Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 186
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
Plant Dis ; 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38468134

RESUMO

Field surveys conducted during 2021 and 2022 in Western Sicily, Italy, revealed the presence of common fig trees severely affected by trunk and crown root canker and bark cracking. Moreover, in conjunction with the symptomatic tissues, the same surveyed plants showed the presence of bark beetle holes and internal wood galleries. The predominant beetle Criphalus dilutus was previously reported attacking figs in Sicily. Phylogenetic analyses based on multi-locus DNA data showed the presence of different fungal taxa associated with disease symptoms, including Botryosphaeria dothidea, Ceratocystis ficicola, Diaporthe foeniculina, Neocosmospora bostrycoides, N. perseae and Neofusicoccum luteum. Pathogenicity tests conducted on potted fig plants showed that all the species were pathogenic to fig, with C. ficicola and Neocosmospora spp. as the most aggressive fungal species. Moreover, isolations conducted from the bodies of emerging adult insects recovered from disease samples confirmed the presence of C. ficicola and Neocosmospora spp., suggesting the potential involvement of C. dilutus in their dissemination.

3.
Genome Biol Evol ; 15(1)2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36617272

RESUMO

Improved sequencing technologies have profoundly altered global views of fungal diversity and evolution. High-throughput sequencing methods are critical for studying fungi due to the cryptic, symbiotic nature of many species, particularly those that are difficult to culture. However, the low coverage genome sequencing (LCGS) approach to phylogenomic inference has not been widely applied to fungi. Here we analyzed 171 Kickxellomycotina fungi using LCGS methods to obtain hundreds of marker genes for robust phylogenomic reconstruction. Additionally, we mined our LCGS data for a set of nine rDNA and protein coding genes to enable analyses across species for which no LCGS data were obtained. The main goals of this study were to: 1) evaluate the quality and utility of LCGS data for both phylogenetic reconstruction and functional annotation, 2) test relationships among clades of Kickxellomycotina, and 3) perform comparative functional analyses between clades to gain insight into putative trophic modes. In opposition to previous studies, our nine-gene analyses support two clades of arthropod gut dwelling species and suggest a possible single evolutionary event leading to this symbiotic lifestyle. Furthermore, we resolve the mycoparasitic Dimargaritales as the earliest diverging clade in the subphylum and find four major clades of Coemansia species. Finally, functional analyses illustrate clear variation in predicted carbohydrate active enzymes and secondary metabolites (SM) based on ecology, that is biotroph versus saprotroph. Saprotrophic Kickxellales broadly lack many known pectinase families compared with saprotrophic Mucoromycota and are depauperate for SM but have similar numbers of predicted chitinases as mycoparasitic.


Assuntos
Artrópodes , Fungos , Humanos , Animais , Filogenia , Fungos/genética , Artrópodes/genética , Sequência de Bases , Genoma
4.
Plant Dis ; 2022 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-36383995

RESUMO

Clematis L. is one of the largest genera of Ranunculaceae, accommodating over 300 plant species (Wang & Li 2005). They are mostly flowering creepers commonly grown as ornamentals. Clematis leaf spot and wilt is a fungal disease caused by Calophoma clematidina (Thüm.) Q. Chen & L. Cai. Infected plants initially show irregular brown to black leaf spots which later turn into large necroses, usually leading to wilt disease. In June 2021, Clematis plants displaying symptoms described above were observed in three independent nurseries located in three counties (Brno-venkov, Breclav and Nymburk) in the Czech Republic. Around 60% of 120 inspected plants were symptomatic, including both mother plants and young plants. Leaves, stems and roots of 43 diseased plants originating from the three nurseries were collected, sectioned into small pieces (5 × 5 mm), surface sterilized (60 sec in 75% ethanol, followed by 60 sec in 1% sodium hypochlorite and rinsed three times using sterile distilled water), plated on potato dextrose agar (PDA) and incubated at 25°C for 5 weeks. Newly developed mycelia were immediately transferred to a fresh PDA plates and purified by single-spore isolation. A total of 21 strains morphologically resembled the genus Calophoma. Colonies on PDA (7 d at 25°C) were felty, white to olivaceous/iron grey in the centre. Conidiomata were dark brown, pycnidial, solitary or in groups, (117-220 × 65-170 µm). Conidia were cylindrical to ellipsoidal, hyaline, 0(-1)-septate, (4-8 × 2-3 µm). Two representative isolates were deposited at the Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands (CBS 149230 and CBS 149231). The partial internal transcribed spacer (ITS) regions, large ribosomal subunit of the nrRNA gene (LSU), beta-tubulin gene (tub2) and RNA polymerase II second largest subunit gene (rpb2) were amplified from genomic DNA of both isolates following protocols previously described (Spetik et al. 2022). Sequences were deposited in NCBI GenBank (accession nos. ITS: ON107539, ON107540; LSU: ON108575, ON108576; tub2: ON314832, ON314833; rpb2: ON125007, ON125008), being 100% identical with that of the ex-type strain of C. clematidina (CBS 108.79), ITS (NR_135964), LSU (FJ515632), tub2 (FJ427100), and rpb2 (KT389588). Phylogenetically, the two representative isolates formed a fully supported clade with sequences of the ex-type and another culture of C. clematidina in the multigene phylogeny. To confirm Koch's postulates, leaves of ten two-month-old Clematis plants grown in pots were wounded by a needle and inoculated with a conidial suspension (1.0 × 106 conidia ml-1) of both strains (five plants per strain) following Golazar et al. (2011). Ten plants were mock-inoculated with sterile distilled water and served as controls. Within one month, inoculated plants exhibited dark necrotic leaf spots similar to the symptoms observed in the nurseries, while controls remained symptomless. Calophoma clematidina was reisolated from the inoculated plants, and its identity confirmed (ITS, GenBank OP363927). The experiment was repeated. Although known from Europe, this is the first report of Clematis leaf spot and wilt caused by C. clematidina in the Czech Republic. Clematis leaf spot and wilt represents a serious disease in Czech nurseries, with the pathogen present in leaves, stems and roots of Clematis spp.

5.
G3 (Bethesda) ; 12(5)2022 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-35311955

RESUMO

Members of the fungal genus Phyllosticta can colonize a variety of plant hosts, including several Citrus species such as Citrus sinensis (orange), Citrus limon (lemon), and Citrus maxima (pomelo). Some Phyllosticta species have the capacity to cause disease, such as Citrus Black Spot, while others have only been observed as endophytes. Thus far, genomic differences underlying lifestyle adaptations of Phyllosticta species have not yet been studied. Furthermore, the lifestyle of Phyllosticta citrichinaensis is ambiguous, as it has been described as a weak pathogen but Koch's postulates may not have been established and the presence of this species was never reported to cause any crop or economic losses. Here, we examined the genomic differences between pathogenic and endophytic Phyllosticta spp. colonizing Citrus and specifically aimed to elucidate the lifestyle of Phyllosticta citrichinaensis. We found several genomic differences between species of different lifestyles, including groups of genes that were only present in pathogens or endophytes. We also observed that species, based on their carbohydrate active enzymes, group independent of their phylogenetic association, and this clustering correlated with trophy prediction. Phyllosticta citrichinaensis shows an intermediate lifestyle, sharing genomic and phenotypic attributes of both pathogens and endophytes. We thus present the first genomic comparison of multiple citrus-colonizing pathogens and endophytes of the genus Phyllosticta, and therefore provide the basis for further comparative studies into the lifestyle adaptations within this genus.


Assuntos
Ascomicetos , Citrus , Ascomicetos/genética , Citrus/genética , Citrus/microbiologia , Endófitos/genética , Genômica , Filogenia , Doenças das Plantas/microbiologia
6.
J Fungi (Basel) ; 7(12)2021 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-34947025

RESUMO

Symbiosis between insects and fungi arose multiple times during the evolution of both groups, and some of the most biologically diverse and economically important are mutualisms in which the insects cultivate and feed on fungi. Among these are bark beetles, whose ascomycetous cultivars are better known and studied than their frequently-overlooked and poorly understood basidiomycetous partners. In this study, we propose five new species of Entomocorticium, fungal mutualists in the Russulales (Basidiomycota) that are mutualistic symbionts of scolytine beetles. We have isolated these fungi from the beetle mycangia, which are structures adapted for the selective storage and transportation of fungal mutualists. Herein, we present the most complete phylogeny of the closely related genera Entomocorticium and Peniophora and provide insights into how an insect-associated taxon (Entomocorticium) evolved from within a wood-decaying, wind-dispersed lineage (Peniophora). Our results indicate that following a transition from angiosperms to gymnosperms, fungal domestication by beetles facilitated the evolution and diversification of Entomocorticium. We additionally propose four new species: Entomocorticium fibulatum Araújo, Li & Hulcr, sp. nov.; E. belizense Araújo, Li & Hulcr, sp. nov.; E. perryae Araújo, Li & Hulcr, sp. nov.; and E. macrovesiculatum Araújo, Li, Six & Hulcr, sp. nov. Our findings highlight the fact that insect-fungi associations remain an understudied field and that these associations harbor a large reservoir of novel fungal species.

7.
Front Microbiol ; 12: 737541, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34803952

RESUMO

The genus Botryosphaeria includes more than 200 epithets, but only the type species, Botryosphaeria dothidea and a dozen or more other species have been identified based on DNA sequence data. The taxonomic status of the other species remains unconfirmed because they lack either morphological information or DNA sequence data. In this study, types or authentic specimens of 16 "Botryosphaeria" species are reassessed to clarify their identity and phylogenetic position. nuDNA sequences of four regions, ITS, LSU, tef1-α and tub2, are analyzed and considered in combination with morphological characteristics. Based on the multigene phylogeny and morphological characters, Botryosphaeria cruenta and Botryosphaeria hamamelidis are transferred to Neofusicoccum. The generic status of Botryosphaeria aterrima and Botryosphaeria mirabile is confirmed in Botryosphaeria. Botryosphaeria berengeriana var. weigeliae and B. berengeriana var. acerina are treated synonyms of B. dothidea. Botryosphaeria mucosa is transferred to Neodeightonia as Neodeightonia mucosa, and Botryosphaeria ferruginea to Nothophoma as Nothophoma ferruginea. Botryosphaeria foliicola is reduced to synonymy with Phyllachorella micheliae. Botryosphaeria abuensis, Botryosphaeria aesculi, Botryosphaeria dasylirii, and Botryosphaeria wisteriae are tentatively kept in Botryosphaeria sensu stricto until further phylogenetic analysis is carried out on verified specimens. The ordinal status of Botryosphaeria apocyni, Botryosphaeria gaubae, and Botryosphaeria smilacinina cannot be determined, and tentatively accommodate these species in Dothideomycetes incertae sedis. The study demonstrates the significance of a polyphasic approach in characterizing type specimens, including the importance of using of DNA sequence data.

8.
Fungal Biol ; 125(10): 815-825, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34537177

RESUMO

The genus Phyllosticta includes both endophytic and phytopathogenic species that occur on a broad range of plant hosts, including Citrus. Some pathogenic species cause severe disease, such as Phyllosticta citricarpa, the causal agent of Citrus Black Spot (CBS). In contrast, other species, such as Phyllosticta capitalensis, have an endophytic lifestyle in numerous plant hosts. Carbon utilization capabilities are hypothesized to influence both host range and lifestyle, and are in part determined by the set of Carbohydrate Active Enzyme (CAZyme) encoding genes of a species. In this study, carbon utilization capabilities of five Phyllosticta species were determined, as well as the CAZyme repertoire (CAZome) encoded in their genomes. Little variation was found among species in terms of carbon utilization capabilities and CAZome. However, one of the tested carbon sources, sugar beet pulp (SBP), inhibited growth of the plant pathogens, also when combined with another carbon source, while endophytic species remained unaffected.


Assuntos
Citrus , Ascomicetos , Carbono , Doenças das Plantas
9.
IMA Fungus ; 12(1): 21, 2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34372938

RESUMO

Marine fungi remain poorly covered in global genome sequencing campaigns; the 1000 fungal genomes (1KFG) project attempts to shed light on the diversity, ecology and potential industrial use of overlooked and poorly resolved fungal taxa. This study characterizes the genomes of three marine fungi: Emericellopsis sp. TS7, wood-associated Amylocarpus encephaloides and algae-associated Calycina marina. These species were genome sequenced to study their genomic features, biosynthetic potential and phylogenetic placement using multilocus data. Amylocarpus encephaloides and C. marina were placed in the Helotiaceae and Pezizellaceae (Helotiales), respectively, based on a 15-gene phylogenetic analysis. These two genomes had fewer biosynthetic gene clusters (BGCs) and carbohydrate active enzymes (CAZymes) than Emericellopsis sp. TS7 isolate. Emericellopsis sp. TS7 (Hypocreales, Ascomycota) was isolated from the sponge Stelletta normani. A six-gene phylogenetic analysis placed the isolate in the marine Emericellopsis clade and morphological examination confirmed that the isolate represents a new species, which is described here as E. atlantica. Analysis of its CAZyme repertoire and a culturing experiment on three marine and one terrestrial substrates indicated that E. atlantica is a psychrotrophic generalist fungus that is able to degrade several types of marine biomass. FungiSMASH analysis revealed the presence of 35 BGCs including, eight non-ribosomal peptide synthases (NRPSs), six NRPS-like, six polyketide synthases, nine terpenes and six hybrid, mixed or other clusters. Of these BGCs, only five were homologous with characterized BGCs. The presence of unknown BGCs sets and large CAZyme repertoire set stage for further investigations of E. atlantica. The Pezizellaceae genome and the genome of the monotypic Amylocarpus genus represent the first published genomes of filamentous fungi that are restricted in their occurrence to the marine habitat and form thus a valuable resource for the community that can be used in studying ecological adaptions of fungi using comparative genomics.

10.
IMA Fungus ; 12(1): 11, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33934723

RESUMO

It is now a decade since The International Commission on the Taxonomy of Fungi (ICTF) produced an overview of requirements and best practices for describing a new fungal species. In the meantime the International Code of Nomenclature for algae, fungi, and plants (ICNafp) has changed from its former name (the International Code of Botanical Nomenclature) and introduced new formal requirements for valid publication of species scientific names, including the separation of provisions specific to Fungi and organisms treated as fungi in a new Chapter F. Equally transformative have been changes in the data collection, data dissemination, and analytical tools available to mycologists. This paper provides an updated and expanded discussion of current publication requirements along with best practices for the description of new fungal species and publication of new names and for improving accessibility of their associated metadata that have developed over the last 10 years. Additionally, we provide: (1) model papers for different fungal groups and circumstances; (2) a checklist to simplify meeting (i) the requirements of the ICNafp to ensure the effective, valid and legitimate publication of names of new taxa, and (ii) minimally accepted standards for description; and, (3) templates for preparing standardized species descriptions.

12.
Nat Microbiol ; 6(5): 540-548, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33903746

RESUMO

The identification and proper naming of microfungi, in particular plant, animal and human pathogens, remains challenging. Molecular identification is becoming the default approach for many fungal groups, and environmental metabarcoding is contributing an increasing amount of sequence data documenting fungal diversity on a global scale. This includes lineages represented only by sequence data. At present, these taxa cannot be formally described under the current nomenclature rules. By considering approaches used in bacterial taxonomy, we propose solutions for the nomenclature of taxa known only from sequences to facilitate consistent reporting and communication in the literature and public sequence repositories.


Assuntos
Fungos/classificação , Fungos/isolamento & purificação , Animais , DNA Fúngico/genética , Microbiologia Ambiental , Fungos/genética , Humanos , Micoses/microbiologia , Doenças das Plantas/microbiologia , Análise de Sequência de DNA , Terminologia como Assunto
13.
Pest Manag Sci ; 77(7): 3273-3288, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33764651

RESUMO

BACKGROUND: Pseudocercospora fijiensis is the causal agent of the black leaf streak disease (BLSD) of banana. Bananas are important global export commodities and a major staple food. Their susceptibility to BLSD pushes disease management towards excessive fungicide use, largely relying on multisite inhibitors and sterol demethylation inhibitors (DMIs). These fungicides are ubiquitous in plant disease control, targeting the CYP51 enzyme. We examined sensitivity to DMIs in P. fijiensis field isolates collected from various major banana production zones in Colombia, Costa Rica, Dominican Republic, Ecuador, the Philippines, Guadalupe, Martinique and Cameroon and determined the underlying genetic reasons for the observed phenotypes. RESULTS: We observed a continuous range of sensitivity towards the DMI fungicides difenoconazole, epoxiconazole and propiconazole with clear cross-sensitivity. Sequence analyses of PfCYP51 in 266 isolates showed 28 independent amino acid substitutions, nine of which correlated with reduced sensitivity to DMIs. In addition to the mutations, we observed up to six insertions in the Pfcyp51 promoter. Such promoter insertions contain repeated elements with a palindromic core and correlate with the enhanced expression of Pfcyp51 and hence with reduced DMI sensitivity. Wild-type isolates from unsprayed bananas fields did not contain any promoter insertions. CONCLUSION: The presented data significantly contribute to understanding of the evolution and global distribution of DMI resistance mechanisms in P. fijiensis field populations and facilitate the prediction of different DMI efficacy. The overall reduced DMI sensitivity calls for the deployment of a wider range of solutions for sustainable control of this major banana disease. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Fungicidas Industriais , Musa , Ascomicetos , Camarões , Colômbia , Costa Rica , Fungicidas Industriais/farmacologia , Filipinas
14.
J Fungi (Basel) ; 7(1)2021 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-33445649

RESUMO

Colletotrichum spp. are important pathogens of citrus that cause dieback of branches and postharvest disease. Globally, several species of Colletotrichum have been identified as causing anthracnose of citrus. One hundred and sixty-eight Colletotrichum isolates were collected from anthracnose symptoms on citrus stems, leaves, and fruit from Victoria, New South Wales, and Queensland, and from State herbaria in Australia. Colletotrichum australianum sp. nov., C. fructicola, C. gloeosporioides, C. karstii, C. siamense, and C. theobromicola were identified using multi-gene phylogenetic analyses based on seven genomic loci (ITS, gapdh, act, tub2, ApMat, gs, and chs-1) in the gloeosporioides complex and five genomic loci (ITS, tub2, act, chs-1, and his3) in the boninense complex, as well as morphological characters. Several isolates pathogenic to chili (Capsicum annuum), previously identified as C. queenslandicum, formed a clade with the citrus isolates described here as C. australianum sp. nov. The spore shape and culture characteristics of the chili and citrus isolates of C. australianum were similar and differed from those of C. queenslandicum. This is the first report of C. theobromicola isolated from citrus and the first detection of C. karstii and C. siamense associated with citrus anthracnose in Australia.

15.
Phytopathology ; 111(9): 1500-1508, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33487022

RESUMO

Using the correct name for phytopathogenic fungi and oomycetes is essential for communicating knowledge about species and their biology, control, and quarantine as well as for trade and research purposes. However, many plant pathogenic fungi are pleomorphic, meaning they produce different asexual (anamorph) and sexual (teleomorph) morphs in their life cycles. Therefore, more than one name has been applied to different morphs of the same species, which has confused users. The onset of DNA technologies makes it possible to connect different morphs of the same species, resulting in a move to a more natural classification system for fungi in which a single name for a genus and species can now be used. This move to a single nomenclature, coupled with the advent of molecular systematics and the introduction of polythetic taxonomic approaches, has been the main driving force for a reclassification of fungi, including pathogens. Nonetheless, finding the correct name for species remains challenging. In this article we outline a series of steps or considerations to greatly simplify this process and provide links to various online databases and resources to aid in determining the correct name. Additionally, a list of accurate names is provided for the most common genera and species of phytopathogenic fungi.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Assuntos
Fungos , Doenças das Plantas
16.
IMA Fungus ; 11(1): 25, 2020 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33292779

RESUMO

It is common practice in scientific journals to print genus and species names in italics. This is not only historical as species names were traditionally derived from Greek or Latin. Importantly, it also facilitates the rapid recognition of genus and species names when skimming through manuscripts. However, names above the genus level are not always italicized, except in some journals which have adopted this practice for all scientific names. Since scientific names treated under the various Codes of nomenclature are without exception treated as Latin, there is no reason why names above genus level should be handled differently, particularly as higher taxon names are becoming increasingly relevant in systematic and evolutionary studies and their italicization would aid the unambiguous recognition of formal scientific names distinguishing them from colloquial names. Several leading mycological and botanical journals have already adopted italics for names of all taxa regardless of rank over recent decades, as is the practice in the International Code of Nomenclature for algae, fungi, and plants, and we hereby recommend that this practice be taken up broadly in scientific journals and textbooks.

17.
Nat Commun ; 11(1): 5125, 2020 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-33046698

RESUMO

Mycorrhizal fungi are mutualists that play crucial roles in nutrient acquisition in terrestrial ecosystems. Mycorrhizal symbioses arose repeatedly across multiple lineages of Mucoromycotina, Ascomycota, and Basidiomycota. Considerable variation exists in the capacity of mycorrhizal fungi to acquire carbon from soil organic matter. Here, we present a combined analysis of 135 fungal genomes from 73 saprotrophic, endophytic and pathogenic species, and 62 mycorrhizal species, including 29 new mycorrhizal genomes. This study samples ecologically dominant fungal guilds for which there were previously no symbiotic genomes available, including ectomycorrhizal Russulales, Thelephorales and Cantharellales. Our analyses show that transitions from saprotrophy to symbiosis involve (1) widespread losses of degrading enzymes acting on lignin and cellulose, (2) co-option of genes present in saprotrophic ancestors to fulfill new symbiotic functions, (3) diversification of novel, lineage-specific symbiosis-induced genes, (4) proliferation of transposable elements and (5) divergent genetic innovations underlying the convergent origins of the ectomycorrhizal guild.


Assuntos
Fungos/genética , Genoma Fúngico , Micorrizas/genética , Simbiose , Ecossistema , Evolução Molecular , Proteínas Fúngicas/genética , Fungos/classificação , Fungos/fisiologia , Micorrizas/classificação , Micorrizas/fisiologia , Filogenia , Fenômenos Fisiológicos Vegetais , Plantas/microbiologia
18.
Fungal Genet Biol ; 144: 103444, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32822858

RESUMO

Currently, eight Phyllosticta species are known to be associated with several Citrus hosts, incorporating diverse lifestyles: while some of them are endophytic (P. capitalensis and P. citribraziliensis), others are pathogenic (P. citriasiana, P. citricarpa, P. citrichinaensis and P. paracitricarpa). Sexual reproduction plays a key role in the interaction between these Phyllosticta species and their Citrus hosts, especially for the spread and persistence of the pathogenic species in the environment. Given this, differences in sexual reproduction strategies could be related to the differences in lifestyles. To evaluate this hypothesis, we characterized the mating-type loci of six Citrus-associated Phyllosticta species from whole genome assemblies. Mating-type genes in the Citrus-associated Phyllosticta species are highly variable in their sequence content, but the genomic locations and organization of the mating-type loci are conserved. Phyllosticta citriasiana, P. citribraziliensis, P. citricarpa and P. paracitricarpa are heterothallic, while P. capitalensis and P. citrichinaensis are homothallic. In addition, the P. citrichinaensis MAT1-2 idiomorph occurs in a separate location from the mating-type locus. Ancestral state reconstruction suggests that homothallism is the ancestral thallism state in Phyllosticta, with a shift to heterothallism in Phyllosticta species that are pathogenic to Citrus. Moreover, the homothallic strategies of P. capitalensis and P. citrichinaensis result from independent evolutionary events, as P. capitalensis locus likely represents the ancestral state, and P. citrichinaensis homothallism has risen through a reversion in a heterothallic ancestor and underwent remodelling events. As the pathogenic species P. citriasiana, P. citricarpa and P. paracitricarpa are heterothallic and incapable of selfing, disease management practices focused in preventing the occurrence of sexual reproduction could assist in the control of Citrus Black Spot and Citrus Tan Spot diseases. This study emphasizes the importance of studying Citrus-Phyllosticta interactions under evolutionary and genomic perspectives, as these approaches can provide valuable information about the association between Phyllosticta species and their hosts, and also serve as guidance for the improvement of disease management practices.


Assuntos
Citrus/microbiologia , Genes Fúngicos Tipo Acasalamento/genética , Doenças das Plantas/genética , Reprodução/genética , Ascomicetos/genética , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/patogenicidade , Citrus/genética , Citrus/crescimento & desenvolvimento , Doenças das Plantas/microbiologia
19.
IMA Fungus ; 11: 14, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32714773

RESUMO

True fungi (Fungi) and fungus-like organisms (e.g. Mycetozoa, Oomycota) constitute the second largest group of organisms based on global richness estimates, with around 3 million predicted species. Compared to plants and animals, fungi have simple body plans with often morphologically and ecologically obscure structures. This poses challenges for accurate and precise identifications. Here we provide a conceptual framework for the identification of fungi, encouraging the approach of integrative (polyphasic) taxonomy for species delimitation, i.e. the combination of genealogy (phylogeny), phenotype (including autecology), and reproductive biology (when feasible). This allows objective evaluation of diagnostic characters, either phenotypic or molecular or both. Verification of identifications is crucial but often neglected. Because of clade-specific evolutionary histories, there is currently no single tool for the identification of fungi, although DNA barcoding using the internal transcribed spacer (ITS) remains a first diagnosis, particularly in metabarcoding studies. Secondary DNA barcodes are increasingly implemented for groups where ITS does not provide sufficient precision. Issues of pairwise sequence similarity-based identifications and OTU clustering are discussed, and multiple sequence alignment-based phylogenetic approaches with subsequent verification are recommended as more accurate alternatives. In metabarcoding approaches, the trade-off between speed and accuracy and precision of molecular identifications must be carefully considered. Intragenomic variation of the ITS and other barcoding markers should be properly documented, as phylotype diversity is not necessarily a proxy of species richness. Important strategies to improve molecular identification of fungi are: (1) broadly document intraspecific and intragenomic variation of barcoding markers; (2) substantially expand sequence repositories, focusing on undersampled clades and missing taxa; (3) improve curation of sequence labels in primary repositories and substantially increase the number of sequences based on verified material; (4) link sequence data to digital information of voucher specimens including imagery. In parallel, technological improvements to genome sequencing offer promising alternatives to DNA barcoding in the future. Despite the prevalence of DNA-based fungal taxonomy, phenotype-based approaches remain an important strategy to catalog the global diversity of fungi and establish initial species hypotheses.

20.
MycoKeys ; 67: 95-124, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32565683

RESUMO

Mycological investigation of various foods (mainly cowpea, groundnut, maize, rice, sorghum) and agricultural soils from two states in north-central Nigeria (Nasarawa and Niger), was conducted in order to understand the role of filamentous fungi in food contamination and public health. A total of 839 fungal isolates were recovered from 84% of the 250 food and all 30 soil samples. Preliminary identifications were made, based on macro- and micromorphological characters. Representative strains (n = 121) were studied in detail using morphology and DNA sequencing, involving genera/species-specific markers, while extrolite profiles using LC-MS/MS were obtained for a selection of strains. The representative strains grouped in seven genera (Aspergillus, Fusarium, Macrophomina, Meyerozyma, Neocosmospora, Neotestudina and Phoma). Amongst the 21 species that were isolated during this study was one novel species belonging to the Fusarium fujikuroi species complex, F. madaense sp. nov., obtained from groundnut and sorghum in Nasarawa state. The examined strains produced diverse extrolites, including several uncommon compounds: averantinmethylether in A. aflatoxiformans; aspergillimide in A. flavus; heptelidic acid in A. austwickii; desoxypaxillin, kotanin A and paspalitrems (A and B) in A. aflatoxiformans, A. austwickii and A. cerealis; aurasperon C, dimethylsulochrin, fellutanine A, methylorsellinic acid, nigragillin and pyrophen in A. brunneoviolaceus; cyclosporins (A, B, C and H) in A. niger; methylorsellinic acid, pyrophen and secalonic acid in A. piperis; aspulvinone E, fonsecin, kojic acid, kotanin A, malformin C, pyranonigrin and pyrophen in A. vadensis; and all compounds in F. madaense sp. nov., Meyerozyma, Neocosmospora and Neotestudina. This study provides snapshot data for prediction of food contamination and fungal biodiversity exploitation.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...