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Michael J. Wingfield - One of the best experts on this subject based on the ideXlab platform.
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Phylogenomic incongruence in Ceratocystis: a clue to speciation?
BMC genomics, 2020Co-Authors: Aquillah M. Kanzi, Michael J. Wingfield, Irene Barnes, Magriet A. Van Der Nest, Conrad Trollip, Brenda D WingfieldAbstract:The taxonomic history of Ceratocystis, a genus in the Ceratocystidaceae, has been beset with questions and debate. This is due to many of the commonly used species recognition concepts (e.g., morphological and biological species concepts) providing different bases for interpretation of taxonomic boundaries. Species delineation in Ceratocystis primarily relied on genealogical concordance phylogenetic species recognition (GCPSR) using multiple standard molecular markers. Questions have arisen regarding the utility of these markers e.g., ITS, BT and TEF1-α due to evidence of intragenomic variation in the ITS, as well as genealogical incongruence, especially for isolates residing in a group referred to as the Latin-American clade (LAC) of the species. This study applied a phylogenomics approach to investigate the extent of phylogenetic incongruence in Ceratocystis. Phylogenomic analyses of a total of 1121 shared BUSCO genes revealed widespread incongruence within Ceratocystis, particularly within the LAC, which was typified by three equally represented topologies. Comparative analyses of the individual gene trees revealed evolutionary patterns indicative of hybridization. The maximum likelihood phylogenetic tree generated from the concatenated dataset comprised of 1069 shared BUSCO genes provided improved phylogenetic resolution suggesting the need for multiple gene markers in the phylogeny of Ceratocystis. The incongruence observed among single gene phylogenies in this study call into question the utility of single or a few molecular markers for species delineation. Although this study provides evidence of interspecific hybridization, the role of hybridization as the source of discordance will require further research because the results could also be explained by high levels of shared ancestral polymorphism in this recently diverged lineage. This study also highlights the utility of BUSCO genes as a set of multiple orthologous genes for phylogenomic studies.
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new Ceratocystis species associated with rapid death of metrosideros polymorpha in hawai i
Persoonia, 2018Co-Authors: Irene Barnes, Thomas C. Harrington, Michael J. Wingfield, Arista Fourie, L. S. Sugiyama, Doug Mcnew, Blaine Luiz, W P Heller, Lisa M. KeithAbstract:The native ˋōhiˋa lehua (Metrosideros polymorpha) has cultural, biological and ecological significance to Hawai`i, but it is seriously threatened by a disease commonly referred to as rapid ˋōhiˋa death (ROD). Preliminary investigations showed that a Ceratocystis species similar to C. fimbriata s.lat. was the cause of the disease. In this study, we used a combination of the phylogenetic, morphological and biological species concepts, as well as pathogenicity tests and microsatellite analyses, to characterise isolates collected from diseased ˋōhiˋa trees across Hawai`i Island. Two distinct lineages, representing new species of Ceratocystis, were evident based on multigene phylogenetic analyses. These are described here as C. lukuohia and C. huliohia. Ceratocystis lukuohia forms part of the Latin American clade (LAC) and was most closely associated with isolates from Syngonium and Xanthosoma from the Caribbean and elsewhere, including Hawai`i, and C. platani, which is native to eastern USA. Ceratocystis huliohia resides in the Asian-Australian clade (AAC) and is most closely related to C. uchidae, C. changhui and C. cercfabiensis, which are thought to be native to Asia. Morphology and interfertility tests support the delineation of these two new species and pathogenicity tests show that both species are aggressive pathogens on seedlings of M. polymorpha. Characterisation of isolates using microsatellite markers suggest that both species are clonal and likely represent recently-introduced strains. Intensive research is underway to develop rapid screening protocols for early detection of the pathogens and management strategies in an attempt to prevent the spread of the pathogens to the other islands of Hawai`i, which are currently disease free.
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Inheritance of phenotypic traits in the progeny of a Ceratocystis interspecific cross.
Fungal biology, 2018Co-Authors: Arista Fourie, Brenda D Wingfield, Michael J. Wingfield, Magriet A. Van Der Nest, M. Theodor Loots, Irene BarnesAbstract:Ceratocystis fimbriata is a fungal plant pathogen that causes black rot on Ipomoea batatas. Based on inoculation studies on numerous tree species, the pathogen is known to be host specific. The closely related species, Ceratocystis manginecans, causes severe wilt on a broad range of tree hosts, including Mangifera indica, Acacia mangium and other leguminous tree species. The genetic factors underlying the pathogenicity and host specificity of Ceratocystis species have rarely been investigated. In this study, an F1 population of 70 recombinant progeny from a cross between C. fimbriata and C. manginecans was generated and the inheritance of various phenotypic traits was investigated. Results showed that colony colour, growth rate, asexual spore production and aggressiveness to I. batatas and A. mangium are all quantitative traits with high levels of heritability. However, conidia production and aggressiveness appeared to be regulated by a small number of genes. No correlation could be found between aggressiveness and other phenotypic traits, suggesting that these are inherited independently. This is the first study to consider genetic inheritance of pathogenicity and host specificity in Ceratocystis species and the results will contribute, in future, to the identification of quantitative trait loci and candidate genes associated with the traits investigated.
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New Ceratocystis species from Eucalyptus and Cunninghamia in South China.
Antonie van Leeuwenhoek, 2015Co-Authors: Feifei Liu, Michael J. Wingfield, Jolanda Roux, Michael Mbenoun, Irene Barnes, Shuaifei ChenAbstract:During routine surveys for possible fungal pathogens in the rapidly expanding plantations of Eucalyptus and Cunninghamia lanceolata in China, numerous isolates of unknown species in the genus Ceratocystis (Microascales) were obtained from tree wounds. In this study we identified the Ceratocystis isolates from Eucalyptus and Cunninghamia in the GuangDong, GuangXi, FuJian and HaiNan Provinces of South China based on morphology and through comparisons of DNA sequence data for the ITS, partial β-tubulin and TEF-1α gene regions. Morphological and DNA sequence comparisons revealed two previously unknown species residing in the Indo-Pacific Clade. These are described here as Ceratocystis cercfabiensis sp. nov. and Ceratocystis collisensis sp. nov. Isolates of Ceratocystis cercfabiensis showed intragenomic variation in their ITS sequences and four strains were selected for cloning of the ITS gene region. Twelve ITS haplotypes were obtained from 17 clones selected for sequencing, differing in up to seven base positions and representing two separate phylogenetic groups. This is the first evidence of multiple ITS types in isolates of Ceratocystis residing in the Indo-Pacific Clade. Caution should thus be exercised when using the ITS gene region as a barcoding marker for Ceratocystis species in this clade. This study also represents the first record of a species of Ceratocystis from Cunninghamia.
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Molecular phylogenetic analyses reveal three new Ceratocystis species and provide evidence for geographic differentiation of the genus in Africa
Mycological Progress, 2014Co-Authors: Michael Mbenoun, Brenda D Wingfield, Michael J. Wingfield, Aimé D. Begoude Boyogueno, Jolanda RouxAbstract:The emergence of wattle wilt disease on non-native Acacia mearnsii trees in Africa, caused by the indigenous fungus Ceratocystis albifundus , has highlighted a need to better understand the diversity, ecology and distribution of Ceratocystis species in natural African environments. In this study we applied phylogenetic inference to identify and characterize isolates of Ceratocystis collected in a natural savanna ecosystem in South Africa. Three new species were recognized and are described as C. cryptoformis sp. nov. in the C. moniliformis complex, as well as C. thulamelensis sp. nov. and C. zambeziensis sp. nov., both residing in the C. fimbriata complex. Incorporating the new species into global phylogenies of Ceratocystis provided insights into the patterns of evolution and biogeography of this group of fungi. Notably, the African continent was identified as an important centre of diversification of Ceratocystis spp., from which several lineages of these fungi were shown to have radiated.
Brenda D Wingfield - One of the best experts on this subject based on the ideXlab platform.
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Phylogenomic incongruence in Ceratocystis: a clue to speciation?
BMC genomics, 2020Co-Authors: Aquillah M. Kanzi, Michael J. Wingfield, Irene Barnes, Magriet A. Van Der Nest, Conrad Trollip, Brenda D WingfieldAbstract:The taxonomic history of Ceratocystis, a genus in the Ceratocystidaceae, has been beset with questions and debate. This is due to many of the commonly used species recognition concepts (e.g., morphological and biological species concepts) providing different bases for interpretation of taxonomic boundaries. Species delineation in Ceratocystis primarily relied on genealogical concordance phylogenetic species recognition (GCPSR) using multiple standard molecular markers. Questions have arisen regarding the utility of these markers e.g., ITS, BT and TEF1-α due to evidence of intragenomic variation in the ITS, as well as genealogical incongruence, especially for isolates residing in a group referred to as the Latin-American clade (LAC) of the species. This study applied a phylogenomics approach to investigate the extent of phylogenetic incongruence in Ceratocystis. Phylogenomic analyses of a total of 1121 shared BUSCO genes revealed widespread incongruence within Ceratocystis, particularly within the LAC, which was typified by three equally represented topologies. Comparative analyses of the individual gene trees revealed evolutionary patterns indicative of hybridization. The maximum likelihood phylogenetic tree generated from the concatenated dataset comprised of 1069 shared BUSCO genes provided improved phylogenetic resolution suggesting the need for multiple gene markers in the phylogeny of Ceratocystis. The incongruence observed among single gene phylogenies in this study call into question the utility of single or a few molecular markers for species delineation. Although this study provides evidence of interspecific hybridization, the role of hybridization as the source of discordance will require further research because the results could also be explained by high levels of shared ancestral polymorphism in this recently diverged lineage. This study also highlights the utility of BUSCO genes as a set of multiple orthologous genes for phylogenomic studies.
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Inheritance of phenotypic traits in the progeny of a Ceratocystis interspecific cross.
Fungal biology, 2018Co-Authors: Arista Fourie, Brenda D Wingfield, Michael J. Wingfield, Magriet A. Van Der Nest, M. Theodor Loots, Irene BarnesAbstract:Ceratocystis fimbriata is a fungal plant pathogen that causes black rot on Ipomoea batatas. Based on inoculation studies on numerous tree species, the pathogen is known to be host specific. The closely related species, Ceratocystis manginecans, causes severe wilt on a broad range of tree hosts, including Mangifera indica, Acacia mangium and other leguminous tree species. The genetic factors underlying the pathogenicity and host specificity of Ceratocystis species have rarely been investigated. In this study, an F1 population of 70 recombinant progeny from a cross between C. fimbriata and C. manginecans was generated and the inheritance of various phenotypic traits was investigated. Results showed that colony colour, growth rate, asexual spore production and aggressiveness to I. batatas and A. mangium are all quantitative traits with high levels of heritability. However, conidia production and aggressiveness appeared to be regulated by a small number of genes. No correlation could be found between aggressiveness and other phenotypic traits, suggesting that these are inherited independently. This is the first study to consider genetic inheritance of pathogenicity and host specificity in Ceratocystis species and the results will contribute, in future, to the identification of quantitative trait loci and candidate genes associated with the traits investigated.
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draft genome sequences for Ceratocystis fagacearum c harringtonii grosmannia penicillata and huntiella bhutanensis
IMA fungus, 2016Co-Authors: Brenda D Wingfield, Magriet A Van Der Nest, Andi M Wilson, Runlei Chang, Markus P Wilken, Wilhelm Z De Beer, Tuan A. Duong, Emma Theodora Steenkamp, Almuth Hammerbacher, Kershney NaidooAbstract:Draft genomes for the fungi Ceratocystis fagacearum, C. harringtonii, Grosmannia penicillata, and Huntiella bhutanensis are presented. Ceratocystis fagacearum is a major causal agent of vascular wilt of oaks and other trees in the family Fagaceae. Ceratocystis harringtonii, previously known as C. populicola, causes disease in Populus species in the USA and Canada. Grosmannia penicillata is the causal agent of bluestain of sapwood on various conifers, including Picea spp. and Pinus spp. in Europe. Huntiella bhutanensis is a fungus in Ceratocystidaceae and known only in association with the bark beetle Ips schmutzenhorferi that infests Picea spinulosa in Bhutan. The availability of these genomes will facilitate further studies on these fungi.
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Molecular phylogenetic analyses reveal three new Ceratocystis species and provide evidence for geographic differentiation of the genus in Africa
Mycological Progress, 2014Co-Authors: Michael Mbenoun, Brenda D Wingfield, Michael J. Wingfield, Aimé D. Begoude Boyogueno, Jolanda RouxAbstract:The emergence of wattle wilt disease on non-native Acacia mearnsii trees in Africa, caused by the indigenous fungus Ceratocystis albifundus , has highlighted a need to better understand the diversity, ecology and distribution of Ceratocystis species in natural African environments. In this study we applied phylogenetic inference to identify and characterize isolates of Ceratocystis collected in a natural savanna ecosystem in South Africa. Three new species were recognized and are described as C. cryptoformis sp. nov. in the C. moniliformis complex, as well as C. thulamelensis sp. nov. and C. zambeziensis sp. nov., both residing in the C. fimbriata complex. Incorporating the new species into global phylogenies of Ceratocystis provided insights into the patterns of evolution and biogeography of this group of fungi. Notably, the African continent was identified as an important centre of diversification of Ceratocystis spp., from which several lineages of these fungi were shown to have radiated.
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Redefining Ceratocystis and allied genera
Studies in mycology, 2014Co-Authors: Z.w. De Beer, Tuan A. Duong, Brenda D Wingfield, Irene Barnes, Michael J. WingfieldAbstract:The genus Ceratocystis was established in 1890 and accommodates many important fungi. These include serious plant pathogens, significant insect symbionts and agents of timber degradation that result in substantial economic losses. Virtually since its type was described from sweet potatoes, the taxonomy of Ceratocystis has been confused and vigorously debated. In recent years, particulary during the last two decades, it has become very obvious that this genus includes a wide diversity of very different fungi. These have been roughly lumped together due to their similar morphological structures that have clearly evolved through convergent evolution linked to an insect-associated ecology. As has been true for many other groups of fungi, the emergence of DNA-based sequence data and associated phylogenetic inferences, have made it possible to robustly support very distinct boundaries defined by morphological characters and ecological differences. In this study, DNA-sequence data for three carefully selected gene regions (60S, LSU, MCM7) were generated for 79 species residing in the aggregate genus Ceratocystis sensu lato and these data were subjected to rigorous phylogenetic analyses. The results made it possible to distinguish seven major groups for which generic names have been chosen and descriptions either provided or emended. The emended genera included Ceratocystis sensu stricto, Chalaropsis, Endoconidiophora, Thielaviopsis, and Ambrosiella, while two new genera, Davidsoniella and Huntiella, were described. In total, 30 new combinations have been made. This major revision of the generic boundaries in the Ceratocystidaceae will simplify future treatments and work with an important group of fungi including distantly related species illogically aggregated under a single name.
Jolanda Roux - One of the best experts on this subject based on the ideXlab platform.
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New Ceratocystis species from Eucalyptus and Cunninghamia in South China.
Antonie van Leeuwenhoek, 2015Co-Authors: Feifei Liu, Michael J. Wingfield, Jolanda Roux, Michael Mbenoun, Irene Barnes, Shuaifei ChenAbstract:During routine surveys for possible fungal pathogens in the rapidly expanding plantations of Eucalyptus and Cunninghamia lanceolata in China, numerous isolates of unknown species in the genus Ceratocystis (Microascales) were obtained from tree wounds. In this study we identified the Ceratocystis isolates from Eucalyptus and Cunninghamia in the GuangDong, GuangXi, FuJian and HaiNan Provinces of South China based on morphology and through comparisons of DNA sequence data for the ITS, partial β-tubulin and TEF-1α gene regions. Morphological and DNA sequence comparisons revealed two previously unknown species residing in the Indo-Pacific Clade. These are described here as Ceratocystis cercfabiensis sp. nov. and Ceratocystis collisensis sp. nov. Isolates of Ceratocystis cercfabiensis showed intragenomic variation in their ITS sequences and four strains were selected for cloning of the ITS gene region. Twelve ITS haplotypes were obtained from 17 clones selected for sequencing, differing in up to seven base positions and representing two separate phylogenetic groups. This is the first evidence of multiple ITS types in isolates of Ceratocystis residing in the Indo-Pacific Clade. Caution should thus be exercised when using the ITS gene region as a barcoding marker for Ceratocystis species in this clade. This study also represents the first record of a species of Ceratocystis from Cunninghamia.
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Molecular phylogenetic analyses reveal three new Ceratocystis species and provide evidence for geographic differentiation of the genus in Africa
Mycological Progress, 2014Co-Authors: Michael Mbenoun, Brenda D Wingfield, Michael J. Wingfield, Aimé D. Begoude Boyogueno, Jolanda RouxAbstract:The emergence of wattle wilt disease on non-native Acacia mearnsii trees in Africa, caused by the indigenous fungus Ceratocystis albifundus , has highlighted a need to better understand the diversity, ecology and distribution of Ceratocystis species in natural African environments. In this study we applied phylogenetic inference to identify and characterize isolates of Ceratocystis collected in a natural savanna ecosystem in South Africa. Three new species were recognized and are described as C. cryptoformis sp. nov. in the C. moniliformis complex, as well as C. thulamelensis sp. nov. and C. zambeziensis sp. nov., both residing in the C. fimbriata complex. Incorporating the new species into global phylogenies of Ceratocystis provided insights into the patterns of evolution and biogeography of this group of fungi. Notably, the African continent was identified as an important centre of diversification of Ceratocystis spp., from which several lineages of these fungi were shown to have radiated.
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Ceratocystis species, including two new taxa, from Eucalyptus trees in South Africa
Australasian Plant Pathology, 2013Co-Authors: Gilbert Kamgan Nkuekam, Michael J. Wingfield, Jolanda RouxAbstract:The ascomycete genus Ceratocystis (Microascales, Ceratocystidaceae) includes important fungal pathogens of trees, including Eucalyptus species. Ceratocystis species and their Thielaviopsis asexual states are typically associated with insects, such as nitidulid beetles, that spread them over long distances. Eucalyptus trees comprise a substantial component of the forestry industry in South Africa, however, limited information is available regarding Ceratocystis species that infect these trees. In this study, Ceratocystis species were collected from wounds on Eucalyptus trees in all the major plantation regions of South Africa, as well as from insects associated with these wounds. Both morphology and multigene DNA sequence analyses, using three nuclear loci, were used to identify the Ceratocystis species. Of the 260 isolates collected, nine Ceratocystis species, of which two were represented only by their Thielaviopsis anamorph states were identified. These species were C. eucalypticola , C. pirilliformis , C. savannae , C. oblonga , C. moniliformis , T. basicola , T. thielavioides and two Ceratocystis species that are described here as C. salinaria sp. nov. and C. decipiens sp. nov. Insects associated with these Ceratocystis species were Brachypeplus depressus (Nitidulidae), Carpophylus bisignatus , C. dimidiatus (Nitidulidae), Xyleborus affinis (Scolytidae), Litargus sp. (Mycetophagidae) and a Staphylinid (Staphylinidae) species.
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Ceratocystis species, including two new taxa, from Eucalyptus trees in South Africa
Australasian Plant Pathology, 2013Co-Authors: Gilbert Kamgan Nkuekam, Michael J. Wingfield, Jolanda RouxAbstract:The ascomycete genus Ceratocystis (Microascales, Ceratocystidaceae) includes important fungal pathogens of trees, including Eucalyptus species. Ceratocystis species and their Thielaviopsis asexual states are typically associated with insects, such as nitidulid beetles, that spread them over long distances. Eucalyptus trees comprise a substantial component of the forestry industry in South Africa, however, limited information is available regarding Ceratocystis species that infect these trees. In this study, Ceratocystis species were collected from wounds on Eucalyptus trees in all the major plantation regions of South Africa, as well as from insects associated with these wounds. Both morphology and multigene DNA sequence analyses, using three nuclear loci, were used to identify the Ceratocystis species. Of the 260 isolates collected, nine Ceratocystis species, of which two were represented only by their Thielaviopsis anamorph states were identified. These species were C. eucalypticola , C. pirilliformis , C. savannae , C. oblonga , C. moniliformis , T. basicola , T. thielavioides and two Ceratocystis species that are described here as C. salinaria sp. nov. and C. decipiens sp. nov. Insects associated with these Ceratocystis species were Brachypeplus depressus (Nitidulidae), Carpophylus bisignatus , C. dimidiatus (Nitidulidae), Xyleborus affinis (Scolytidae), Litargus sp. (Mycetophagidae) and a Staphylinid (Staphylinidae) species.
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Ceratocystis species, including two new species associated with nitidulid beetles, on eucalypts in Australia
Antonie van Leeuwenhoek, 2012Co-Authors: Gilbert Kamgan Nkuekam, Michael J. Wingfield, Caroline Mohammed, Angus J. Carnegie, Geoff S. Pegg, Jolanda RouxAbstract:The genus Ceratocystis includes important fungal pathogens of trees, including Eucalyptus spp. Ironically, very little is known regarding the diversity or biology of Ceratocystis species on Eucalyptus species in Australia, where most of these trees are native. The aim of this study was to survey for Ceratocystis spp., and their possible insect associates, on eucalypts in Australia and thus to establish a foundation of knowledge regarding these fungi on the continent. Collections were made in three states of Australia from wounds on trees, as well as from nitidulid beetles associated with these wounds. Ceratocystis spp. were identified based on morphology and multigene sequence comparisons. Of the 54 isolates obtained, two previously unknown species of Ceratocystis were found and these are described here as Ceratocystis corymbiicola sp. nov. and Ceratocystis tyalla sp. nov. Furthermore, the distribution of Ceratocystis pirilliformis is expanded to include Eucalyptus spp. in Tasmania.
Acelino C Alfenas - One of the best experts on this subject based on the ideXlab platform.
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QTL mapping for resistance to Ceratocystis wilt in Eucalyptus
Tree Genetics & Genomes, 2016Co-Authors: Carla Cristina Gonçalves Rosado, L. M. Da S. Guimarães, Danielle A. Faria, Marcos Deon Vilela De Resende, Cosme Damião Cruz, Dario Grattapaglia, Acelino C AlfenasAbstract:Ceratocystis wilt caused by the fungus Ceratocystis fimbriata, is currently one of the major diseases in commercial plantations of Eucalyptus trees in Brazil. Deployment of resistant genotypes has been the main strategy for effective disease management. The present study aimed at identifying genomic regions underlying the genetic control of resistance to Ceratocystis wilt in Eucalyptus by quantitative trait loci (QTL) mapping in an outbred hybrid progeny derived from a cross between (Eucalyptus dunnii × Eucalyptus grandis) × (Eucalyptus urophylla × Eucalyptus globulus). A segregating population of 127 individuals was phenotyped for resistance to Ceratocystis wilt using controlled inoculation under a completely randomized design with five clonal replicates per individual plant. The phenotypic resistance response followed a continuous variation, enabling us to analyze the trait in a quantitative manner. The population was genotyped with 114 microsatellite markers and 110 were mapped with an average interval of 12.3 cM. Using a sib-pair interval-mapping approach five QTLs were identified for disease resistance, located on linkage groups 1, 3, 5, 8, and 10, and their estimated individual heritability ranged from 0.096 to 0.342. The QTL on linkage group 3 overlaps with other fungal disease-resistance QTLs mapped earlier and is consistent with the annotation of several disease-resistance genes on this chromosome in the E. grandis genome. This is the first study to identify and attempt to quantify the effects of QTLs associated with resistance to Ceratocystis wilt in Eucalyptus.
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Eucalyptus pellita as a source of resistance to rust, Ceratocystis wilt and leaf blight.
Cropp Breeding and Applied Biotechnology, 2010Co-Authors: L. M. Da S. Guimarães, M. Titon, Douglas Lau, Leonardo Novaes Rosse, Leonardo S. S. Oliveira, Carla Cristina Gonçalves Rosado, G. G. O. Christo, Acelino C AlfenasAbstract:Rust (Puccinia psidii), Ceratocystis wilt (Ceratocystis fimbriata) and cylindrocladium leaf blight (Cylindrocladium pteridis) are important diseases of eucalyptus. Planting of resistant genotypes is the most suitable control strategy of forest diseases under field condition. Resistance level of 23 Eucalyptus pellita clones was evaluated by artificial inoculations. Among the inoculated clones, 12 were resistant to rust, 16 to Ceratocystis wilt and 12 to cylindrocladium leaf blight, and three of them were resistant to all three diseases. The high intra-specific variability found in this study demonstrates the importance of E. pellita as a disease resistance source to be employed for introgression of novel resistance genes in eucalyptus genetic breeding programs.
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Ceratocystis Wilt of Cacao—A Disease of Increasing Importance
Phytopathology, 2007Co-Authors: Christine Engelbrecht, Thomas C. Harrington, Acelino C AlfenasAbstract:Engelbrecht, C. J., Harrington, T. C., and Alfenas, A. 2007. Ceratocystis wilt of cacao—A disease of increasing importance. Phytopathology 97: 1648-1649. Ceratocystis cacaofunesta (formerly C. fimbriata) causes a lethal wilt disease of cacao (Theobroma cacao) in the Caribbean and Central and South America. Recent studies employing phylogenetics, intersterility, and host range separate the cacao pathogen from other strains of the C. fimbriata complex. Ceratocystis wilt has been managed through genetic resistance, but the disease is an emerging problem in Bahia, Brazil, where it was recently introduced. Genetic studies indicate that populations of the fungus in Costa Rica, Colombia, and Bahia may have been introduced on cacao cuttings; whereas populations in Rondonia, Brazil, and western Ecuador appear to be native. The fungal genotype present in Bahia is similar to those found in Rondonia and may have been introduced on propagative material with witches’ broom resistance.
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annona squamosa a new host of Ceratocystis fimbriata
Fitopatologia Brasileira, 2006Co-Authors: Silvaldo Felipe Da Silveira, Thomas C. Harrington, Vicente Mussidias, Christine Engelbrecht, Acelino C Alfenas, Carolina R SilvaAbstract:Mango branch blight disease, caused by Ceratocystis fimbriata , is endemic to the municipality of Sao Fidelis in northern Rio de Janeiro State. In addition to mango, C. fimbriata was found associated with sugar apple trees (Annona squamosa) showing symptoms of branch blight in Sao Fidelis. Sugar apple and mango isolates from the same region had the same morphology and showed similar ITS-rDNA sequences. These sequences were also similar to other Brazilian isolates of C. fimbriata sensu stricto. Cross inoculation of such isolates obtained from diseased sugar apple and mango resulted in diseased symptoms on both plant species. This is the first record of A. squamosa as a host for C. fimbriata . Additional keywords: Host range, sugar apple, Mangifera indica, pathogenic variability. RESUMO Annona squamosa, nova hospedeira de Ceratocystis fimbriata . A seca-da-mangueira, causada pelo fungo Ceratocystis fimbriata , e uma doenca endemica no municipio de Sao Fidelis, no norte do Estado do Rio de Janeiro. Ceratocystis fimbriata foi encontrado associado a arvores de pinha (Annona squamosa) apresentando sintomas de seca dos ramos. Isolados obtidos de pinha e manga, originarios da mesma regiao, apresentaram a mesma morfologia e sequencias espacadoras ITS do rDNA similares. Estas sequencias foram tambem similares a de outros isolados brasileiros de C. fimbriata sensu stricto. Inoculacoes cruzadas dos isolados de pinha e manga resultaram no desenvolvimento de sintomas em ambas especies de plantas. Este e o primeiro relato de A. squamosa como hospedeira de C. fimbriata . Palavras-chave adicionais: Gama de hospedeiros, pinha, Mangifera indica, variabilidade patogenica.
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Genetic Variability and Host Specialization in the Latin American Clade of Ceratocystis fimbriata.
Phytopathology, 2003Co-Authors: Christine J. Baker, Thomas C. Harrington, Ulrike Krauss, Acelino C AlfenasAbstract:Baker, C. J., Harrington, T. C., Krauss, U., and Alfenas, A. C. 2003. Genetic variability and host specialization in the Latin American clade of Ceratocystis fimbriata. Phytopathology 93:1274-1284. The Ceratocystis fimbriata complex includes many undescribed species that cause wilt and canker diseases of many economically important plants. Phylogenetic analyses of DNA sequences have delineated three geographic clades within Ceratocystis fimbriata. This study examined host specialization in the Latin American clade, in which a number of lineages were identified using sequences of the internal transcribed spacer (ITS) region of the rDNA. Three host-associated lineages were identified from cacao (Theobroma cacao), sweet potato (Ipomoea batatas), and sycamore (Platanus spp.), respectively. Isolates from these three lineages showed strong host specialization in reciprocal inoculation experiments on these three hosts. Six cacao isolates from Ecuador, Trinidad, and Columbia differed genetically from other cacao isolates and were not pathogenic to cacao in inoculation tests. Further evidence of host specialization within the Latin American clade of Ceratocystis fimbriata was demonstrated in inoculation experiments in growth chambers using sweet potato, sycamore, Colocasia esculenta, coffee (Coffea arabica), and mango (Mangifera indica) plants; inoculation experiments in Brazil using Brazilian isolates from cacao, Eucalyptus spp., mango, and Gmelina arborea; and inoculation experiments in Costa Rica using Costa Rican isolates from cacao, coffee, and Xanthosoma sp. Hosts native to the Americas appeared to be colonized by only select pathogen genotypes, whereas nonnative hosts were colonized by several genotypes. We hypothesize that local populations of Ceratocystis fimbriata have specialized to different hosts; some of these populations are nascent species, and some host-specialized genotypes have been moved to new areas by humans.
Irene Barnes - One of the best experts on this subject based on the ideXlab platform.
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Phylogenomic incongruence in Ceratocystis: a clue to speciation?
BMC genomics, 2020Co-Authors: Aquillah M. Kanzi, Michael J. Wingfield, Irene Barnes, Magriet A. Van Der Nest, Conrad Trollip, Brenda D WingfieldAbstract:The taxonomic history of Ceratocystis, a genus in the Ceratocystidaceae, has been beset with questions and debate. This is due to many of the commonly used species recognition concepts (e.g., morphological and biological species concepts) providing different bases for interpretation of taxonomic boundaries. Species delineation in Ceratocystis primarily relied on genealogical concordance phylogenetic species recognition (GCPSR) using multiple standard molecular markers. Questions have arisen regarding the utility of these markers e.g., ITS, BT and TEF1-α due to evidence of intragenomic variation in the ITS, as well as genealogical incongruence, especially for isolates residing in a group referred to as the Latin-American clade (LAC) of the species. This study applied a phylogenomics approach to investigate the extent of phylogenetic incongruence in Ceratocystis. Phylogenomic analyses of a total of 1121 shared BUSCO genes revealed widespread incongruence within Ceratocystis, particularly within the LAC, which was typified by three equally represented topologies. Comparative analyses of the individual gene trees revealed evolutionary patterns indicative of hybridization. The maximum likelihood phylogenetic tree generated from the concatenated dataset comprised of 1069 shared BUSCO genes provided improved phylogenetic resolution suggesting the need for multiple gene markers in the phylogeny of Ceratocystis. The incongruence observed among single gene phylogenies in this study call into question the utility of single or a few molecular markers for species delineation. Although this study provides evidence of interspecific hybridization, the role of hybridization as the source of discordance will require further research because the results could also be explained by high levels of shared ancestral polymorphism in this recently diverged lineage. This study also highlights the utility of BUSCO genes as a set of multiple orthologous genes for phylogenomic studies.
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new Ceratocystis species associated with rapid death of metrosideros polymorpha in hawai i
Persoonia, 2018Co-Authors: Irene Barnes, Thomas C. Harrington, Michael J. Wingfield, Arista Fourie, L. S. Sugiyama, Doug Mcnew, Blaine Luiz, W P Heller, Lisa M. KeithAbstract:The native ˋōhiˋa lehua (Metrosideros polymorpha) has cultural, biological and ecological significance to Hawai`i, but it is seriously threatened by a disease commonly referred to as rapid ˋōhiˋa death (ROD). Preliminary investigations showed that a Ceratocystis species similar to C. fimbriata s.lat. was the cause of the disease. In this study, we used a combination of the phylogenetic, morphological and biological species concepts, as well as pathogenicity tests and microsatellite analyses, to characterise isolates collected from diseased ˋōhiˋa trees across Hawai`i Island. Two distinct lineages, representing new species of Ceratocystis, were evident based on multigene phylogenetic analyses. These are described here as C. lukuohia and C. huliohia. Ceratocystis lukuohia forms part of the Latin American clade (LAC) and was most closely associated with isolates from Syngonium and Xanthosoma from the Caribbean and elsewhere, including Hawai`i, and C. platani, which is native to eastern USA. Ceratocystis huliohia resides in the Asian-Australian clade (AAC) and is most closely related to C. uchidae, C. changhui and C. cercfabiensis, which are thought to be native to Asia. Morphology and interfertility tests support the delineation of these two new species and pathogenicity tests show that both species are aggressive pathogens on seedlings of M. polymorpha. Characterisation of isolates using microsatellite markers suggest that both species are clonal and likely represent recently-introduced strains. Intensive research is underway to develop rapid screening protocols for early detection of the pathogens and management strategies in an attempt to prevent the spread of the pathogens to the other islands of Hawai`i, which are currently disease free.
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Inheritance of phenotypic traits in the progeny of a Ceratocystis interspecific cross.
Fungal biology, 2018Co-Authors: Arista Fourie, Brenda D Wingfield, Michael J. Wingfield, Magriet A. Van Der Nest, M. Theodor Loots, Irene BarnesAbstract:Ceratocystis fimbriata is a fungal plant pathogen that causes black rot on Ipomoea batatas. Based on inoculation studies on numerous tree species, the pathogen is known to be host specific. The closely related species, Ceratocystis manginecans, causes severe wilt on a broad range of tree hosts, including Mangifera indica, Acacia mangium and other leguminous tree species. The genetic factors underlying the pathogenicity and host specificity of Ceratocystis species have rarely been investigated. In this study, an F1 population of 70 recombinant progeny from a cross between C. fimbriata and C. manginecans was generated and the inheritance of various phenotypic traits was investigated. Results showed that colony colour, growth rate, asexual spore production and aggressiveness to I. batatas and A. mangium are all quantitative traits with high levels of heritability. However, conidia production and aggressiveness appeared to be regulated by a small number of genes. No correlation could be found between aggressiveness and other phenotypic traits, suggesting that these are inherited independently. This is the first study to consider genetic inheritance of pathogenicity and host specificity in Ceratocystis species and the results will contribute, in future, to the identification of quantitative trait loci and candidate genes associated with the traits investigated.
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New Ceratocystis species from Eucalyptus and Cunninghamia in South China.
Antonie van Leeuwenhoek, 2015Co-Authors: Feifei Liu, Michael J. Wingfield, Jolanda Roux, Michael Mbenoun, Irene Barnes, Shuaifei ChenAbstract:During routine surveys for possible fungal pathogens in the rapidly expanding plantations of Eucalyptus and Cunninghamia lanceolata in China, numerous isolates of unknown species in the genus Ceratocystis (Microascales) were obtained from tree wounds. In this study we identified the Ceratocystis isolates from Eucalyptus and Cunninghamia in the GuangDong, GuangXi, FuJian and HaiNan Provinces of South China based on morphology and through comparisons of DNA sequence data for the ITS, partial β-tubulin and TEF-1α gene regions. Morphological and DNA sequence comparisons revealed two previously unknown species residing in the Indo-Pacific Clade. These are described here as Ceratocystis cercfabiensis sp. nov. and Ceratocystis collisensis sp. nov. Isolates of Ceratocystis cercfabiensis showed intragenomic variation in their ITS sequences and four strains were selected for cloning of the ITS gene region. Twelve ITS haplotypes were obtained from 17 clones selected for sequencing, differing in up to seven base positions and representing two separate phylogenetic groups. This is the first evidence of multiple ITS types in isolates of Ceratocystis residing in the Indo-Pacific Clade. Caution should thus be exercised when using the ITS gene region as a barcoding marker for Ceratocystis species in this clade. This study also represents the first record of a species of Ceratocystis from Cunninghamia.
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Redefining Ceratocystis and allied genera
Studies in mycology, 2014Co-Authors: Z.w. De Beer, Tuan A. Duong, Brenda D Wingfield, Irene Barnes, Michael J. WingfieldAbstract:The genus Ceratocystis was established in 1890 and accommodates many important fungi. These include serious plant pathogens, significant insect symbionts and agents of timber degradation that result in substantial economic losses. Virtually since its type was described from sweet potatoes, the taxonomy of Ceratocystis has been confused and vigorously debated. In recent years, particulary during the last two decades, it has become very obvious that this genus includes a wide diversity of very different fungi. These have been roughly lumped together due to their similar morphological structures that have clearly evolved through convergent evolution linked to an insect-associated ecology. As has been true for many other groups of fungi, the emergence of DNA-based sequence data and associated phylogenetic inferences, have made it possible to robustly support very distinct boundaries defined by morphological characters and ecological differences. In this study, DNA-sequence data for three carefully selected gene regions (60S, LSU, MCM7) were generated for 79 species residing in the aggregate genus Ceratocystis sensu lato and these data were subjected to rigorous phylogenetic analyses. The results made it possible to distinguish seven major groups for which generic names have been chosen and descriptions either provided or emended. The emended genera included Ceratocystis sensu stricto, Chalaropsis, Endoconidiophora, Thielaviopsis, and Ambrosiella, while two new genera, Davidsoniella and Huntiella, were described. In total, 30 new combinations have been made. This major revision of the generic boundaries in the Ceratocystidaceae will simplify future treatments and work with an important group of fungi including distantly related species illogically aggregated under a single name.