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Bart P. H. J. Thomma - One of the best experts on this subject based on the ideXlab platform.
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Centromere evolution in the fungal genus Verticillium
bioRxiv, 2020Co-Authors: Michael F. Seidl, Martin Kramer, David Cook, Gabriel Lorencini Fiorin, Grardy C. M. Van Den Berg, Luigi Faino, Bart P. H. J. ThommaAbstract:Centromeres are chromosomal regions that are crucial for chromosome segregation during mitosis and meiosis, and failed centromere formation can contribute to chromosomal anomalies. Despite this conserved function, centromeres differ significantly between and even within species. Thus far, systematic studies into the organization and evolution of fungal centromeres remain scarce. In this study, we identified the centromeres in each of the ten species of the fungal genus Verticillium and characterized their organization and evolution. Chromatin immunoprecipitation of the centromere-specific histone CenH3 (ChIP-seq) and chromatin conformation capture (Hi-C) followed by high-throughput sequencing identified eight conserved, large (~150 kb), AT-, and repeat-rich regional centromeres that are embedded in heterochromatin in the plant pathogen V. dahliae. Using Hi-C, we similarly identified repeat-rich centromeres in the other Verticillium species. Strikingly, a single repetitive element is strongly associated with centromeric regions in some but not all Verticillium species. Extensive chromosomal rearrangements occurred during Verticillium evolution, yet only a minority could be linked to centromeres, suggesting that centromeres played a minor role in chromosomal evolution. Nevertheless, the size and organization of centromeres differ considerably between species, and centromere size was found to correlate with the genome-wide repeat content. Overall, our study highlights the contribution of repetitive elements to the diversity and rapid evolution of centromeres within the fungal genus Verticillium.
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Verticillium wilt caused by Verticillium dahliae in woody plants with emphasis on olive and shade trees
European Journal of Plant Pathology, 2018Co-Authors: Mojtaba Keykhasaber, Bart P. H. J. Thomma, Jelle A. HiemstraAbstract:Olive plantations and tree nurseries are economically and ecologically important agricultural sectors. However, Verticillium wilt, caused by Verticillium dahliae Kleb., is a serious problem in olive-growing regions and in tree nurseries worldwide. In this review we describe common and differentiating aspects of Verticillium wilts in some of the main economically woody hosts. The establishment of new planting sites on infested soils, the use of infected plant material and the spread of highly virulent pathogen isolates are the main reasons of increasing problems with Verticillium wilt in tree cultivation. Therefore, protocols for quick and efficient screening of new planting sites as well as planting material for V. dahliae prior to cultivation is an important measure to control Verticillium wilt disease. Furthermore, screening for resistant genotypes that can be included in breeding programs to increase resistance to Verticillium wilt is an important strategy for future disease control. Collectively, these strategies are essential tools in an integrated disease management strategy to control Verticillium wilt in tree plantations and nurseries.
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Verticillium longisporum the invisible threat to oilseed rape and other brassicaceous plant hosts
Molecular Plant Pathology, 2016Co-Authors: Jasper R L Depotter, Krishna V Subbarao, Silke Deketelaere, Patrik Inderbitzin, Andreas Von Tiedemann, Monica Hofte, Thomas A Wood, Bart P. H. J. ThommaAbstract:Introduction: The causal agents of Verticillium wilts are globally distributed pathogens that cause significant crop losses every year. Most Verticillium wilts are caused by V. dahliae, which is pathogenic on a broad range of plant hosts, whereas other pathogenic Verticillium species have more restricted host ranges. In contrast, V. longisporum appears to prefer brassicaceous plants and poses an increasing problem to oilseed rape production. Taxonomy: Kingdom Fungi; Phylum Ascomycota; Class Sordariomycetes; Subclass Hypocreomycetida; Family Plectosphaerellaceae; genus Verticillium. Disease symptoms: Dark unilateral stripes appear on the stems of apparently healthy looking oilseed rape plants at the end of the growing season. Microsclerotia are subsequently formed in the stem cortex beneath the epidermis. Genome: Verticillium longisporum is the only non-haploid species in the Verticillium genus, as it is an amphidiploid hybrid that carries almost twice as much genetic material as the other Verticillium species as a result of interspecific hybridization. Disease management: There is no effective fungicide treatment to control Verticillium diseases, and resistance breeding is the preferred strategy for disease management. However, only a few Verticillium wilt resistance genes have been identified, and monogenic resistance against V. longisporum has not yet been found. Quantitative resistance exists mainly in the Brassica C-genome of parental cabbage lines and may be introgressed in oilseed rape breeding lines. Common name: Oilseed rape colonized by V. longisporum does not develop wilting symptoms, and therefore the common name of Verticillium wilt is unsuitable for this crop. Therefore, we propose 'Verticillium stem striping' as the common name for Verticillium infections of oilseed rape.
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Verticillium alfalfae and V . dahliae , Agents of Verticillium Wilt Diseases
Genomics of Plant-Associated Fungi and Oomycetes: Dicot Pathogens, 2014Co-Authors: Patrik Inderbitzin, Bart P. H. J. Thomma, S. J. Klosterman, Krishna V SubbaraoAbstract:Verticillium dahliae and V. alfalfae (formerly Verticillium albo-atrum) are two important agricultural pathogens that affect many crops around the world and cause a distinct type of vascular wilt, which are known as Verticillium wilts. Several V. alfalfae and V. dahliae genomes have been sequenced, and are among the smaller genomes from filamentous ascomycetes. The number of predicted protein-encoding genes is similar to the saprobe Neurospora crassa. Perhaps reflective of their particular hemibiotrophic life styles, some gene families are expanded in the V. alfalfae and V. dahliae genomes. These include the gene families encoding glycoside hydrolases GH88, necrosis and ethylene-inducing-like proteins (NLPs), LysM effectors, proteins with chitin-recognition motifs, and cutinases. But the number of predicted secreted proteins was less than half that of the related Colletotrichum species, the agents of anthracnose diseases. V. dahliae strains generally contain lineage-specific regions (LS regions), which may play an important role in virulence and pathogenicity. Examples for horizontal transfer into Verticillium ancestors include the virulence factor Ave1, a glucan glucosyltransferase, and potentially some of the retrotransposons. The V. alfalfae and V. dahliae genomes have already had significant impacts on various aspects of basic and applied Verticillium research.
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interfamily transfer of tomato ve1 mediates Verticillium resistance in arabidopsis
Plant Physiology, 2011Co-Authors: Emilie F Fradin, Ahmed Abdelhaliem, Laura Masini, G C M Van Den Berg, M H A J Joosten, Bart P. H. J. ThommaAbstract:Vascular wilts caused by soil-borne fungal species of the Verticillium genus are devastating plant diseases. The most common species, Verticillium dahliae and Verticillium albo-atrum, have broad host ranges and are notoriously difficult to control. Therefore, genetic resistance is the preferred method for disease control. Only from tomato (Solanum lycopersicum) has a Verticillium resistance locus been cloned, comprising the Ve1 gene that encodes a receptor-like protein-type cell surface receptor. Due to lack of a suitable model for receptor-like protein (RLP)-mediated resistance signaling in Arabidopsis (Arabidopsis thaliana), so far relatively little is known about RLP signaling in pathogen resistance. Here, we show that Ve1 remains fully functional after interfamily transfer to Arabidopsis and that Ve1-transgenic Arabidopsis is resistant to race 1 but not to race 2 strains of V. dahliae and V. albo-atrum, nor to the Brassicaceae-specific pathogen Verticillium longisporum. Furthermore, we show that signaling components utilized by Ve1 in Arabidopsis to establish Verticillium resistance overlap with those required in tomato and include SERK3/BAK1, EDS1, and NDR1, which strongly suggests that critical components for resistance signaling are conserved. We subsequently investigated the requirement of SERK family members for Ve1 resistance in Arabidopsis, revealing that SERK1 is required in addition to SERK3/BAK1. Using virus-induced gene silencing, the requirement of SERK1 for Ve1-mediated resistance was confirmed in tomato. Moreover, we show the requirement of SERK1 for resistance against the foliar fungal pathogen Cladosporium fulvum mediated by the RLP Cf-4. Our results demonstrate that Arabidopsis can be used as model to unravel the genetics of Ve1-mediated resistance.
Krishna V Subbarao - One of the best experts on this subject based on the ideXlab platform.
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Assessment of Resistance in Potato Cultivars to Verticillium Wilt Caused by Verticillium dahliae and Verticillium nonalfalfae.
Plant Disease, 2019Co-Authors: Zhipeng Wang, Wenjing Shang, Ruiqing Shen, Chengjin Guo, Qingyun Guo, Krishna V SubbaraoAbstract:Verticillium wilt caused by Verticillium spp., also called potato early dying disease, is one of the most serious soilborne diseases affecting potato production in China. The disease has been expanding into most potato production areas over the past few years. Information on host resistance against Verticillium wilt among the potato cultivars in China is scarce, but it is critical for sustainable management of the disease. This study, therefore, evaluated 30 commercially popular potato cultivars against Verticillium dahliae strain Vdp83 and Verticillium nonalfalfae strain Vnp24, two well-characterized strains causing Verticillium wilt of potato in China. Both strains were isolated from diseased potato plants, and they were previously proven to be highly virulent. Ten plants of each cultivar were inoculated with the V. dahliae strain and incubated on greenhouse benches. Symptoms were rated at weekly intervals, and the relative area under the disease progress curve was calculated. The experiment was repeated once, and nonparametric analysis was used to calculate the relative marginal effects and the corresponding confidence intervals. Five resistant cultivars and four susceptible cultivars identified from the analyses were then challenged with the V. nonalfalfae strain. Cultivar responses to V. nonalfalfae were like those exhibited against V. dahliae, except for one cultivar. This study showed that resistance among potato cultivars exists in China against Verticillium spp. and that the resistance to V. dahliae identified in potato is also effective against the other Verticillium species that cause Verticillium wilt with a few exceptions. Cultivars identified as resistant to Verticillium wilt can be deployed to manage the disease until the breeding programs develop new cultivars with resistance from the sources identified in this study.
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A Review of Control Options and Externalities for Verticillium Wilts.
Phytopathology, 2017Co-Authors: Christine L. Carroll, Colin A. Carter, Rachael E. Goodhue, C.-y. Cynthia Lin Lawell, Krishna V SubbaraoAbstract:Plant pathogens migrate to new regions through human activities such as trade, where they may establish themselves and cause disease on agriculturally important crops. Verticillium wilt of lettuce, caused by Verticillium dahliae, is a soilborne fungus that was introduced to coastal California via infested spinach seeds. It has caused significant losses for lettuce growers. Once introduced, Verticillium wilt could be managed by fumigating with methyl bromide and chloropicrin, but this option is no longer available. Growers can also manage the disease by planting broccoli or not planting spinach. These control options require long-term investments for future gain. Verticillium wilt can also be prevented or controlled by testing and providing spinach seeds with little or no V. dahliae infestation. However, seed companies have been reluctant to test or clean spinach seeds, as spinach crops are not affected by Verticillium wilt. Thus, available control options are affected by externalities. Renters and other producers with short time horizons will not undertake long-term investments and seed companies do not take into account the effect of their decision not to test on lettuce producers. We review the literature on the economics of managing crop disease; discuss the economics of managing Verticillium wilt; and review the recent research on the externalities that arise with short-term growers, and between seed companies and growers due to Verticillium wilt. An externality arises whenever the actions of one individual or firm affects the payoffs to another individual or firm not involved in a specific transaction. These externalities have important implications for the management of Verticillium wilt and, more broadly, for the management of migratory pathogens and the diseases they cause in agriculture in general. This review is of interest to policy-makers, the producers, marketers, seed companies, and researchers.
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The economics of managing Verticillium wilt, an imported disease in California lettuce
California Agriculture, 2017Co-Authors: Christine L. Carroll, Colin A. Carter, Rachael E. Goodhue, C.-y. Cynthia Lin Lawell, Krishna V SubbaraoAbstract:Verticillium dahliae is a soilborne fungus that is introduced to the soil via infested spinach seeds and that causes lettuce to be afflicted with Verticillium wilt. This disease has spread rapidly through the Salinas Valley, the prime lettuce production region of California. Verticillium wilt can be prevented or controlled by the grower by fumigating, planting broccoli, or not planting spinach. Because these control options require long-term investment for future gain, renters might not take the steps needed to control Verticillium wilt. Verticillium wilt can also be prevented or controlled by a spinach seed company through testing and cleaning the spinach seeds. However, seed companies are unwilling to test or clean spinach seeds, as they are not affected by this disease. We discuss our research on the externalities that arise with renters, and between seed companies and growers, due to Verticillium wilt. These externalities have important implications for the management of Verticillium wilt in particular, and for the management of diseases in agriculture in general.
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Verticillium longisporum the invisible threat to oilseed rape and other brassicaceous plant hosts
Molecular Plant Pathology, 2016Co-Authors: Jasper R L Depotter, Krishna V Subbarao, Silke Deketelaere, Patrik Inderbitzin, Andreas Von Tiedemann, Monica Hofte, Thomas A Wood, Bart P. H. J. ThommaAbstract:Introduction: The causal agents of Verticillium wilts are globally distributed pathogens that cause significant crop losses every year. Most Verticillium wilts are caused by V. dahliae, which is pathogenic on a broad range of plant hosts, whereas other pathogenic Verticillium species have more restricted host ranges. In contrast, V. longisporum appears to prefer brassicaceous plants and poses an increasing problem to oilseed rape production. Taxonomy: Kingdom Fungi; Phylum Ascomycota; Class Sordariomycetes; Subclass Hypocreomycetida; Family Plectosphaerellaceae; genus Verticillium. Disease symptoms: Dark unilateral stripes appear on the stems of apparently healthy looking oilseed rape plants at the end of the growing season. Microsclerotia are subsequently formed in the stem cortex beneath the epidermis. Genome: Verticillium longisporum is the only non-haploid species in the Verticillium genus, as it is an amphidiploid hybrid that carries almost twice as much genetic material as the other Verticillium species as a result of interspecific hybridization. Disease management: There is no effective fungicide treatment to control Verticillium diseases, and resistance breeding is the preferred strategy for disease management. However, only a few Verticillium wilt resistance genes have been identified, and monogenic resistance against V. longisporum has not yet been found. Quantitative resistance exists mainly in the Brassica C-genome of parental cabbage lines and may be introgressed in oilseed rape breeding lines. Common name: Oilseed rape colonized by V. longisporum does not develop wilting symptoms, and therefore the common name of Verticillium wilt is unsuitable for this crop. Therefore, we propose 'Verticillium stem striping' as the common name for Verticillium infections of oilseed rape.
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Verticillium alfalfae and V . dahliae , Agents of Verticillium Wilt Diseases
Genomics of Plant-Associated Fungi and Oomycetes: Dicot Pathogens, 2014Co-Authors: Patrik Inderbitzin, Bart P. H. J. Thomma, S. J. Klosterman, Krishna V SubbaraoAbstract:Verticillium dahliae and V. alfalfae (formerly Verticillium albo-atrum) are two important agricultural pathogens that affect many crops around the world and cause a distinct type of vascular wilt, which are known as Verticillium wilts. Several V. alfalfae and V. dahliae genomes have been sequenced, and are among the smaller genomes from filamentous ascomycetes. The number of predicted protein-encoding genes is similar to the saprobe Neurospora crassa. Perhaps reflective of their particular hemibiotrophic life styles, some gene families are expanded in the V. alfalfae and V. dahliae genomes. These include the gene families encoding glycoside hydrolases GH88, necrosis and ethylene-inducing-like proteins (NLPs), LysM effectors, proteins with chitin-recognition motifs, and cutinases. But the number of predicted secreted proteins was less than half that of the related Colletotrichum species, the agents of anthracnose diseases. V. dahliae strains generally contain lineage-specific regions (LS regions), which may play an important role in virulence and pathogenicity. Examples for horizontal transfer into Verticillium ancestors include the virulence factor Ave1, a glucan glucosyltransferase, and potentially some of the retrotransposons. The V. alfalfae and V. dahliae genomes have already had significant impacts on various aspects of basic and applied Verticillium research.
Emilie F Fradin - One of the best experts on this subject based on the ideXlab platform.
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interfamily transfer of tomato ve1 mediates Verticillium resistance in arabidopsis
Plant Physiology, 2011Co-Authors: Emilie F Fradin, Ahmed Abdelhaliem, Laura Masini, G C M Van Den Berg, M H A J Joosten, Bart P. H. J. ThommaAbstract:Vascular wilts caused by soil-borne fungal species of the Verticillium genus are devastating plant diseases. The most common species, Verticillium dahliae and Verticillium albo-atrum, have broad host ranges and are notoriously difficult to control. Therefore, genetic resistance is the preferred method for disease control. Only from tomato (Solanum lycopersicum) has a Verticillium resistance locus been cloned, comprising the Ve1 gene that encodes a receptor-like protein-type cell surface receptor. Due to lack of a suitable model for receptor-like protein (RLP)-mediated resistance signaling in Arabidopsis (Arabidopsis thaliana), so far relatively little is known about RLP signaling in pathogen resistance. Here, we show that Ve1 remains fully functional after interfamily transfer to Arabidopsis and that Ve1-transgenic Arabidopsis is resistant to race 1 but not to race 2 strains of V. dahliae and V. albo-atrum, nor to the Brassicaceae-specific pathogen Verticillium longisporum. Furthermore, we show that signaling components utilized by Ve1 in Arabidopsis to establish Verticillium resistance overlap with those required in tomato and include SERK3/BAK1, EDS1, and NDR1, which strongly suggests that critical components for resistance signaling are conserved. We subsequently investigated the requirement of SERK family members for Ve1 resistance in Arabidopsis, revealing that SERK1 is required in addition to SERK3/BAK1. Using virus-induced gene silencing, the requirement of SERK1 for Ve1-mediated resistance was confirmed in tomato. Moreover, we show the requirement of SERK1 for resistance against the foliar fungal pathogen Cladosporium fulvum mediated by the RLP Cf-4. Our results demonstrate that Arabidopsis can be used as model to unravel the genetics of Ve1-mediated resistance.
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rna silencing is required for arabidopsis defence against Verticillium wilt disease
Journal of Experimental Botany, 2009Co-Authors: U Ellendorff, Emilie F Fradin, Ronnie De Jonge, Bart P. H. J. ThommaAbstract:RNA silencing is a conserved mechanism in eukaryotes that plays an important role in various biological processes including regulation of gene expression. RNA silencing also plays a role in genome stability and protects plants against invading nucleic acids such as transgenes and viruses. Recently, RNA silencing has been found to play a role in defence against bacterial plant pathogens in Arabidopsis through modulating host defence responses. In this study, it is shown that gene silencing plays a role in plant defence against multicellular microbial pathogens; vascular fungi belonging to the Verticillium genus. Several components of RNA silencing pathways were tested, of which many were found to affect Verticillium defence. Remarkably, no altered defence towards other fungal pathogens that include Alternaria brassicicola, Botrytis cinerea, and Plectosphaerella cucumerina, but also the vascular pathogen Fusarium oxysporum, was recorded. Since the observed differences in Verticillium susceptibility cannot be explained by notable differences in root architecture, it is speculated that the gene silencing mechanisms affect regulation of Verticillium-specific defence responses.
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physiology and molecular aspects of Verticillium wilt diseases caused by v dahliae and v albo atrum
Molecular Plant Pathology, 2006Co-Authors: Emilie F Fradin, Bart P. H. J. ThommaAbstract:Introduction: Verticillium spp. are soil-borne plant pathogens responsible for Verticillium wilt diseases in temperate and subtropical regions; collectively they affect over 200 hosts, including many economically important crops. There are currently no fungicides available to cure plants once they are infected. Taxonomy: Kingdom: Fungi, phylum: Ascomycota, subphylum, Pezizomycotina, class: Sordariomycetes, order: Phyllachorales, genus: Verticillium. Host range and disease symptoms: Over 200 mainly dicotyledonous species including herbaceous annuals, perennials and woody species are host to Verticillium diseases. As Verticillium symptoms can vary between hosts, there are no unique symptoms that belong to all plants infected by this fungus. Disease symptoms may comprise wilting, chlorosis, stunting, necrosis and vein clearing. Brown vascular discoloration may be observed in stem tissue cross-sections. Pathogenicity: Verticillium spp. have been reported to produce cell-wall-degrading enzymes and phytotoxins that all have been implicated in symptom development. Nevertheless, evidence for a crucial role of toxins in pathogenicity is inconsistent and therefore not generally accepted. Microsclerotia and melanized mycelium play an important role in the disease cycle as they are a major inoculum source and are the primary long-term survival structures. Resistance: Different defence responses in the prevascular and the vascular stage of Verticillium wilt diseases determine resistance. Although resistance physiology is well established, the molecular processes underlying this physiology remain largely unknown. Resistance against Verticillium largely depends on the isolation of the fungus in contained parts of the xylem tissues followed by subsequent elimination of the fungus. Although genetic resistance has been described in several plant species, only one resistance locus against Verticillium has been cloned to date.
Patrik Inderbitzin - One of the best experts on this subject based on the ideXlab platform.
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Verticillium longisporum the invisible threat to oilseed rape and other brassicaceous plant hosts
Molecular Plant Pathology, 2016Co-Authors: Jasper R L Depotter, Krishna V Subbarao, Silke Deketelaere, Patrik Inderbitzin, Andreas Von Tiedemann, Monica Hofte, Thomas A Wood, Bart P. H. J. ThommaAbstract:Introduction: The causal agents of Verticillium wilts are globally distributed pathogens that cause significant crop losses every year. Most Verticillium wilts are caused by V. dahliae, which is pathogenic on a broad range of plant hosts, whereas other pathogenic Verticillium species have more restricted host ranges. In contrast, V. longisporum appears to prefer brassicaceous plants and poses an increasing problem to oilseed rape production. Taxonomy: Kingdom Fungi; Phylum Ascomycota; Class Sordariomycetes; Subclass Hypocreomycetida; Family Plectosphaerellaceae; genus Verticillium. Disease symptoms: Dark unilateral stripes appear on the stems of apparently healthy looking oilseed rape plants at the end of the growing season. Microsclerotia are subsequently formed in the stem cortex beneath the epidermis. Genome: Verticillium longisporum is the only non-haploid species in the Verticillium genus, as it is an amphidiploid hybrid that carries almost twice as much genetic material as the other Verticillium species as a result of interspecific hybridization. Disease management: There is no effective fungicide treatment to control Verticillium diseases, and resistance breeding is the preferred strategy for disease management. However, only a few Verticillium wilt resistance genes have been identified, and monogenic resistance against V. longisporum has not yet been found. Quantitative resistance exists mainly in the Brassica C-genome of parental cabbage lines and may be introgressed in oilseed rape breeding lines. Common name: Oilseed rape colonized by V. longisporum does not develop wilting symptoms, and therefore the common name of Verticillium wilt is unsuitable for this crop. Therefore, we propose 'Verticillium stem striping' as the common name for Verticillium infections of oilseed rape.
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Verticillium alfalfae and V . dahliae , Agents of Verticillium Wilt Diseases
Genomics of Plant-Associated Fungi and Oomycetes: Dicot Pathogens, 2014Co-Authors: Patrik Inderbitzin, Bart P. H. J. Thomma, S. J. Klosterman, Krishna V SubbaraoAbstract:Verticillium dahliae and V. alfalfae (formerly Verticillium albo-atrum) are two important agricultural pathogens that affect many crops around the world and cause a distinct type of vascular wilt, which are known as Verticillium wilts. Several V. alfalfae and V. dahliae genomes have been sequenced, and are among the smaller genomes from filamentous ascomycetes. The number of predicted protein-encoding genes is similar to the saprobe Neurospora crassa. Perhaps reflective of their particular hemibiotrophic life styles, some gene families are expanded in the V. alfalfae and V. dahliae genomes. These include the gene families encoding glycoside hydrolases GH88, necrosis and ethylene-inducing-like proteins (NLPs), LysM effectors, proteins with chitin-recognition motifs, and cutinases. But the number of predicted secreted proteins was less than half that of the related Colletotrichum species, the agents of anthracnose diseases. V. dahliae strains generally contain lineage-specific regions (LS regions), which may play an important role in virulence and pathogenicity. Examples for horizontal transfer into Verticillium ancestors include the virulence factor Ave1, a glucan glucosyltransferase, and potentially some of the retrotransposons. The V. alfalfae and V. dahliae genomes have already had significant impacts on various aspects of basic and applied Verticillium research.
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Verticillium Systematics and Evolution: How Confusion Impedes Verticillium Wilt Management and How to Resolve It
Phytopathology, 2014Co-Authors: Patrik Inderbitzin, Krishna V SubbaraoAbstract:ABSTRACT Verticillium wilts are important vascular wilt diseases that affect many crops and ornamentals in different regions of the world. Verticillium wilts are caused by members of the ascomycete genus Verticillium, a small group of 10 species that are related to the agents of anthracnose caused by Colletotrichum species. Verticillium has a long and complicated taxonomic history with controversies about species boundaries and long overlooked cryptic species, which confused and limited our knowledge of the biology of individual species. We first review the taxonomic history of Verticillium, provide an update and explanation of the current system of classification and compile host range and geographic distribution data for individual species from internal transcribed spacer (ITS) GenBank records. Using Verticillium as an example, we show that species names are a poor vehicle for archiving and retrieving information, and that species identifications should always be backed up by DNA sequence data and DNA e...
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identification and differentiation of Verticillium species and v longisporum lineages by simplex and multiplex pcr assays
PLOS ONE, 2013Co-Authors: Patrik Inderbitzin, Michael R Davis, Richard M Bostock, Krishna V SubbaraoAbstract:Accurate species identification is essential for effective plant disease management, but is challenging in fungi including Verticillium sensu stricto (Ascomycota, Sordariomycetes, Plectosphaerellaceae), a small genus of ten species that includes important plant pathogens. Here we present fifteen PCR assays for the identification of all recognized Verticillium species and the three lineages of the diploid hybrid V. longisporum. The assays were based on DNA sequence data from the ribosomal internal transcribed spacer region, and coding and non-coding regions of actin, elongation factor 1-alpha, glyceraldehyde-3-phosphate dehydrogenase and tryptophan synthase genes. The eleven single target (simplex) PCR assays resulted in amplicons of diagnostic size for V. alfalfae, V. albo-atrum, V. dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii, V. nonalfalfae, V. nubilum, V. tricorpus, V. zaregamsianum, and Species A1 and Species D1, the two undescribed ancestors of V. longisporum. The four multiple target (multiplex) PCR assays simultaneously differentiated the species or lineages within the following four groups: Verticillium albo-atrum, V. alfalfae and V. nonalfalfae; Verticillium dahliae and V. longisporum lineages A1/D1, A1/D2 and A1/D3; Verticillium dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii and V. tricorpus; Verticillium isaacii, V. klebahnii and V. tricorpus. Since V. dahliae is a parent of two of the three lineages of the diploid hybrid V. longisporum, no simplex PCR assay is able to differentiate V. dahliae from all V. longisporum lineages. PCR assays were tested with fungal DNA extracts from pure cultures, and were not evaluated for detection and quantification of Verticillium species from plant or soil samples. The DNA sequence alignments are provided and can be used for the design of additional primers.
Jelle A. Hiemstra - One of the best experts on this subject based on the ideXlab platform.
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Verticillium wilt caused by Verticillium dahliae in woody plants with emphasis on olive and shade trees
European Journal of Plant Pathology, 2018Co-Authors: Mojtaba Keykhasaber, Bart P. H. J. Thomma, Jelle A. HiemstraAbstract:Olive plantations and tree nurseries are economically and ecologically important agricultural sectors. However, Verticillium wilt, caused by Verticillium dahliae Kleb., is a serious problem in olive-growing regions and in tree nurseries worldwide. In this review we describe common and differentiating aspects of Verticillium wilts in some of the main economically woody hosts. The establishment of new planting sites on infested soils, the use of infected plant material and the spread of highly virulent pathogen isolates are the main reasons of increasing problems with Verticillium wilt in tree cultivation. Therefore, protocols for quick and efficient screening of new planting sites as well as planting material for V. dahliae prior to cultivation is an important measure to control Verticillium wilt disease. Furthermore, screening for resistant genotypes that can be included in breeding programs to increase resistance to Verticillium wilt is an important strategy for future disease control. Collectively, these strategies are essential tools in an integrated disease management strategy to control Verticillium wilt in tree plantations and nurseries.
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The Arabidopsis thaliana DNA-binding protein AHL19 mediates Verticillium wilt resistance
Molecular Plant-Microbe Interactions, 2011Co-Authors: Koste A. Yadeta, Jelle A. Hiemstra, Mathieu Hanemian, Patrick Smit, Andy Pereira, Yves Marco, Bart P. H. J. ThommaAbstract:Verticillium spp. are destructive soilborne fungal pathogens that cause vascular wilt diseases in a wide range of plant species. Verticillium wilts are particularly notorious, and genetic resistance in crop plants is the most favorable means of disease control. In a gain-of-function screen using an activation-tagged Arabidopsis mutant collection, we identified four mutants, A1 to A4, which displayed enhanced resistance toward the vascular wilt species Verticillium dahliae, V. albo-atrum and V. longisporum but not to Fusarium oxysporum f. sp. raphani. Further testing revealed that mutant A2 displayed enhanced Ralstonia solanacearum resistance, while mutants A1 and A3 were more susceptible toward Pseudomonas syringae pv. tomato. Identification of the activation tag insertion site in the A1 mutant revealed an insertion in close proximity to the gene encoding AHL19, which was constitutively expressed in the mutant. AHL19 knock-out alleles were found to display enhanced Verticillium susceptibility whereas overexpression of AHL19 resulted in enhanced Verticillium resistance, showing that AHL19 acts as a positive regulator of plant defense.