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  • Artículo
    Acceso Abierto
    Congruity of the Polymorphisms in the Expressed and Noncoding Parts of the Gli-B1 Locus in Common Wheat
    (2020) Popovych, Yulia; Chebotar, Sabina; Melnik, Viktor; Rodriguez Quijano, Marta; Pascual, Laura; Rogers, John William
    The previously defined pairs of primers GliB1.1 and GliB1.2 were found to produce three and four principal variants, respectively, of PCR sequence length for the -gliadin pseudogene in 46 Triticum aestivum L. cultivars from 15 countries carrying 19 known alleles at the Gli-B1 locus. A congruity was established between this polymorphism, allelic sets of the Gli-B1-produced gliadins (especially of the electrophoretic mobility in acid gels of the encoded -gliadin) and the presence in the wheat genotype of the Gli-B5b + Rg-1 allelic combination. Six different alleles at the Gli-B1 locus encoding an identical -gliadin produced a PCR sequence of about 400 bp (GliB1.1). Nine Gli-B1d-carrying genotypes from four countries produced an identical sequence of about 409 bp (GliB1.2), while three cultivars with Gli-B1h and four with Gli-B1b produced three and two specific sequences, respectively, of slightly di erent length. Allele Gli-B1j might be the result of recombination between coding and noncoding DNA sequences within the Gli-B1 locus. These observations imply that genetic diversity of the agriculturally important region of chromosome 1B marked by variants of the Gli-B1 locus is rather limited among common wheat cultivars of the 20th century, specifically to eight principal versions. These might have been incorporated into common wheat from diverged genotypes of diploid donor(s), and, due to the scarcity of recombination, subsequently maintained relatively intact. As well as its evolutionary significance, this information is of potential use in wheat breeding and we consider it likely that novel variants of the Gli-B1 locus will be found in hitherto unstudied germplasm.
  • Artículo
    Acceso Abierto
    Heteroalleles in Common Wheat
    (2021) Metakovsky, Eugene; Pascual, Laura; Vaccino, Patrizia; Melnik, Viktor; Rodriguez Quijano, Marta; Popovych, Yulia; Chebotar, Sabina; Rogers, John William
    The Gli-B1-encoded -gliadins and non-coding -gliadin DNA sequences for 15 different alleles of common wheat have been compared using seven tests: electrophoretic mobility (EM) and molecular weight (MW) of the encoded major -gliadin, restriction fragment length polymorphism patterns (RFLPs) (three different markers), Gli-B1- -gliadin-pseudogene known SNP markers (Single nucleotide polymorphisms) and sequencing the pseudogene GAG56B. It was discovered that encoded -gliadins, with contrasting EM, had similar MWs. However, seven allelic variants (designated from I to VII) differed among them in the other six tests: I (alleles Gli-B1i, k, m, o), II (Gli-B1n, q, s), III (Gli-B1b), IV (Gli-B1e, f, g), V (Gli-B1h), VI (Gli-B1d) and VII (Gli-B1a). Allele Gli-B1c (variant VIII) was identical to the alleles from group IV in four of the tests. Some tests might show a fine difference between alleles belonging to the same variant. Our results attest in favor of the independent origin of at least seven variants at the Gli-B1 locus that might originate from deeply diverged genotypes of the donor(s) of the B genome in hexaploid wheat and therefore might be called “heteroallelic”. The donor’s particularities at the Gli-B1 locus might be conserved since that time and decisively contribute to the current high genetic diversity of common wheat.
  • Comunicacion
    Acceso Abierto
    Presence of Fusarium graminearum sensu stricto associated with triticale (× Triticosecale Wittmack) in Argentina
    (2020) Dinolfo, María Inés; Martínez, Mauro; Castañares, Eliana; Stenglein, Sebastián
    Aim of study: To report the occurrence of Fusarium graminearum sensu stricto (s.s.) on triticale grains from field samples in Argentina and the potential mycotoxin production for these isolates. Area of study: Buenos Aires province, Argentina Material and methods: A total of 40 samples from different crops (barley, rye, triticale, and wheat) showing Fusarium head blight symptoms were taken during 2017/2018 harvest season. Colonies with colour and mycelium similar to Fusarium were taken and were morphologically and molecularly identified. The potential to produce deoxynivalenol, 15-acetyl deoxynivalenol and zearalenones was determined. Also, the Koch´s postulates were used to evaluate the pathogenic capacity of the F. graminearum s.s. isolates in triticale. Main results: Two Fusarium isolates were identified morphologically as F. graminearum, which were confirmed molecularly by PCR using the specific Fg16 F/R primers pair and by sequencing red and tri101 genes. The sequences obtained were compared with those available in the NCBI database using BLAST tools, showing 99-100% homology with those belonging to F. graminearum s.s. The results demonstrated that F. graminearum s.s. isolates were pathogenic when triticale spikes were inoculated by spraying under greenhouse conditions. Research highlights: To our knowledge, this is the first time that the presence of F. graminearum s.s. is reported associated with triticale in Argentina.
  • Artículo
    Acceso Abierto
    Cultivable soil fungi community response to agricultural management and tillage system on temperate soil
    (2021) Moreno, María Virginia; Casas, C.; Biganzoli, F.; Manso, L.; Silvestro, Luciana; Moreira, María Eugenia; Stenglein, Sebastián
    In agricultural soils, fungi constitute most of the total microbial biomass in the environment contributing with more than 50% of the soil biomass. The fungi should be considered as a link in the production not only by their attributes but also for their potential pathogenicity on crops chains. We aim to determine in what extent the combination of management styles and tillage systems control specific cultivable soil fungal community structure in temperate fertile Petrocalcic Argiudoll soil in a field experiment. We measured soil fungal richness, abundance and diversity along a one-year experiment (2009–2010). The plots were subjected to different tillage systems (conventional vs. zero) combined with different agricultural management histories (pasture/agriculture rotation vs. intensive agriculture). The measures were performed every three months along a year in three replicated plots. Rotation with pastures and zero tillage stimulated the saprophytic soil fungi community in detriment of pathogens. The clearest dissimilarity was given by the seasons. The results obtained from assay suggested that the seasons effect was strongest that the management or tillage on the soil fungal community.
  • Artículo
    Acceso Abierto
    Changes in soil biological properties in different management and tillage systems in petrocalcic argiudoll
    (2021) Moreno, María Virginia; Biganzoli, F.; Casas, C.; Manso, L.; Moreira, María Eugenia; Silvestro, Luciana
    We analyzed the effect of different tillage systems under different land-use histories, on biological properties of soil during one year. The experiment was carried out at a Petrocalcic Argiudoll of Tres Arroyos (Buenos Aires, Argentina). The specific aim was to describe and compare the soil organic carbon (SOC), the soil basal respiration (BR) and the activities of the enzyme dehydrogenase, urease and acid-phosphomonoesterase under zero and conventional tillage on soils under pasture and intensive agriculture. The SOC concentration was highest in summer (postharvest) independently of tillage system or land-use history. However, in autumn the plots under conventional tillage showed higher values of SOC than those with zero tillage, independently of land-use history. The BR had a significant benefit in favour of summer pasture soils. The effect of land-use history or the tillage system on the enzymes activity was dependent of sampling season. The soil enzymes were more sensible than SOC and BR. In temporal studies the effect of sampling season is strongest that others factors as tillage systems or land-use history.
  • Artículo
    Acceso Abierto
    Virulence and enzymatic activity of three new isolates of Beauveria bassiana (Ascomycota: Hypocreales) from the South American locust Schistocerca cancellata (Orthoptera: Acrididae)
    (2020) Pelizza, Sebastian A.; Medina, H.; Ferreri, N. A.; Elíades, Lorena; Pocco, Martina Eugenia; Stenglein, Sebastián; Lange, Carlos Ernesto
    Schistocerca cancellata is a large-sized acridid, which has historically represented the greatest agricultural problem in southern South America, causing serious economic losses. Since 2015 S. cancellata entered in a state of outbreak condition of historical proportions, producing frequent and large swarms of up to 25 km² in the north and central region of Argentina and areas of neigh boring Bolivia and Paraguay. At present, chemical insecticides are still the only means available for the control of S. cancellata. We analyzed under laboratory conditions the effectiveness of three fungal strains of Beauveria bassiana isolated from S. cancellata and also determined the relationship between chitinase, protease, and lipase levels at different temperatures of these fungi and their insecticidal activities. The pathogenicity assays were carried out by the sprayed method with concentrations of 1 × 10⁴, 1 × 10⁶ and 1 × 10⁸ conidia/ml. We observed that isolate LPSc 1227 caused the highest mortality at each dose studied, ranging from 100% at a dose of 1 × 10⁸ conidia/ml to 33.3 ± 3.2% at the lowest dose of 1 × 10⁴ conidia/ml. Moreover, in this isolate the highest values of chitinolytic and proteolytic activity were recorded (2.31 ± 0.31 and 1.78 ± 0.04), respectively.
  • Artículo
    Acceso Abierto
    Metabolic Profiling of Phloem Exudates as a Tool to Improve Bread-Wheat Cultivars
    (2018) Basile, Marisol; Burrell, Mike M.; Walker, Heather J.; Cardozo, Jorge A.; Steels, Chloe; Kallenberg, Felix; Tognetti, Jorge Alberto; Dalla Valle, Horacio R.; Rogers, John William
    In a proof of concept study aimed at showing that metabolites in bread wheat (Triticum aestivum L. ssp. aestivum), phloem exudates have potential as biochemical markers for cultivar discrimination, Argentinean cultivars from three quality groups (groups 1, 2, and 3 of high, intermediate, and low quality, respectively) were grown under two nitrogen (N) availabilities and analysed for metabolic profile by electrospray ionisation mass spectrometry. Data as signal strengths of mass/charge (m/z) values binned to a resolution of 0.2 Daltons were subjected to principal component analysis and orthogonal projections to latent structures discriminant analysis. Certain bins were influential in discriminating groups taken in pairs and some were involved in separating all three groups. In high N availability, group 3 cultivars clustered away from the other cultivars, while group 1 cultivars clustered tightly together; group 2 cultivars were more scattered between group 1 and group 3 cultivars. In low N availability, the cultivars were not clustered as tightly; nonetheless, group 1 cultivars tended to cluster together and mainly separated from those of group 2. m/z values also showed potential for discrimination between N availability. In conclusion, phloem exudate metabolic profiles could provide biochemical markers for selection during breeding and for discerning the effects of N fertiliser application.
  • Artículo
    Acceso Abierto
    Fusarium oxysporum, potencial agente de control biológico para Sorghum halepense en Argentina
    (2018) Stocco, Marina Celeste; Lampugnani, Gladys Adelma; Abramoff, Cecilia; Zuluaga, María Soledad; Stenglein, Sebastián; Acciaresi, Horacio Abel; Mónaco, Cecilia Inés
    El sorgo de Alepo (Sorghum halepense (L.) Pers.) es una de las especies de malezas perennes más importantes en el mundo. Hasta el momento, no se ha podido disminuir su propagación e incidencia en los sistemas agrícolas. El biocontrol es una posible alternativa de manejo de malezas. El objetivo del trabajo fue evaluar por primera vez en Argentina, el efecto de diferentes técnicas de aplicación de Fusarium oxysporum sobre el crecimiento aéreo y subterráneo del sorgo de Alepo. Además, se estudió la acción del patógeno sobre la germinación de semillas de maíz, girasol, soja y sorgo granífero, teniendo en cuenta que podría afectar a estos cultivos. Se utilizaron dos técnicas de aplicación del patógeno. La aplicación de una suspensión de esporas de F. oxysporum en suelo (técnica liquida) mostró que a los tres meses se había producido la muerte del total de las plantas, mientras que con la técnica de infestación del suelo con un cultivo sólido del patógeno (técnica sólida) a los 90 días sólo había muerto el 65% de las plantas. F. oxysporum no disminuyó el porcentaje de germinación de los cultivos de soja, girasol, sorgo granífero y maíz, por lo que este hongo podría utilizarse como agente de biocontrol del sorgo de Alepo. Sin embargo, es necesario conocer el rango de hospedantes del patógeno para poder evaluar los riesgos de usar este antagonista.
  • Artículo
    Embargado
    Pseudocercospora griseola Causing Angular Leaf Spot on Phaseolus vulgaris Produces 1,8-Dihydroxynaphthalene-Melanin
    (2009) Saparrat, Mario; Fermoselle, Geraldine; Stenglein, Sebastián; Aulicino, Mónica B.; Balatti, Pedro Alberto
    Pseudocercospora griseolais the causal agent of angular leaf spot of common bean (ALS). It has undergone parallel coevolution with its host and two major groups have been defined, “Andean” (P. griseolaf.griseola) and “Mesoamerican” (P. griseolaf.mesoamericana). The aim of this study was to analyze the nature and the level of the dark pigment synthesized by the representatives of each group. After 21days of incubation on potato dextrose agar medium,P. griseolaf. griseolaisolate S3b developed colonies with diameters of 17.5±1.3mm and concentric rings of pigmentation. Isolate T4 ofP. griseolaf.mesoamericanapresented smaller colonies (9.9±0.3mm) with a uniform dark-gray color. Both isolates, S3b and T4, produced the same pigment, a 1,8-dihydroxynaphthalene-melanin, although different in quantity and structural features as suggested by the IR spectrum. TheP. griseolaf. griseolaisolate S3b had a higher growth rate and melanin content as well as smaller sensitivity to melanin synthesis inhibitors compared to the isolate T4 ofP. griseolaf.mesoamericana. These results suggest a possible link between melanin and growth inP. griseola.
  • Artículo
    Embargado
    Quality and endosperm storage protein variation in Argentinean grown bread wheat
    (2009) Lerner, S.E.; Kolman, M.A.; Rogers, John William
    Genetic variability for endosperm storage proteins was analysed in 119 Argentinean grown bread wheat cultivars. For the HMW-GS, three, six and two alleles were observed at theGlu-A1,Glu-B1andGlu-D1loci, respectively, in 17 allelic combinations. The majority of these combinations were considered to be associated with good quality. For the LMW-GS, eight, seven and four alleles were provisionally observed at theGlu-A3,Glu-B3andGlu-D3loci, respectively, in 51 allelic combinations. Regarding quality, the alleles present atGlu-D3were mainly those previously shown to be associated with good quality, whereas atGlu-A3andGlu-B3, some alleles previously associated with poor quality were present at high frequency. Relatively few cultivars carried combinations for all the loci studied that would be expected to be associated with high quality. The mean genetic variation index (H) observed for the glutenin loci (0.589) was similar to values observed in other collections. Unweighted pair-group method using arithmetic averages (UPGMA) of the six loci plus the Chinese Spring-Cheyenne CSS–CNN difference showed that the 119 cultivars fell into 93 distinct combinations. For complete discrimination between all cultivars they would have to be analysed for additional loci. There remains scope for varietal quality improvement within this germplasm pool.
  • Artículo
    Embargado
    Fusarium proliferatum, a New Pathogen Causing Head Blight on Oat in Argentina
    (2010) Stenglein, Sebastián; Dinolfo, María Inés; Moreno, María Virginia; Galizio, R.; Salerno, G.L.
    Oat (Avena sativaL.) is widely grown (~200,000 ha) for livestock feed in Argentina.Fusariumspp. affect yield and commercial quality and can cause indirect losses because someFusariumspp. produce mycotoxins. In December 2008, a study of oat seeds (cv. Graciela INTA) from Trenque Lauquen, Buenos Aires, Argentina was conducted. Seeds (400) were surface sterilized by dipping successively into 70% ethanol for 2 min, 5% sodium hypochlorite for 2 min, rinsed twice in fresh sterilized distilled water, plated on 2% potato dextrose agar (PDA) pH 6, and incubated at 24 ± 2°C with 12-h photoperiods. Six isolates morphologically similar toFusariumspp. were observed after 6 days of incubation. For identification, monosporic isolates were transferred onto 2% PDA and carnation leaf agar (CLA) to grow with the conditions described above. Two isolates produced abundant, white, aerial mycelium and violet-to-dark (with age) pigments in the PDA. On CLA, macroconidia were abundant, slender, almost straight, thin walled, and usually three to five septate. Microconidia were abundant, usually single celled, oval or club-shaped in chains (less commonly in false heads) on monophialides and polyphialides. Chlamydospores were absent. The fungus was identified asFusarium proliferatum(Matsushima) Nirenberg on the basis of fungal morphology (1). To complete Koch's postulates, the pathogenicity of the fungus was tested by spraying five healthy inflorescences of oat (cv. Graciela INTA) with a 5-ml suspension (2 × 105conidia/ml). Another two healthy inflorescences were sprayed with sterile distilled water. Plants were placed in a growth chamber with a 12-h photoperiod at 22 ± 2°C and covered with polyethylene bags that were removed after 3 days and plants were moved to a glasshouse. This procedure was repeated. While control inflorescences were asymptomatic, inoculated inflorescences showed bleaching glumes that sometimes became necrotic with some grains that presented pale brown discoloration and necrotic areas. The fungus was reisolated from glumes and grains of inoculated plants and not from controls using the methodology described above. To confirm the morphological diagnosis, the genomic DNA of the isolates was extracted (3) and a PCR reaction with specific primers 5′-CTTTCCGCCAAGTTTCTTC-3′-forward and 5′-TGTCAGTAACTCGACGTTGTTG-3′-reverse was chosen (2) using the following cycling protocol: initial denaturation step at 95°C for 2 min; 30 cycles at 95°C for 30 s, 55°C for 30 s, 72°C for 45 s; final extension at 72°C for 2 min. Successful amplifications were confirmed by gel electrophoresis. Size of the DNA fragment was estimated using a 100-bp DNA ladder. The reaction was repeated three times. The expected size product (585 bp) was obtained, confirming the identification (2). To our knowledge, this is the first report ofF. proliferatumon oat in Argentina. This species is known to produce fumonisins, beauvericin, fusaric acid, fusarins, and moniliformin toxins, among others. SinceF. proliferatumcan infect different cereal grains, a large-scale survey in the same and different fields is in progress. A voucher culture has been deposited in the LPSC (Culture Collection of the La Plata Spegazzini Institute) No. 1058.
  • Artículo
    Embargado
    Phylogenetic relationships of Fusarium poae based on EF-1 alpha and mtSSU sequences
    (2010) Stenglein, Sebastián; Rodriguero, M.S.; Chandler, E.; Jennings, P.; Salerno, G.L.; Nicholson, P.
    A molecular phylogenetic analysis ofFusarium poaeisolates from South America (Argentina) and Europe (mainly England, Germany, Italy) was performed using 98F. poae, fourFusarium culmorum, twoFusarium sporotrichioidesand oneFusarium langsethiaeisolates. Phylogenetic analyses were performed using nuclear (translation elongation factor 1-alpha,EF-1α) and mitochondrial (mitochondrial small subunit rDNA,mtSSU) sequences. Partitioned (each dataset separately) and combined (EF-1α+mtSSU) analyses did not reveal any clear correlations from the inferred branching topology, between the distribution of observed haplotypes and the geographic origin and/or host species. Results from the present study confirmed that isolates fromF. poaeform a monophyletic group, and the low variability within isolates from a broad geographic range suggests a common lineage history. AmongF. poaeisolates from Argentina, however, some were found to possess an insert withinmtSSUwith structural similarities to group IC2 introns.F. poaeisolates differing by the presence/absence of amtSSUinsertion were characterized further by analysis of a portion of theTri5gene, but this sequence was unable to reveal variability. The presence of this insert only within isolates from Argentina suggests that evolutionary events (insertions/deletions) are probably taking place within the ArgentinianF. poaeisolates, and that the acquisition of this insert occurred after geographic isolation of the Argentinian and European populations.
  • Artículo
    Acceso Abierto
    Comparison of low molecular weight glutenin subunits identified by SDS-PAGE, 2-DE, MALDI-TOF-MS and PCR in common wheat
    (2010) Liu, Li; Ikeda, Tatsuya M.; Branlard, Gerard; Peña, Roberto J.; Rogers, John William; Lerner, Silvia E.; Kolman, Maía de Los Angeles; Xia, Xianchun; Wang, Linhai; Ma, Wujun; Appels, Rudi; Yoshida, Hisashi; Wang, Aili; Yan, Yueming; He, Zhonghu
    Background Low-molecular-weight glutenin subunits (LMW-GS) play a crucial role in determining end-use quality of common wheat by influencing the viscoelastic properties of dough. Four different methods - sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), two-dimensional gel electrophoresis (2-DE, IEF × SDS-PAGE), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and polymerase chain reaction (PCR), were used to characterize the LMW-GS composition in 103 cultivars from 12 countries. Results At theGlu-A3locus, all seven alleles could be reliably identified by 2-DE and PCR. However, the allelesGlu-A3eandGlu-A3dcould not be routinely distinguished fromGlu-A3fandGlu-A3g, respectively, based on SDS-PAGE, and the alleleGlu-A3acould not be differentiated fromGlu-A3cby MALDI-TOF-MS. At theGlu-B3locus, allelesGlu-B3a,Glu-B3b,Glu-B3c,Glu-B3g,Glu-B3handGlu-B3jcould be clearly identified by all four methods, whereasGlu-B3ab,Glu-B3ac,Glu-B3adcould only be identified by the 2-DE method. At theGlu-D3locus, allelic identification was problematic for the electrophoresis based methods and PCR. MALDI-TOF-MS has the potential to reliably identify theGlu-D3alleles. Conclusions PCR is the simplest, most accurate, lowest cost, and therefore recommended method for identification ofGlu-A3andGlu-B3alleles in breeding programs. A combination of methods was required to identify certain alleles, and would be especially useful when characterizing new alleles. A standard set of 30 cultivars for use in future studies was chosen to represent all LMW-GS allelic variants in the collection. Among them, Chinese Spring, Opata 85, Seri 82 and Pavon 76 were recommended as a core set for use in SDS-PAGE gels.Glu-D3candGlu-D3eare the same allele. Two new alleles, namely,Glu-D3min cultivar Darius, andGlu-D3nin Fengmai 27, were identified by 2-DE. Utilization of the suggested standard cultivar set, seed of which is available from the CIMMYT and INRA Clermont-Ferrand germplasm collections, should also promote information sharing in the identification of individual LMW-GS and thus provide useful information for quality improvement in common wheat.
  • Informe técnico
    Acceso Abierto
    Catalogue of gene symbols for wheat: 2011 Supplement
    (2010) McIntosh, R. A.; Dubcovsky, J.; Rogers, John William; Morris, C. F.; Appels, R.; Xia, X.C.
    The most recent version of the Catalogue, compiled for the 11th International Wheat Genetics Symposium held in Brisbane, Australia, and the 2009 and 2010 Supplements (Annual Wheat Newsletter 55 and 56) are available on the Komugi and GrainGenes websites. It was not included as part of the IWGS proceedings and therefore cannot be cited as part of them
  • Artículo
    Acceso Abierto
    Common Bean germplasm molecular analysis: a biotechnological approach for breeding
    (2010) Galván, M.; Stenglein, Sebastián; Balatti, Pedro Alberto
    Argentina, which is a major producer of common bean (Phaseolus vulgaris L.), represents the southern most limit of the Andean diversification center of the species. The diverse environmental conditions of these places and human selection favored the development of a great variability of wild beans and landraces, which is endangered due to the destruction of habitats by forest exploitation and agriculture. Information on the variability of these resources is essential to set conservation strategies and design breeding programs aimed at enlarging the genetic base of commercial beans. This work is an overview of the marker-based studies on landraces and wild bean genetic diversity, with special emphasis on Argentinean beans, as a first step for the optimal exploitation of the naturally available bean genetic resources, to generate new traits and improve crop performance. The identification of diversity and hybridization between populations is enhanced by the application of the new tools and the information generated by bean genomic research. Gene flow, which appears to occur fairly frequently in bean, has to be studied in more detail in this region in order to facilitate the transfer of useful alleles from the unexploited germplasm to improved lines, broadening the genetic diversity available for breeding. Some resistance gene analogs (RGAs) have been described within the Andean gene pool and only a few have been functionally characterized or linked to a phenotype. Therefore, a strategy for the exploitation of bean germplasm variability based on the detection of RGAs is also mentioned, though more work should be devoted at identifying these sequences in Andean landraces and wild beans.
  • Artículo
    Acceso Abierto
    Natural Contamination with Mycotoxins Produced by Fusarium graminearum and Fusarium poae in Malting Barley in Argentina
    (MDPI (Multidisciplinary Digital Publishing Institute), 2018) Nogueira, María Soledad; Decundo, Julieta; Martínez, Mauro; Dieguez, Susana Nelly; Moreyra, Federico; Moreno, María Virginia; Stenglein, Sebastián
    Two of the most common species of toxin-producing Fusarium contaminating small cereal grains are Fusarium graminearum and F. poae; with both elaborating diverse toxins, especially deoxynivalenol (DON) and nivalenol (NIV), respectively. The objective of our work during the 2012–2014 growing seasons was to screen crops for the most commonly isolated Fusarium species and to quantify DON and NIV toxins in natural malting-barley samples from different producing areas of Argentina. We identified 1180 Fusarium isolates in the 119 samples analyzed, with 51.2% being F. graminearum, 26.2% F. poae and 22.6% other species. We found high concentrations of mycotoxins, at maximum values of 12 μg/g of DON and 7.71 μg/g of NIV. Of the samples, 23% exhibited DON at an average of 2.36 μg/g, with 44% exceeding the maximum limits (average of 5.24 μg/g); 29% contained NIV at an average of 2.36 μg/g; 7% contained both DON and NIV; and 55% were without DON or NIV. Finally, we report the mycotoxin contamination of the grain samples produced by F. graminearum and F. poae, those being the most frequent Fusarium species present. We identified the main Fusarium species affecting natural malting-barley grains in Argentina and documented the presence of many samples with elevated concentrations of DON and NIV. To our knowledge, the investigation reported here was the first to quantify the contamination by Fusarium and its toxins in natural samples of malting barley in Argentina.
  • Artículo
    Embargado
    ISSR markers detect high genetic variation among Fusarium poae isolates from Argentina and England
    (2010) Dinolfo, María Inés; Stenglein, Sebastián; Moreno, María Virginia; Nicholson, Paul; Jennings, Philip; Salerno, Graciela L.
    Fusarium poae is one of the Fusarium species isolated from cereal grains infected by Fusarium head blight (FHB), and in recent years it has been identified as a major FHB component. In this study, 97 F. poae isolates from Argentina (n=62) and England (n=35) were analysed by inter-simple sequence repeats (ISSR) to examine the genetic diversity and to determine whether intraspecific variation could be correlated with geographic and/or host origin. The molecular analysis showed high intraspecific variability within F. poae isolates, but did not reveal a clear relationship between variability and the host/geographic origin. Fusarium poae isolates from the same geographic region or host appeared in different subclusters. Conversely, isolates with the same haplotype were also collected from different geographic regions. However, we did observe subclusters consisting of isolates from Argentina only or from England only. Furthermore, a single seed sample was found to host different haplotypes. Analysis of molecular variance (AMOVA) indicated a high genetic variability in F. poae, with most of the genetic variability explained by differences within, rather than between Argentinean and English populations. This is the first report on genetic diversity of F. poae using ISSR markers. Moreover, ISSR fingerprinting generates highly polymorphic markers for F. poae and proved to be a useful and reliable assay for genetic variability studies.
  • Artículo
    Acceso Abierto
    Canaryseed (Phalaris canariensis L.) accessions from nineteen countries show useful genetic variation for agronomic traits
    (2010) Cogliatti, Maximiliano; Bongiorno, F.; Dalla Valle, H.; Rogers, John William
    Fifty-seven accessions of canaryseed (47 populations and 10 cultivars) from 19 countries were evaluated for agronomic traits in four field trials sown over 3 yr in the province of Buenos Aires, Argentina. Genetic variation was found for all traits scored: grain yield and its components (grain weight, grain number per square meter, grain number per head and head number per square meter), harvest index, percent lodging, and phenological characters (emergence to heading, emergence to harvest maturity and heading to harvest maturity). Although genotype×environment interaction was observed for all traits, the additive differences between accessions were sufficient to enable promising breeding materials to be identified. Accessions superior in performance to the local Argentinean population, which in general gave values close to the overall mean of the accessions evaluated, were identified. For example, a population of Moroccan origin gave good yield associated with elevated values of the highly heritable character grain weight, rather than with the more commonly observed grain number per square meter. This population was also of relatively short stature and resistant to lodging, and, although it performed best when sown within the normal sowing date, tolerated late sowing fairly well. Other accessions were also observed with high grain weight, a useful characteristic in itself, since large grains are desirable from a quality point of view. Regarding phenology, the accessions showed a range of 160 degree days (8 calendar days in our conditions) in maturity, which, while not large in magnitude, may be of some utility in crop rotation management. Some accessions were well adapted to late sowing. Grain yield in general was strongly correlated with grain number per square meter. Principal components analysis (PCA) carried out for all characteristics provided indications of accessions combining useful characteristics and identified three components that explained approximately 70% of the phenotypic variation. Furthermore, a second PCA plus regression showed that approximately 60% of the variation in grain yield could be explained by a component associated with harvest index and grain number per square meter. Pointers were provided to possible future breeding targets.
  • Artículo
    Acceso Abierto
    First record of Fusarium verticillioides as an entomopathogenic fungus of grasshoppers
    (2011) Pelizza, S.A.; Stenglein, Sebastián; Cabello, Marta Noemí; Dinolfo, María Inés; Lange, Carlos Ernesto
    Fusarium verticillioides(Saccardo) Nirenberg (Ascomycota: Hypocreales) is the most common fungus reported on infected corn kernels and vegetative tissues, but has not yet been documented as being entomopathogenic for grasshoppers. Grasshoppers and locusts represent a large group of insects that cause economic damage to forage and crops.Tropidacris collaris(Stoll) (Orthoptera: Acridoidea: Romaleidae) is a large and voracious grasshopper that in recent years has become an increasingly recurrent and widespread pest in progressively more greatly extended areas of some of in Argentina’s northern provinces, with chemical insecticides being currently the only means of control. During February and March of 2008-09, nymphs and adults ofT. collariswere collected with sweep nets in dense woodland vegetation at a site near Tres Estacas in western Chaco Province, Argentina, and kept in screened cages.F. verticillioideswas isolated from insects that died within 10 days and was cultured in PGA medium. Pathogenicity tests were conducted and positive results recorded. Using traditional and molecular-biological methods, an isolate ofF. verticillioideswas obtained fromT. collaris, and its pathogenecity in the laboratory was shown against another harmful grasshopper,Ronderosia bergi(Stål) (Acridoidea: Acrididae: Melanoplinae). The mortality caused byF. verticillioidesonR. bergireached 58 ± 6.53% by 10 days after inoculation. This is the first record of natural infection caused byF. verticillioidesin grasshoppers.
  • Artículo
    Acceso Abierto
    Diversity of Pyrenophora tritici-repentis isolates from the Argentinian wheat growing area: morphocultural and pathogenic analysis
    (2011) Moreno, María Virginia; Arambarri, A.M.; Perelló, Analía
    heat is currently considered as one of the most important crops world-wide. Among the fungal diseases of this crop, tan spot produced byPyrenophora tritici-repentisis one of the most important. Tan spot increased its incidence, prevalence and severity in Argentina and South America. The aim of this work was to generate information about the morphocultural and pathogenic variability on wheat cultivars from Argentina. The results showed that isolates ofP. tritici-repentis, originated from diverse localities of Argentina differed in their morphocultural characteristics and in their level of severity. The cluster analysis of morphocultural characteristics among 155 isolates of the pathogen defined 44 morphotypes according with the Jaccard’s coefficient (CCC=0.79). Pathogenicity tests determined on a set of eight wheat cultivars under greenhouse conditions showed the presence of physiological specialization in 33 isolates ofP. tritici-repentis. The efforts to link morphocultural and pathogenicity features to the geographical origin of the isolates were mostly unsuccessful. The isolates tested appeared in different groups and most of the isolates which shared the highest similarity coefficient were collected from different localities and different wheat cultivars.