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1.
Fungal Genet Biol ; 156: 103613, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34332072

RESUMEN

Fusarium verticillioides is one of the most important fungal pathogens of maize since it causes severe yield losses and produces the mycotoxins fumonisins that represent a major concern for human and animal health. Information about genetic diversity and population structure of fungal pathogens is essential for developing disease management strategies. The aim of this research was to investigate the genetic structure of F. verticillioides isolated from different provinces of Iran through determination of mating type idiomorphs, phylogenetic analyses based on translation elongation factor-1 alpha (EF-1α), RNA Polymerase II Subunit (RPB2), beta-tubulin (tub2) and Calmodulin (cmdA) genes and genetic diversity analyses based on 6 simple-sequence repeats (SSRs). Both mating types were detected in Iranian populations of F. verticillioides, particularly in Qazvin and Khuzestan, with equal frequency, which highlighted that sexual reproduction is favorable under field conditions. However, the linkage disequilibrium indices did not support the hypothesis of random mating in Khuzestan and Fars. Although assessment of nucleotide diversity based on housekeeping genes showed low level of variation among strains, genotype diversity based on SSRs revealed a high level of genetic diversity within Iranian populations. AMOVA analysis highlighted that the genetic variation of F. verticillioides in Iran was mainly distributed within population of a single area (97%), while a small proportion of genetic variation (3%) resided among populations. These patterns of variation are likely explained by the continuous gene flow among populations isolated from different areas. On the other hand, principal coordinate analysis indicated that the distribution of genetic variation among populations could be explained by the geographical distances. Consequently, to reduce pathogen gene flow among regions, the quarantine processes in Iran should be intensified.


Asunto(s)
Repeticiones de Microsatélite , Zea mays , Fusarium , Humanos , Irán , Filogenia
2.
Int J Food Microbiol ; 330: 108667, 2020 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-32531666

RESUMEN

Fusarium fujikuroi species complex (FFSC) species are commonly encountered infecting rice, but knowledge of the diversity and toxigenic potential of the species is lacking in Brazil, the largest rice-producing country outside Asia. One hundred FFSC isolates obtained from national rice were identified using morphology and phylogeny of TEF, CAL and TUB genes. Eight previously known and one novel Fusarium species were identified. Three species accounted for around 60% of the strains: F. fujikuroi (n = 23), F. proliferatum (n = 22) and F. verticillioides (n = 16). The less frequent species were F. volatile (n = 8), F. anthophilum (n = 6), F. pseudocircinatum (n = 4), F. sterilihyphosum (n = 2) and F. begoniae (n = 1). The novel Fusarium species was represented by 18 isolates. All species produced at least one of the analyzed mycotoxins [beauvericin (BEA), fumonisins (FBs), moniliformin (MON) and enniatins (ENNs)]. BEA was produced by all species but F. verticillioides. The FBs (mainly FB1) were produced mostly by F. fujikuroi, F. proliferatum and F. verticillioides. F. begoniae and F. verticillioides did not produce ENNs and F. sterilihyphosum and F. begoniae did not produce MON, while the other species produced MON and ENNs. Our results add new knowledge of the diversity, geographical distribution and host range of FFSC species.


Asunto(s)
Fusarium/química , Fusarium/clasificación , Oryza/microbiología , Biodiversidad , Brasil , Fusarium/genética , Fusarium/aislamiento & purificación , Especificidad del Huésped , Micotoxinas/análisis , Filogenia , Venenos/análisis
3.
Toxins (Basel) ; 12(2)2020 02 14.
Artículo en Inglés | MEDLINE | ID: mdl-32075204

RESUMEN

Knowledge of the genetic diversity detected among fungal species belonging to the genus Aspergillus is of key importance for explaining their important ecological role in the environment and agriculture. The current study aimed to identify Aspergillus species occurring in the rhizosphere of sugarcane in the South of Iran, and to investigate their mycotoxin profiles. One-hundred and twenty-five Aspergillus strains were isolated from the soil of eight major sugarcane-producing sites, and were molecularly identified using sequences of partial -tubulin (benA) and partial calmodulin (CaM) genes. Our molecular and phylogenetic results showed that around 70% of strains belonged to the Aspergillus section Nigri, and around 25% of species belonged to the Aspergillus section Terrei. Species belonging to both sections are able to produce different mycotoxins. The production of mycotoxins was measured for each species, according to their known mycotoxin profile: patulin (PAT) and sterigmatocystin (STG) for Aspergillusterreus; ochratoxin A (OTA) and fumonisins for Aspergilluswelwitschiae; and OTA alone for Aspergillustubingensis. The data showed that the production of OTA was detected in only 4 out of 10 strains of A.welwitschiae, while none of the A.tubingensis strains analyzed produced the mycotoxin. Fumonisins were produced by 8 out of 10 strains of A.welwitschiae. Finally, none of the 23 strains of A.terreus produced STG, while 13 of them produced PAT. The occurrence of such mycotoxigenic plant pathogens among the fungal community occurring in soil of sugarcane fields may represent a significant source of inoculum for the possible colonization of sugarcane plants, since the early stages of plant growth, due to the mycotoxin production capability, could have worrisome implications in terms of both the safety and loss of products at harvest.


Asunto(s)
Aspergillus/aislamiento & purificación , Micotoxinas/biosíntesis , Rizosfera , Saccharum/microbiología , Aspergillus/genética , Aspergillus/metabolismo , Irán , Filogenia , Saccharum/crecimiento & desarrollo , Microbiología del Suelo
4.
Int J Food Microbiol ; 319: 108491, 2020 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-31935649

RESUMEN

Accurate identification of fungi occurring on agrofood products is the key aspect of any prevention and pest management program, offering valuable information in leading crop health and food safety. Fungal species misidentification can dramatically impact biodiversity assessment, ecological studies, management decisions, and, concerning toxigenic fungi, health risk assessment, since they can produce a wide range of toxic secondary metabolites, referred to as mycotoxins. Since each toxigenic fungal species can have its own mycotoxin profile, a correct species identification, hereby attempted with universal DNA barcoding approach, could have a key role in mycotoxins prevention strategies. Currently, identification of single marker for species resolution in fungi has not been achieved and the analysis of multiple genes is used, with the advantage of an accurate species identification and disadvantage of difficult setting up of PCR-based diagnostic assays. In the present paper, we describe our strategy to set up a DNA-based species identification of fungal species associated with maize ear rot, combining DNA barcoding approach and species-specific primers design for PCR based assays. We have (i) investigated the appropriate molecular marker for species identification, limited to mycobiota possibly occurring on maize, identifying calmodulin gene as single taxonomically informative entity; (ii) designed 17 sets of primers for rapid identification of 14 Fusarium, 10 Aspergillus, 2 Penicillium, and 2 Talaromyces species or species groups, and finally (iii) tested specificity of the 17 set of primers, in combination with 3 additional sets previously developed.


Asunto(s)
Calmodulina/genética , Hongos/clasificación , Hongos/genética , Micotoxinas/análisis , Zea mays/microbiología , Aspergillus/clasificación , Aspergillus/genética , Aspergillus/metabolismo , Biodiversidad , Contaminación de Alimentos/análisis , Inocuidad de los Alimentos , Fusarium/clasificación , Fusarium/genética , Fusarium/metabolismo , Penicillium/clasificación , Penicillium/genética , Penicillium/metabolismo , Enfermedades de las Plantas/microbiología , Reacción en Cadena de la Polimerasa , Talaromyces/clasificación , Talaromyces/genética , Talaromyces/metabolismo
5.
Int J Food Microbiol ; 234: 24-35, 2016 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-27376677

RESUMEN

DNA-based phylogenetic analyses have resolved the fungal genus Fusarium into multiple species complexes. The F. incarnatum-equiseti species complex (FIESC) includes fusaria associated with several diseases of agriculturally important crops, including cereals. Although members of FIESC are considered to be only moderately aggressive, they are able to produce a diversity of mycotoxins, including trichothecenes, which can accumulate to harmful levels in cereals. High levels of cryptic speciation have been detected within the FIESC. As a result, it is often necessary to use approaches other than morphological characterization to distinguish species. In the current study, we used a polyphasic approach to characterize a collection of 69 FIESC isolates recovered from cereals in Europe, Turkey, and North America. In a species phylogeny inferred from nucleotide sequences from four housekeeping genes, 65 of the isolates were resolved within the Equiseti clade of the FIESC, and four isolates were resolved within the Incarnatum clade. Seven isolates were resolved as a genealogically exclusive lineage, designated here as FIESC 31. Phylogenies based on nucleotide sequences of trichothecene biosynthetic genes and MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry) were largely concordant with phylogeny inferred from the housekeeping gene. Finally, Liquid Chromatography (Time-Of-Flight) Mass Spectrometry [LC-(TOF-)MS(/MS)] revealed variability in mycotoxin production profiles among the different phylogenetic species investigated in this study.


Asunto(s)
Grano Comestible/microbiología , Fusarium/clasificación , Fusarium/genética , Genes Esenciales/genética , Micotoxinas/biosíntesis , Tricotecenos/biosíntesis , Secuencia de Bases , Europa (Continente) , Fusarium/aislamiento & purificación , Fusarium/metabolismo , Micotoxinas/genética , América del Norte , Filogenia , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Tricotecenos/genética , Turquía
6.
Fungal Genet Biol ; 73: 39-52, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25281783

RESUMEN

The ability to produce fumonisin mycotoxins varies among members of the black aspergilli. Previously, analyses of selected genes in the fumonisin biosynthetic gene (fum) cluster in black aspergilli from California grapes indicated that fumonisin-nonproducing isolates of Aspergillus welwitschiae lack six fum genes, but nonproducing isolates of Aspergillus niger do not. In the current study, analyses of black aspergilli from grapes from the Mediterranean Basin indicate that the genomic context of the fum cluster is the same in isolates of A. niger and A. welwitschiae regardless of fumonisin-production ability and that full-length clusters occur in producing isolates of both species and nonproducing isolates of A. niger. In contrast, the cluster has undergone an eight-gene deletion in fumonisin-nonproducing isolates of A. welwitschiae. Phylogenetic analyses suggest each species consists of a mixed population of fumonisin-producing and nonproducing individuals, and that existence of both production phenotypes may provide a selective advantage to these species. Differences in gene content of fum cluster homologues and phylogenetic relationships of fum genes suggest that the mutation(s) responsible for the nonproduction phenotype differs, and therefore arose independently, in the two species. Partial fum cluster homologues were also identified in genome sequences of four other black Aspergillus species. Gene content of these partial clusters and phylogenetic relationships of fum sequences indicate that non-random partial deletion of the cluster has occurred multiple times among the species. This in turn suggests that an intact cluster and fumonisin production were once more widespread among black aspergilli.


Asunto(s)
Aspergillus niger/genética , Fumonisinas/metabolismo , Genoma Fúngico , Aspergillus niger/metabolismo , Familia de Multigenes , Filogenia , Vitis/microbiología
7.
Int J Food Microbiol ; 188: 75-82, 2014 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-25087207

RESUMEN

Fumonisin contamination of maize is considered a serious problem in most maize-growing regions of the world, due to the widespread occurrence of these mycotoxins and their association with toxicosis in livestock and humans. Fumonisins are produced primarily by species of Fusarium that are common in maize grain, but also by some species of Aspergillus sect. Nigri, which can also occur on maize kernels as opportunistic pathogens. Understanding the origin of fumonisin contamination in maize is a key component in developing effective management strategies. Although some fungi in Aspergillus sect. Nigri are known to produce fumonisins, little is known about the species which are common in maize and whether they make a measurable contribution to fumonisin contamination of maize grain. In this work, we evaluated populations of Aspergillus sect. Nigri isolated from maize in USA and Italy, focusing on analysis of housekeeping genes, the fum8 gene and in vitro capability of producing fumonisins. DNA sequencing was used to identify Aspergillus strains belonging to sect. Nigri, in order to compare species composition between the two populations, which might influence specific mycotoxicological risks. Combined beta-tubulin/calmodulin sequences were used to genetically characterize 300 strains (199 from Italy and 101 from USA) which grouped into 4 clades: Aspergillus welwitschiae (syn. Aspergillus awamori, 14.7%), Aspergillus tubingensis (37.0%) and Aspergillus niger group 1 (6.7%) and group 2 (41.3%). Only one strain was identified as Aspergillus carbonarius. Species composition differed between the two populations; A. niger predominated among the USA isolates (69%), but comprised a smaller percentage (38%) of Italian isolates. Conversely, A. tubingensis and A. welwitschiae occurred at higher frequencies in the Italian population (42% and 20%, respectively) than in the USA population (27% and 5%). The evaluation of FB2 production on CY20S agar revealed 118 FB2 producing and 84 non-producing strains distributed among the clades: A. welwitschiae, A. niger group 1 and A. niger group 2, confirming the potential of Aspergillus sect. Nigri species to contribute to total fumonisin contamination of maize. A higher percentage of A. niger isolates (72.0%) produced FB2 compared to A. welwitschiae (36.6%). The percentage of FB2-producing A. niger strains was similar in the USA and Italian populations; however, the predominance of A. niger in the USA population suggests a higher potential for fumonisin production. Some strains with fum8 present in the genome did not produce FB2in vitro, confirming the ineffectiveness of fum8 presence as a predictor of FB2 production.


Asunto(s)
Aspergillus/fisiología , Fumonisinas/análisis , Micotoxinas/biosíntesis , Micotoxinas/genética , Zea mays/microbiología , Aspergillus/clasificación , Aspergillus/genética , Aspergillus/aislamiento & purificación , Aspergillus/metabolismo , Biodiversidad , Humanos , Italia , Filogenia , Estados Unidos
8.
Food Microbiol ; 41: 52-9, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24750813

RESUMEN

Aflatoxins are highly toxic carcinogens that contaminate crops worldwide. Previous studies conducted in Nigeria and Ghana found high concentrations of aflatoxins in pre- and post-harvest maize. However, little information is available on the population structure of Aspergillus Sect. Flavi in West Africa. We determined the incidence of Aspergillus Sect. Flavi and the level of aflatoxin contamination in 91 maize samples from farms and markets in Nigeria and Ghana. Aspergillus spp. were recovered from 61/91 maize samples and aflatoxins B1 and/or B2 occurred in 36/91 samples. Three samples from the farms also contained aflatoxin G1 and/or G2. Farm samples were more highly contaminated than were samples from the market, in terms of both the percentage of the samples contaminated and the level of mycotoxin contamination. One-hundred-and-thirty-five strains representative of the 1163 strains collected were identified by using a multilocus sequence analysis of portions of the genes encoding calmodulin, ß-tubulin and actin, and evaluated for aflatoxin production. Of the 135 strains, there were 110 - Aspergillus flavus, 20 - Aspergillus tamarii, 2 - Aspergillus wentii, 2 - Aspergillus flavofurcatus, and 1 - Aspergillus parvisclerotigenus. Twenty-five of the A. flavus strains and the A. parvisclerotigenus strain were the only strains that produced aflatoxins. The higher contamination of the farm than the market samples suggests that the aflatoxin exposure of rural farmers is even higher than previously estimated based on reported contamination of market samples. The relative infrequency of the A. flavus SBG strains, producing small sclerotia and high levels of both aflatoxins (B and G), suggests that long-term chronic exposure to this mycotoxin are a much higher health risk in West Africa than is the acute toxicity due to very highly contaminated maize in east Africa.


Asunto(s)
Aflatoxinas/análisis , Aspergillus/aislamiento & purificación , Aspergillus/metabolismo , Contaminación de Alimentos/análisis , Zea mays/química , Zea mays/microbiología , Aflatoxinas/metabolismo , Aspergillus/clasificación , Aspergillus/genética , Ghana , Datos de Secuencia Molecular , Nigeria , Filogenia
9.
Plant Dis ; 98(3): 344-350, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30708436

RESUMEN

Management of Calonectria spp. infections in nurseries requires scheduled fungicide applications, particularly with methyl benzimidazole carbamates (MBCs) and sterol demethylation inhibitors (DMIs). Due to rising concerns about the occurrence of MBC resistance in different Calonectria populations and variability in prochloraz efficacy in controlling these pathogens, a detailed study on prochloraz sensitivity distributions of Calonectria isolates belonging to the Calonectria scoparia complex was carried out. In total, 105 isolates collected in two distinct periods (1993 to 1996 and 2005 to 2009) were analyzed for prochloraz sensitivity. Based on DNA sequencing and phylogenetic analyses of ß-tubulin, histone H3, and translation elongation factor-1α gene sequences, 69 and 36 isolates were identified as C. pauciramosa and C. polizzii, respectively. The isolates collected more recently (group B) had a reduced prochloraz sensitivity, as indicated by greater values for the effective dose to reduce growth by 50% than those collected earlier (group A). The reduced sensitivity detected in vitro corresponded to partial loss of fungicide efficacy in controlling infections in red clover and feijoa under controlled and semi-field conditions, respectively. Frequent prochloraz application in nurseries for controlling Calonectria spp. infections is discouraged.

10.
Mol Microbiol ; 90(2): 290-306, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23937442

RESUMEN

Fumonisins are a family of carcinogenic secondary metabolites produced by members of the Fusarium fujikuroi species complex (FFSC) and rare strains of Fusarium oxysporum. In Fusarium, fumonisin biosynthetic genes (FUM) are clustered, and the cluster is uniform in gene organization. Here, sequence analyses indicated that the cluster exists in five different genomic contexts, defining five cluster types. In FUM gene genealogies, evolutionary relationships between fusaria with different cluster types were largely incongruent with species relationships inferred from primary-metabolism (PM) gene genealogies, and FUM cluster types are not trans-specific. In addition, synonymous site divergence analyses indicated that three FUM cluster types predate diversification of FFSC. The data are not consistent with balancing selection or interspecific hybridization, but they are consistent with two competing hypotheses: (i) multiple horizontal transfers of the cluster from unknown donors to FFSC recipients and (ii) cluster duplication and loss (birth and death). Furthermore, low levels of FUM gene divergence in F. bulbicola, an FFSC species, and F. oxysporum provide evidence for horizontal transfer of the cluster from the former, or a closely related species, to the latter. Thus, uniform gene organization within the FUM cluster belies a complex evolutionary history that has not always paralleled the evolution of Fusarium.


Asunto(s)
Evolución Molecular , Fumonisinas/metabolismo , Fusarium/genética , Transferencia de Gen Horizontal , Genes Fúngicos , Secuencia de Aminoácidos , Fumonisinas/química , Fusarium/clasificación , Fusarium/metabolismo , Duplicación de Gen , Regulación Fúngica de la Expresión Génica , Familia de Multigenes , Filogenia
11.
Int J Food Microbiol ; 165(2): 163-8, 2013 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-23732831

RESUMEN

Dried vine fruits may be heavily colonized by Aspergillus species. The molecular biodiversity of an Aspergillus population (234 strains) isolated from dried vine fruit samples of worldwide origin were analyzed by investigating four housekeeping gene loci (calmodulin, ß-tubulin, elongation factor 1-α, RPB2). Aspergillus Sect. Nigri was dominant and the strains were identified as A. tubingensis (138), A. awamori (38), A. carbonarius (27), A. uvarum (16) and A. niger (11). Four Aspergillus flavus strains were also identified from Chilean raisins. Two clusters closely related to the A. tubingensis species with a significant bootstrap (60% and 99%) were identified as distinct populations. Among the four loci, RPB2 showed the highest genetic variability. This is the first complete study on the worldwide distribution of black Aspergilli occurring on dried vine fruits identified by a molecular approach.


Asunto(s)
Aspergillus/genética , Microbiología de Alimentos , Frutas/microbiología , Aspergillus/aislamiento & purificación , Biodiversidad , Genes Fúngicos/genética , Tipificación de Secuencias Multilocus , Filogenia
12.
IMA Fungus ; 3(2): 159-73, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23355969

RESUMEN

Aspergillus floridensis and A. trinidadensis spp. nov. are described as novel uniseriate species of Aspergillus section Nigri isolated from air samples. To describe the species we used phenotypes from 7-d Czapek yeast extract agar culture (CYA), creatine agar culture (CREA) and malt extract agar culture (MEA), with support by molecular analysis of the ß-tubulin, calmodulin, RNA polymerase II (RPB2), and translation elongation factor-alpha (TEF) gene amplified and sequenced from 56 air isolates and one isolate from almonds belonging to Aspergillus sectionNigri.Aspergillus floridensis is closely related to A. aculeatus, and A. trinidadensis is closely related to A. aculeatinus. Aspergillus brunneoviolaceus (syn. A. fijiensis) and A. uvarum are reported for the first time from the USA and from the indoor air environment. The newly described species do not produce ochratoxin A.

13.
Fungal Biol ; 115(11): 1138-50, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22036292

RESUMEN

Aspergillus section Nigri is an important group of species for food and medical mycology, and biotechnology. The Aspergillus niger 'aggregate' represents its most complicated taxonomic subgroup containing eight morphologically indistinguishable taxa: A. niger, Aspergillus tubingensis, Aspergillus acidus, Aspergillus brasiliensis, Aspergillus costaricaensis, Aspergillus lacticoffeatus, Aspergillus piperis, and Aspergillus vadensis. Aspergillus awamori, first described by Nakazawa, has been compared taxonomically with other black aspergilli and recently it has been treated as a synonym of A. niger. Phylogenetic analyses of sequences generated from portions of three genes coding for the proteins ß-tubulin (benA), calmodulin (CaM), and the translation elongation factor-1 alpha (TEF-1α) of a population of A. niger strains isolated from grapes in Europe revealed the presence of a cryptic phylogenetic species within this population, A. awamori. Morphological, physiological, ecological and chemical data overlap occurred between A. niger and the cryptic A. awamori, however the splitting of these two species was also supported by AFLP analysis of the full genome. Isolates in both phylospecies can produce the mycotoxins ochratoxin A and fumonisin B2, and they also share the production of pyranonigrin A, tensidol B, funalenone, malformins, and naphtho-γ-pyrones. In addition, sequence analysis of four putative A. awamori strains from Japan, used in the koji industrial fermentation, revealed that none of these strains belong to the A. awamori phylospecies.


Asunto(s)
Aspergillus niger/clasificación , Aspergillus/clasificación , Filogenia , Análisis del Polimorfismo de Longitud de Fragmentos Amplificados , Aspergillus/genética , Aspergillus/aislamiento & purificación , Aspergillus/metabolismo , Aspergillus niger/genética , Aspergillus niger/aislamiento & purificación , Aspergillus niger/metabolismo , Proteínas Fúngicas/genética , Datos de Secuencia Molecular , Micotoxinas/metabolismo , Microbiología del Suelo , Tubulina (Proteína)/genética , Vitis/microbiología
14.
Toxins (Basel) ; 3(10): 1294-309, 2011 10.
Artículo en Inglés | MEDLINE | ID: mdl-22069697

RESUMEN

The Fusarium graminearum species complex (FGSC) is a group of mycotoxigenic fungi that are the primary cause of Fusarium head blight (FHB) of wheat worldwide. The distribution, frequency of occurrence, and genetic diversity of FGSC species in cereal crops in South America is not well understood compared to some regions of Asia, Europe and North America. Therefore, we examined the frequency and genetic diversity of a collection of 183 FGSC isolates recovered from wheat grown during multiple growing seasons and across a large area of eastern Argentina, a major wheat producing region in South America. Sequence analysis of the translation elongation factor 1-α and ß-tubulin genes as well as Amplified Fragment Length Polymorphism (AFLP) analyses indicated that all isolates were the FGSC species F. graminearum sensu stricto. AFLP analysis resolved at least 11 subgroups, and all the isolates represented different AFLP haplotypes. AFLP profile and geographic origin were not correlated. Previously obtained trichothecene production profiles of the isolates revealed that the 15-acetyldeoxynivalenol chemotype was slightly more frequent than the 3-acetyldeoxynivalenol chemotype among the isolates. These data extend the current understanding of FGSC diversity and provide further evidence that F. graminearum sensu stricto is the predominant cause of FHB in the temperate main wheat-growing area of Argentina. Moreover, two isolates of F. crookwellense and four of F. pseudograminearum were also recovered from wheat samples and sequenced. The results also suggest that, although F. graminearum sensu stricto was the only FGSC species recovered in this study, the high level of genetic diversity within this species should be considered in plant breeding efforts and development of other disease management strategies aimed at reducing FHB.


Asunto(s)
Fusarium/genética , Triticum/microbiología , Análisis del Polimorfismo de Longitud de Fragmentos Amplificados , Argentina , ADN de Hongos/genética , Genes Fúngicos/genética , Variación Genética , Datos de Secuencia Molecular , Factor 1 de Elongación Peptídica/genética , Filogenia , Análisis de Secuencia de ADN , Tubulina (Proteína)/genética
15.
Int J Food Microbiol ; 145(2-3): 437-43, 2011 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-21296447

RESUMEN

An extensive use of Weissella (W.) confusa is currently being made for the production of a variety of fermented foods and beverages although some strains of this species have emerged as opportunistic pathogens for humans and animals. Nevertheless, no rapid methods are available for the reliable identification of W. confusa. We developed a novel PCR using AFLP (Amplified Fragment Length Polymorphism)-derived primers for the rapid and unequivocal identification of W. confusa. Fluorescent AFLP of 30 strains of W. confusa, Leuconostoc citreum, Lactobacillus (Lb.) brevis, Lb. rossiae, Lb. plantarum and Lb. buchneri allowed us to detect, purify and sequence several W. confusa specific AFLP fragments. The homology search in BLAST of a 303 bp nucleotide sequence revealed a ≤ 77% identity of the purified fragment with the lepA gene of several lactic acid bacteria. A PCR assay targeting 225 bp of this fragment was developed and tested against the DNA of 109 strains, including 34 foodborne and clinical W. confusa and 75 strains of 47 phylogenetically closely and distantly related species, resulting in 100% specificity with a detection limit of 16 pg. Being the first species-specific PCR to date developed for the rapid and unambiguous identification of W. confusa, this novel assay could be a reliable and efficient tool for detecting W. confusa not only in food and beverages, but also in clinical specimens, thus contributing to clarify its real significance in human and animal infections.


Asunto(s)
Análisis del Polimorfismo de Longitud de Fragmentos Amplificados , Reacción en Cadena de la Polimerasa/métodos , Weissella/genética , Proteínas Bacterianas/genética , Cartilla de ADN/genética , ADN Bacteriano/genética , Lactobacillus/genética , Leuconostoc/genética , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico , Especificidad de la Especie , Weissella/clasificación
16.
J Agric Food Chem ; 58(16): 9266-72, 2010 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-20666454

RESUMEN

Aspergillus niger is a significant component of the fungal community on grapes. The mycotoxin fumonisin B2 (FB2) was recently detected in grape must and wine as well as in cultures of some A. niger strains isolated from grapes and raisins. This study examined 48 strains of Aspergillus section Nigri for the presence of the fumonisin biosynthetic gene fum8 in relation to FB2 production. The fum8 gene was detected in only 11 A. niger strains, 9 of which also produced FB2. Maximum parsimony analysis based on the calmodulin gene sequence indicated that the presence/absence of fum8 is not correlated with the phylogenetic relationship of the isolates. This is the first report correlating the presence of a fumonisin biosynthetic gene with fumonisin production in A. niger from an important food crop. The results suggest that the absence of FB2 production in grape isolates of A. niger can result from the absence of at least one gene essential for production.


Asunto(s)
Aspergillus niger/genética , Fumonisinas/metabolismo , Genes Fúngicos , Micotoxinas/biosíntesis , Vitis/microbiología , Aspergillus niger/aislamiento & purificación , Secuencia de Bases , Southern Blotting , Cartilla de ADN
17.
Int J Syst Evol Microbiol ; 58(Pt 4): 1032-9, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18398215

RESUMEN

A novel species, Aspergillus uvarum sp. nov., is described within Aspergillus section Nigri. This species can be distinguished from other black aspergilli based on internal transcribed spacers (ITS), beta-tubulin and calmodulin gene sequences, by AFLP analysis and by extrolite profiles. Aspergillus uvarum sp. nov. isolates produced secalonic acid, common to other Aspergillus japonicus-related taxa, and geodin, erdin and dihydrogeodin, which are not produced by any other black aspergilli. None of the isolates were found to produce ochratoxin A. The novel species is most closely related to two atypical strains of Aspergillus aculeatus, CBS 114.80 and CBS 620.78, and was isolated from grape berries in Portugal, Italy, France, Israel, Greece and Spain. The type strain of Aspergillus uvarum sp. nov. is IMI 388523T=CBS 127591T=ITEM 4834T=IBT26606T.


Asunto(s)
Aspergillus/clasificación , Aspergillus/aislamiento & purificación , Microbiología de Alimentos , Vitis/microbiología , Aspergillus/genética , Aspergillus/metabolismo , Benzofuranos/metabolismo , Calmodulina/genética , ADN de Hongos/genética , ADN Intergénico/genética , Europa (Continente) , Proteínas Fúngicas/genética , Genes Fúngicos , Datos de Secuencia Molecular , Fenotipo , Filogenia , Especificidad de la Especie , Terminología como Asunto , Tubulina (Proteína)/genética , Xantonas/metabolismo
18.
Am J Respir Crit Care Med ; 172(6): 738-44, 2005 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-15947287

RESUMEN

The still-high mortality for lung cancer urgently requires the availability of new, noninvasive diagnostic tools for use in early diagnosis and screening programs. Recently, exhaled breath condensate (EBC) has been proposed as a useful tool to obtain biological information on lung cancer disease. This study provides, for the first time, evidence that DNA alterations already described in lung cancer are detectable in EBC from patients with non-small cell lung cancer (NSCLC) and in healthy subjects. Thirty patients with histologic evidence of NSCLC and 20 healthy subjects were enrolled in the present study. All subjects had allelotyping analysis of DNA from EBC (EBC-DNA) and from whole blood (WB-DNA) of a selected panel of five microsatellites (D3S2338, D3S1266, D3S1300, D3S1304, D3S1289) located in chromosomal region 3p. Results from healthy subjects and subjects with cancer, and from EBC and WB, were compared. In addition, the relationships with smoking habit and clinicopathologic tumor features were considered. Microsatellite alterations (MAs) were found in 53% of EBC-DNA and in 10% of WB-DNA loci investigated in patients with NSCLC (p < 10(-6)); conversely, MAs were present only in 13% of EBC-DNA and in 2% of WB-DNA informative loci in healthy subjects. In patients with NSCLC, a direct association between number of MAs detected in EBC-DNA and tobacco consumption was observed. We conclude that EBC-DNA is highly sensitive in detecting MA information unique to patients with lung cancer. Furthermore, MA information seems to be directly related with tobacco consumption, and is potentially applicable to screening and early diagnostic programs for patients with NSCLC.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/genética , Espiración/genética , Neoplasias Pulmonares/genética , Repeticiones de Microsatélite , Anciano , Carcinoma de Pulmón de Células no Pequeñas/patología , ADN de Neoplasias/sangre , ADN de Neoplasias/genética , Femenino , Humanos , Pérdida de Heterocigocidad , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Fumar/efectos adversos
19.
FEMS Microbiol Lett ; 230(2): 235-40, 2004 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-14757245

RESUMEN

Fusarium proliferatum and Fusarium oxysporum are the causal agents of a destructive disease of asparagus called Fusarium crown and root rot. F. proliferatum from asparagus produces fumonisin B1 and B2, which have been detected as natural contaminants in infected asparagus plants. Polymerase chain reaction (PCR) assays were developed for the rapid identification of F. proliferatum and F. oxysporum in asparagus plants. The primer pairs are based on calmodulin gene sequences. The PCR products from F. proliferatum and F. oxysporum were 526 and 534 bp long, respectively. The assays were successfully applied to identify both species from the vegetative part of the plants.


Asunto(s)
Asparagus/microbiología , Calmodulina/genética , Cartilla de ADN , Fusarium/aislamiento & purificación , Fusarium/patogenicidad , Reacción en Cadena de la Polimerasa/métodos , Secuencia de Bases , Datos de Secuencia Molecular , Enfermedades de las Plantas/microbiología , Especificidad de la Especie
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