Foreword: Special issue Mycotoxins in Latin America

Latin America with its considerable North-South extent is subject to climate that varies from tropical, subtropical and warm temperate to temperate. Different agricultural products are produced in the area including cereals, oilseeds, beans, fruits and nuts together with animal production including cattle for beef and milk, pigs, poultry and fish. The heterogeneity of agriculture in Latin America is reflected in the diversity of the region's farm structures. While agriculture in the Southern Cone is dominated by large, commercial and export-oriented farms, particularly in Argentina and Brazil, besides increasingly in other countries like Uruguay, much of the rest of the region is characterised by smallholder and family agriculture. The contamination of agricultural products with mycotoxins has impact both human and animal health, as well as the economy due to losses related to rejections of agricultural products and by-products during trade. The economic burden related to the consumption of mycotoxins by animals is especially important, causing productivity losses up to the death of animals. The relevant mycotoxins are fumonisins, deoxynivalenol (DON) and zearalenone (ZEN) in cereals and cereal-based products, aflatoxins in cereals, oily seeds and nuts, aflatoxin M1 in milk and dairy products as well as ochratoxin A (OTA) in coffee, grapes and raisins. Co-occurrence of mycotoxins has also been observed mainly with aflatoxins and fumonisins in different Latin American countries (Torres et al., 2015). Advances on legislation in different countries including Argentina, Brazil, Chile, Mexico and Uruguay have been done to establish maximum limits for mycotoxins including aflatoxins, DON, ZEN, OTA, patulin and ergot alkaloids (ANVISA, 2011/2017; CAA, 2019/2021, Norma Oficial Mexicana, N.-243-S., 2010/2010; Reglamento Sanitario de los Alimentos, 2013).Fil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; ArgentinaFil: Torres, Adriana Mabel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; ArgentinaFil: Torres, Olga. Laboratorio Diagnóstico Molecular; GuatemalaFil: Mallmann, Carlos Alberto. Universidade Federal de Santa Maria; Brasi

Natural occurrence of alternariol and alternariol monomethyl ether in soya beans

The natural occurrence of alternariol (AOH) and alternariol monomethyl ether (AME) in soya beans harvestedin Argentina was evaluated. Both toxins were simultaneously detected by using HPLC analysis coupled with a solid phase extraction column clean-up. Characteristics of this in-house method such as accuracy, precision and detection and quantification limits were defined by means of recovery test with spiked soya bean samples. Out of 50 soya bean samples, 60% showed contamination with the mycotoxins analyzed; among them, 16% were only contaminated with AOH and 14% just with AME. Fifteen of the positive samples showed co-occurrence of both mycotoxins analyzed. AOH was detected in concentrations ranging from 25 to 211 ng/g, whereas AME was found in concentrations ranging from 62 to 1,153 ng/g. Although a limited number of samples were evaluated, this is the first report on the natural occurrence of Alternaria toxins in soya beans and is relevant from the point of view of animal public health.Alternaria toxins in soya beans and is relevant from the point of view of animal public health.Fil: Oviedo, M. S.. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Barros, Germán Gustavo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Ramirez, M. L.. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentin

Effects of water activity and temperature on fusaric and fusarinolic acid production by Fusarium temperatum

Fusaric acid (FA) is a secondary metabolite produced by several Fusarium species that commonly is isolated from maize and maize-based foods and feeds, and is toxic to some plants and animals, most notably cotton. Fusarinolic acid (FnA) is closely related to FA and is enzymatically derived from it, but much less is known about its toxicity to humans and other animals. We determined the effects of water activity (aW – 0.95, 0.98 and 0.995), temperature (15°, 25° and 30 °C), incubation time (7, 14, 21 and 28 days) and their interactions on FA and FnA production by two strains of F. temperatum isolated from maize growing on sterile maize grain. The amount of FA and FnA accumulated was measured by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). Both compounds were accumulated by both strains of F. temperatum under all evaluated conditions. The amount of FnA produced always exceeded the amount of FA produced (max 50,000 ng/g and 4,500 ng/g, respectively). Temperature, aW, incubation time, and the two- and three-way interactions amongst them all significantly impacted FA and FnA accumulation. Factors favouring fungal growth and mycotoxin production include insect damage, high humidity, delays in harvest, and improper (wet) storage. Grain colonization by F. temperatum begins in the field, but fungal growth and mycotoxin production can easily continue in storage if conditions are right. Thus, from a toxicological point of view, F. temperatum represents a risk for maize under both field and storage conditions. Our data enable better risk estimates and strategies to reduce FA and FnA in the food and feed chains. The highest level of FA was detected at 0.995aW and was independent of temperature and length of incubation, suggesting that there is a limit to the amount of FA that can be accumulated by F. temperatum growing under laboratory conditions. Strikingly high amounts of FnA were observed under all incubation conditions, often exceeding FA levels by 20× to 200× . This result suggests that FnA is more important to the fungus than is FA, and that FA might be little more than an intermediate in a pathway to FnA. The role of the accumulated FnA is unknown, but its role as a toxin may have been discounted since studies to date report limited toxicity. However, if FnA is tested for toxicity at higher levels, such as those identified in this study, then it could have significant toxicological, or other effects that have not previously been considered.Fil: Fumero, María Verónica. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; ArgentinaFil: Sulyok, Michael. University of Natural Resources and Life Sciences. Center for Analytical Chemistry. Department of Agrobiotechnology; AustriaFil: Ramirez, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; ArgentinaFil: Leslie, John. Kansas State University. Throckmorton Plant Sciences Center. Department of Plant Pathology; Estados UnidosFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; Argentin

Toxigenic profile and AFLP variability of Alternaria alternata and Alternaria infectoria occurring on wheat

Abstract The objectives of this study were to evaluate the ability to produce alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) by A. alternata and A. infectoria strains recovered from wheat kernels obtained from one of the main production area in Argentina; to confirm using AFLPs molecular markers the identity of the isolates up to species level, and to evaluate the intra and inter-specific genetic diversity of these two Alternaria species. Among all the Alternaria strains tested (254), 84% of them were able to produce mycotoxins. The most frequent profile of toxin production found was the co-production of AOH and AME in both species tested. TA was only produced by strains of A. alternata. Amplified fragment polymorphism (AFLPs) analysis was applied to a set of 89 isolates of Alternaria spp (40 were A. infectoria and 49 were A. alternata) in order to confirm the morphological identification. The results showed that AFLPs are powerful diagnostic tool for differentiating between A. alternata and A. infectoria. Indeed, in the current study the outgroup strains, A. tenuissima was consistently classified. Characteristic polymorphic bands separated these two species regardless of the primer combination used. Related to intraspecific variability, A. alternata and A. infectoria isolates evaluated seemed to form and homogeneous group with a high degree of similarity among the isolates within each species. However, there was more scoreable polymorphism within A. alternata than within A. infectoria isolates. There was a concordance between morphological identification and separation up to species level using molecular markers. Clear polymorphism both within and between species showed that AFLP can be used to asses genetic variation in A. alternata and A. infectoria. The most important finding of the present study was the report on AOH and AME production by A. infectoria strains isolated from wheat kernels in Argentina on a semisynthetic media for the first time. Also, specific bands for A. alternata and A. infectoria have been identified; these may be useful for the design of specific PCR primers in order to differentiate these species and to detect them in cereals.Fil: Oviedo, Maria Silvina. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia. Cat.de Micología; Argentina;Fil: Sturm, María Elena. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia; Argentina;Fil: Reynoso, Maria Marta. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia; Argentina;Fil: Chulze, Sofia Noemi. Universidad Nacional de Cordoba. Facultad de Cs.quimicas. Departamento de Bioquimica Clinica. Cat.de Inmunologia; Argentina;Fil: Ramirez, Maria Laura. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia; Argentina

Preliminary study on the use of chitosan as an eco-friendly alternative to control fusarium growth and mycotoxin production on maize and wheat

The objectives of the present study were to determine the combined effects of chitosan and water activity (a W ) on growth and mycotoxin production in situ on the two most important Fusarium species (F. proliferatum and F. verticillioides) present on maize, and on F. graminearum, the main pathogen causing Fusarium head blight on wheat. Results showed that low-molecular-weight chitosan with more than 70% deacetylation at the lowest dose used (0.5 mg/g) was able to reduce deoxynivalenol (DON) and fumonisin (FBs) production on irradiated maize and wheat grains. Growth rates of F. graminearum also decreased at the lowest chitosan dose used (0.5 mg/g), while F. verticillioides and F. proliferatum growth rates were reduced at 0.98 a W at the highest chitosan dose used (2 mg/g). Since mycotoxins are unavoidable contaminants in food and feed chains, their presence needs to be reduced in order to minimize their effects on human and animal health and to diminish the annual market loss through rejected maize and wheat; in this scenario, pre-and post-harvest use of chitosan could be an important alternative.Fil: Zachetti, Vanessa Gimena Lourdes. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; ArgentinaFil: Cendoya, Eugenia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nichea, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; ArgentinaFil: Ramirez, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; Argentin

Seasonal variation in the content of mycotoxins in natural grasses devoted for cattle feed

Los problemas potenciales derivados de la contaminación con especies de Fusarium y sus micotoxinas en las pasturas naturales destinadas a la alimentación bovina han sido poco estudiados. Si bien el diagnóstico de las micotoxicosis es extremadamente difícil, internacionalmente se conoce que en zonas con climas templados los pastos, forrajes y ensilados ocasionalmente causan problemas en el ganado. Los efectos provocados por micotoxinas pueden reducir la productividad y, en ocasiones, provocar la muerte. Los trastornos clínicos se pueden presentar esporádicamente, pero son más frecuentes las intoxicaciones subclínicas, en las cuales las micotoxinas o sus metabolitos afectan los parámetros productivos, ocasionan inmunosupresión o persisten en la carne o en otros productos derivados, como la leche, razón por la cual deben ser considerados como un riesgo para la salud pública. En estudios previos realizados en nuestros laboratorios con el objetivo de detectar la presencia natural de zearalenona (ZEA) y sus derivados en pasturas naturales, hemos demostrado la presencia no solo de estas micotoxinas, sino de al menos otros cien metabolitos fúngicos entre micotoxinas, antibióticos y otros de acción desconocida. Entre las micotoxinas detectadas requieren especial atención los tricotecenos tipo A (toxina T-2, HT-2, neosolaniol), de toxicidad probada para ganado vacuno. Si bien no se detectó la presencia de aflatoxinas, sí se encontraron numerosos precursores que, por sus efectos tóxicos, son objeto de investigación en todo el mundo. Como consecuencia de estos resultados nos planteamos las siguientes hipótesis: a) existe una variación estacional en el contenido de micotoxinas tanto cualitativo como cuantitativo (tipo de micotoxinas y cantidad) en pasturas naturales destinadas a la alimentación de ganado bovino; b) además, hay una asociación entre el tipo de micotoxinas presentes naturalmente y el género y especie de las pasturas así como también las especies de Fusarium presentes. Para corroborar estas hipótesis se muestrearán pasturas naturales destinadas a la alimentación bovina en un establecimiento de la provincia del Chaco en distintas épocas del año (verano, otoño, invierno y primavera) y se les determinará la incidencia natural de micotoxinas por cromatografía líquida acoplada a espectrometría de masa (LC-MS/MS). Además, se aislarán e identificarán las especies de Fusarium presentes. Los resultados serán de utilidad para los productores, ya que les permitirán conocer qué tipo de pasturas naturales son de riesgo debido a la contaminación con micotoxinas y si existe una variación estacional en estas sustancias, lo que posibilitará hacer un manejo diferencial de las pasturas.Studies about potential problems arising from Fusarium and their mycotoxins contamination in natural grasses devoted to cattle feed are scarce. Globally, in areas with temperate climates, grass, fodder and silage occasionally cause problems in cattle. The effects caused by mycotoxins can reduce productivity and sometimes cause death, although the diagnosis is extremely difficult mycotoxicosis. Clinical disorders may occur occasionally but more often do subclinical intoxications, where mycotoxins or their metabolites affect growth performance, cause immunosuppression or persist in meat or other products, such as milk, and must be considered a public health risk. In a previous study we have demonstrated the natural occurrence of zearalenone and its derivatives, and also the presence of at least 100 other fungal metabolites among mycotoxins, antibiotics and others in natural pastures. Among these, type A trichothecenes (especially T-2 toxin, HT-2, neosolaniol), with proven toxicity to cattle, require special attention. We did not detect the presence of aflatoxins but we have found several biosynthetic precursors that, due to their toxic effects, are currently under research around the world. As a consequence of these results we have proposed the following hypotheses: a) there is a seasonal variation in both the qualitative and quantitative content of mycotoxins (mycotoxin type and quantity) in natural grasses devoted to cattle feed, and b) in addition, there is an association between the type of naturally occurring mycotoxins and genera/species of natural grasses as well as Fusarium species found. To corroborate these hypotheses, we will sample natural grasses intended for cattle feed in a farm located in Chaco province at different times of the year (summer, fall, winter and spring) and determine the natural occurrence of mycotoxins by HPLC-MS/MS. Furthermore we will identify the Fusarium species present. The results will be useful for farmers: knowing what kind of natural grasses pose a risk due to mycotoxins contamination and if there is a seasonal variation in these metabolites, they will be able to carry out a differential management.Fil: Ramirez, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Torres, Adriana Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Zachetti, Vanessa Gimena Lourdes. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Nichea, Maria Julia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Cendoya, Eugenia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Palacios, Sofia Alejendra. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin

Trichothecenes and zearalenone production by Fusarium equiseti and Fusarium semitectum species isolated from Argentinean soybean

Fusarium equiseti and F. semitectum represent the most abundant species in the Fusarium complex isolated from flowers, soybean pods and seeds in Argentina. The aim of the present study was to assess the production of major type A and type B trichothecenes (diacetoxyscirpenol, neosolaniol, T-2 toxin and HT-2 toxin, nivalenol, deoxynivalenol) and zearalenone by 40 F. equiseti and 22 F. semitectum isolates on rice culture. Mycotoxins were determined by HPLC with fluorescence detection after derivatisation with 1-anthronylnitrile for type A trichothecenes (i.e. diacetoxyscirpenol, neosolaniol, T-2 toxin and HT-2 toxin), by HPLC with UV detection for type B trichothecenes (i.e. nivalenol and deoxynivalenol) and by TLC for zearalenone. Twenty-two of 40 F. equiseti isolates produced diacetoxyscirpenol, nivalenol and ZEA alone or in combination, whereas only 2 of 20 F. semitectum isolates were nivalenol and ZEA producers. Both Fusarium species did not produce any deoxynivalenol, neosolaniol, T-2 toxin and HT-2 toxin. The variable retention in toxigenicity displayed by both fungal species suggests that these species have a saprophytic lifestyle in the soybean agroecosystem in Argentina.Fil: Barros, Germán Gustavo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Alaniz Zanon, Maria Silvina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Palazzini, Juan Manuel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Haidukowski, M.. b Institute of Sciences of Food Production; ItaliaFil: Pascale, M.. b Institute of Sciences of Food Production; ItaliaFil: Chulze, Sofia Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentin

Phylogenetic analyses of the Fusarium graminearum species complex isolated from soybean in Argentina and Brazil

Soybean is one of the most economically important crops in Argentina and Brazil. However, there is limited information on the biodiversity of the FGSC from soybean as compared to other crops of large-scale growing such as wheat and maize. A phylogenetic recognition of the Fusarium graminearum species complex (FGSC) isolated from soybean in Argentina and Brazil was performed in order to identify species responsible for trichothecene production. Sequences of genes encoding for the partial translation elongation factor, the 3-O-acetyltransferase and a putative reductase were analysed by the Maximum Parsimony method. Although the present study has focused on a limited number of isolates, this is the first report that provides evidence of the presence of at least four species within the FGSC associated with soybean in Argentina: F. graminearum sensu stricto, F. cortaderiae, F. meridionale and F. boothii. In addition, F. graminearum sensu stricto was detected for the first time among Brazilian isolates from soybean.Fil: Chiotta, María Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Alaniz Zanon, Maria Silvina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Giaj Merlera, Guillermo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Tessmann, D.. UNIVERSIDADE ESTADUAL DE MARINGÁ (UEM);Fil: Barros, Germán Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Chulze, Sofia Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentin

Pathogenicity of phylogenetic species in the Fusarium graminearum complex on soybean seedlings in Argentina

Soybean (Glycine max L.) is one of the main crops in Argentina. Most of the studies of pathogenicity in the Fusarium graminearum complex have focused on strains isolated from wheat and maize, and there is little information on strains isolated from soybean. Our objective in the present study was to compare the pathogenicity among soybean isolates of different phylogenetic species within the Fusarium graminearum complex on soybean seedlings under controlled conditions. Six strains representing three different phylogenetic species (F. graminearum, F. meridionale and F. cortaderiae) were identified by partial sequencing of the Translation Elongation Factor -1α gene (TEF-1) and evaluated for pathogenicity. All six strains reduced emergence, mainly by causing pre-emergence damping-off, seedling height and root dry weight and produced abnormal seedlings. The mean disease severity averaged across all isolates was approximately 3.0 in a 0–4 rating scale where 0 = healthy seedling and 4 = dead seedling. Significant differences in pathogenicity were observed among F. graminearum, F. meridionale and F. cortaderiae. These results are consistent with the hypothesis that different phylogenetic species within the Fusarium graminearum complex isolated from soybean are pathogenic under controlled conditions to soybean seedlings in Argentina. The present study demonstrates for the first time the pathogenic effect of F. meridionale on soybean in Argentina.Fil: Barros, Germán Gustavo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Alaniz Zanon, Maria Silvina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Chiotta, María Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Reynoso, Maria Marta. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Scandiani, María Mercedes. Laboratorio Agrícola Río Paraná, San Pedro; ArgentinaFil: Chulze, Sofia Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentin

Toxigenic profile and AFLP variability of Alternaria alternata and Alternaria infectoria occurring on wheat

The objectives of this study were to evaluate the ability to produce alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) by A. alternata and A. infectoria strains recovered from wheat kernels obtained from one of the main production area in Argentina; to confirm using AFLPs molecular markers the identify of the isolates up to species level, and to evaluate the intra and inter-specific genetic diversity of these two Alternaria species. Among all the Alternaria strains tested (254), 84% of them were able to produce mycotoxins. The most frequent profile of toxin production found was the co-production of AOH and AME in both species tested. TA was only produced by strains of A. alternata. Amplified fragment polymorphism (AFLPs) analysis was applied to a set of 89 isolates of Alternaria spp (40 were A. infectoria and 49 were A. alternata) in order to confirm the morphological identification. The results showed that AFLPs are powerful diagnostic tool for differentiating between A. alternata and A. infectoria. Indeed, in the current study the outgroup strains, A. tenuissima was consistently classified. Characteristic polymorphic bands separated these two species regardless of the primer combination used. Related to intraspecific variability, A. alternata and A. infectoria isolates evaluated seemed to form and homogeneous group with a high degree of similarity among the isolates within each species. However, there was more scoreable polymorphism within A. alternata than within A. infectoria isolates. There was a concordance between morphological identification and separation up to species level using molecular markers. Clear polymorphism both within and between species showed that AFLP can be used to asses genetic variation in A. alternata and A. infectoria. The most important finding of the present study was the report on AOH and AME production by A. infectoria strains isolated from wheat kernels in Argentina on a semisynthetic media for the first time. Also, specific bands for A. alternata and A. infectoria have been identified; these may be useful for the design of specific PCR primers in order to differentiate these species and to detect them in cereals