA, -ssRNA and dsDNA. These studies in fungal and viral interaction can lead to the development of novel biological control strategies and help us to explore upto the molecular level.

scholarly journals ApoplastP: prediction of effectors and plant proteins in the apoplast using machine learning

2017 ◽  
Author(s):  
Jana Sperschneider ◽  
Peter N. Dodds ◽  
Karam B. Singh ◽  
Jennifer M. Taylor
Keyword(s):  
Machine Learning ◽  
Plant Pathogens ◽  
False Positive Rate ◽  
Effector Proteins ◽  
Computational Method ◽  
Host Cells ◽  
Plant Proteins ◽  
Functional Studies ◽  
Positive Rate ◽  
Improving Accuracy

AbstractThe plant apoplast is integral to intercellular signalling, transport and plant-pathogen interactions. Plant pathogens deliver effectors both into the apoplast and inside host cells, but no computational method currently exists to discriminate between these localizations. We present ApoplastP, the first method for predicting if an effector or plant protein localizes to the apoplast. ApoplastP uncovers features for apoplastic localization common to both effectors and plant proteins, namely an enrichment in small amino acids and cysteines as well as depletion in glutamic acid. ApoplastP predicts apoplastic localization in effectors with sensitivity of 75% and false positive rate of 5%, improving accuracy of cysteine-rich classifiers by over 13%. ApoplastP does not depend on the presence of a signal peptide and correctly predicts the localization of unconventionally secreted plant and effector proteins. The secretomes of fungal saprophytes, necrotrophic pathogens and extracellular pathogens are enriched for predicted apoplastic proteins. Rust pathogen secretomes have the lowest percentage of apoplastic proteins, but these are highly enriched for predicted effectors. ApoplastP pioneers apoplastic localization prediction using machine learning. It will facilitate functional studies and will be valuable for predicting if an effector localizes to the apoplast or if it enters plant cells. ApoplastP is available at http://apoplastp.csiro.au.

scholarly journals PacC-dependent adaptation and modulation of host cellular pH controls hemibiotrophic invasive growth and disease development by the rice blast fungus

2020 ◽  
Author(s):  
Xiao-Lin Chen ◽  
Dan He ◽  
Changfa Yin ◽  
Jun Yang ◽  
Jing Sun ◽  
...  
Keyword(s):  
Plant Cells ◽  
Signal Transduction Pathway ◽  
Rice Blast Fungus ◽  
Host Cells ◽  
Blast Disease ◽  
Invasive Growth ◽  
Transduction Pathway ◽  
Alkaline Ph ◽  
Living Plant ◽  
Blast Fungus

AbstractMany of the world’s most serious crop diseases are caused by hemibiotrophic fungi. These pathogens have evolved the ability to colonize living plant cells, suppressing plant immunity responses, before switching to necrotrophic growth, in which host cells die, providing the energy to fuel sporulation and spread of the fungus. How hemibiotrophic pathogens switch between these two lifestyles remains poorly understood. Here, we report that the devastating rice blast fungus, Magnaporthe oryzae, manipulates host cellular pH to regulate hemibiotrophy. During infection by M. oryzae, host plant cells are alkalinized to pH 7.8 during biotrophic growth, but later acidified to pH 6.5 during necrotrophy. Using a forward genetic screen, we identified alkaline-sensitive mutants of M. oryzae that were blocked in biotrophic proliferation and impaired in induction of host cell acidification and necrotrophy. These mutants defined components of the PacC-dependent ambient pH signal transduction pathway in M. oryzae. We report that PacC exists as a full-length repressor, PacC559, and a truncated transcriptional activator, PacC222, which localize to the fungal nucleus during biotrophic growth and to the cytoplasm during necrotrophy. During biotrophy, PacC222 directly activates genes associated with nutrient acquisition and fungal virulence, while PacC559 represses genes associated with saprophytic mycelial growth and sporulation, which are subsequently de-repressed during necrotrophy. When considered together, our results indicate that temporal regulation of hemibiotrophy by M. oryzae requires PacC-dependent sensing and manipulation of host cellular pH.Author SummaryCrop diseases caused by fungi represent some of the most serious threats to global food security. Many fungal pathogens have evolved the ability to invade living plant tissue and suppress host immunity, before switching to a completely different mode of growth, in which they are able to kill host plant cells. This lifestyle– called hemibiotrophy –is exemplified by the blast fungus, Magnaporthe oryzae, which causes devastating diseases of rice, wheat and many other grasses. We found that during infection by M. oryzae, host cells initially have an alkaline pH, when the fungus is growing in living tissue, but pH rapidly becomes acidic, as host tissue is killed. We identified mutants of the blast fungus that were sensitive to alkaline pH and this enabled us to identify the signal transduction pathway by which the fungus responds to changes in ambient pH. We found that mutants in the pH response pathway were blocked in invasive fungal growth and could not cause acidification of host tissue. Consequently, they are unable to cause blast disease. We characterized the central regulator of this pathway, the PacC transcription factor, which unusually can act as both a repressor and an activator of fungal gene expression. During biotrophic invasive growth, PacC activates many genes previously reported to be required for virulence, including several associated with nutrient acquisition, and at the same time represses genes associated with vegetative growth and sporulation. The PacC signaling pathway is therefore necessary for regulating the switch in fungal lifestyle associated with causing blast disease.

scholarly journals Molecular dynamics investigation of the interaction between Colletotrichum capsici cutinase and berberine suggested a mechanism for reduced enzyme activity

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247236
Author(s):  
Ying Li ◽  
Jinqing Wei ◽  
Huizhen Yang ◽  
Jing Dai ◽  
Xizhen Ge
Keyword(s):  
Molecular Dynamics ◽  
Fungal Pathogen ◽  
Plant Pathogens ◽  
Hydrophobic Interactions ◽  
Imidazole Ring ◽  
Dynamics Simulation ◽  
Catalytic Center ◽  
Colletotrichum Capsici ◽  
Botanical Pesticide ◽  
Fungal Plant Pathogens

Berberine is a promising botanical pesticide against fungal plant pathogens. However, whether berberine inhibits the invasion of fungal pathogen across plant surface remains unclear. Here we demonstrated that the enzyme activities of purified cutinase from fungal pathogen Colletotrichum capsici were partially inhibited in presence of berberine toward different substrates. Molecular dynamics simulation results suggested the rigidity of cutinase was decreased with berberine added into the system. Interestingly, aggregations of berberine to the catalytic center of cutinase were observed, and stronger hydrophobic interactions were detected between key residue His 208 and berberine with concentrations of berberine increased. More importantly, this hydrophobic interaction conferred conformational change of the imidazole ring of His 208, which swung out of the catalytic center to an inactive mode. In summary, we provided the molecular mechanism of the effect of berberine on cutinase from C. capsici.

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