Adriana Torres | Universidad Nacional de Rio Cuarto (original) (raw)

Papers by Adriana Torres

Pathogens, May 19, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Mycotoxin Research, Sep 1, 1990

The deoxynivalenol and nivalenol contamination in wheat and by-products obtained through milling ... more The deoxynivalenol and nivalenol contamination in wheat and by-products obtained through milling was analized by Trucksess method slightly modified in the proportion of acetonitrile-water (3: 11. Only one sample of wheat showed deoxynivalenol contamination, 1,200~g/kg. No samples obtained in different stages of the milling were contaminated with deoxynivalenol or nivalenol. In the commercial wheat flours the levels found ranged between 400 and 800~g/kg, as follows: 400~g/kg, 5 samples; 800~g/kg, 1 sample.

Food additives and contaminants, Oct 1, 2007

Gibberella zeae (anamorph Fusarium graminearum) causes Fusarium head blight of wheat. The authors... more Gibberella zeae (anamorph Fusarium graminearum) causes Fusarium head blight of wheat. The authors used amplified fragment length polymorphisms (AFLPs) to characterize the genetic structure of two G. zeae populations from commercial wheat fields. The working hypothesis was that sufficient genetic exchange occurs between local populations to prevent significant partitioning of allelic variation. We analysed 216 AFLP loci for 113 isolates

Biological Control, Dec 1, 2009

Fusarium head blight (FHB) caused by Gibberella zeae (anamorph = Fusarium graminearum) is a devas... more Fusarium head blight (FHB) caused by Gibberella zeae (anamorph = Fusarium graminearum) is a devastating disease that causes extensive yield and quality losses to wheat in humid and semi-humid regions of the world. Biological control has been demonstrated to be effective under laboratory conditions but a few biocontrol products have been effective under field conditions. The improvement in the physiological quality of biocontrol agents may improve survival under field conditions, and therefore, enhance biocontrol activity. Bacillus subtilis RC 218 and Brevibacillus sp. RC 263 were isolated from wheat anthers and showed significant effect on control of FHB under greenhouse assays. This study showed the effect of water availability measured as water activity (a W) using a growth medium modified with NaCl, glycerol and glucose on: (i) osmotic stress tolerance, (ii) viability in modified liquid medium, (iii) quantitative intracellular accumulation of betaine and ectoine and (iv) the biocontrol efficacy of the physiologically improved agents. Viability of B. subtilis RC 218 in NaCl modified media was similar to the control. Brevibacillus sp. RC 263 showed a limited adaptation to growth in osmotic stress. Betaine was detected in high levels in modified cells but ectoine accumulation was similar to the control cells. Biocontrol activity was studied in greenhouse assays on wheat inoculated at anthesis period with F. graminearum RC 276. Treatments with modified bacteria reduced disease severity from 60% for the control to below 20%. The physiological improvement of biocontrol agents could be an effective strategy to enhance stress tolerance and biocontrol activity under fluctuating environmental conditions.

International Journal of Food Microbiology, May 1, 2015

Fusarium proliferatum is a member of the Fusarium fujikuroi species complex (FFSC) involved in th... more Fusarium proliferatum is a member of the Fusarium fujikuroi species complex (FFSC) involved in the maize ear rot together with Fusarium verticillioides, which is a very closely related species. Recently, different studies have detected natural fumonisin contamination in wheat kernels and most of them have shown that the main species isolated was F. proliferatum. Fusarium strains obtained from freshly harvested durum wheat samples (2008 to 2011 harvest seasons) from Argentina were characterized through a phylogenetic analysis based on translation elongation factor-1 alpha (EF-1α) and calmodulin (CaM) genes, determination of mating type alleles, and evaluation of fumonisin production capability. The strains were identified as F. proliferatum (72%), F. verticillioides (24%) and other Fusarium species. The ratio of mating type alleles (MAT-1 and MAT-2) obtained for both main populations suggests possible occurrence of sexual reproduction in the wheat fields, although this seems more frequent in F. proliferatum. Phylogenetic analysis revealed greater nucleotide variability in F. proliferatum strains than in F. verticillioides, however this was not related to origin, host or harvest year. The fumonisin-producing ability was detected in 92% of the strains isolated from durum wheat grains. These results indicate that F. proliferatum and F. verticillioides, among the fumonisin producing species, frequently contaminate durum wheat grains in Argentina, presenting a high risk for human and animal health.

Food additives and contaminants, 1997

ABSTRACT

Springer eBooks, 2009

Page 1. Chapter 12 Fusarium and Fumonisins in Maize in South America Adriana M. Torres, Maria L. ... more Page 1. Chapter 12 Fusarium and Fumonisins in Maize in South America Adriana M. Torres, Maria L. Ramirez, and Sofia N. Chulze 12.1 Introduction South America, with its considerable North-South extent, is subject to climates ...

International Journal of Food Microbiology, May 1, 2021

Fusarium Head Blight (FHB) is a very important fungal disease that affects small grain cereals wo... more Fusarium Head Blight (FHB) is a very important fungal disease that affects small grain cereals worldwide. This disease not only causes yield loses but also crops contamination with mycotoxins such as deoxynivalenol (DON) and nivalenol (NIV). Species within the Fusarium graminearum species complex have been described as the main causal agents of this disease, however lately there have been few reports of Fusarium cerealis causing the disease in wheat and barley in different parts of the world. This study evaluated the aggressiveness of F. cerealis to durum wheat cultivars and also mycotoxin production in planta. Moreover, the mycotoxin profile of F. cerealis strains was characterized molecularly and chemically. All durum wheat cultivars showed typical FHB symptoms but the disease severity varied among them in levels up to 66%. In addition, seventeen different compounds were detected in the infected heads including DON, NIV and nivalenol-3-β-d-glucose (NIV3G). NIV was detected in all cultivars and was the most produced mycotoxin with levels ranging from 1.04 to 6.8 mg/kg. On the other hand, the molecular analysis of F. cerealis strains showed that all of them possessed NIV genotype while the chemical assessment showed that the strains were able to produce not only this toxin in vitro but also DON, zearalenone and other twenty-one secondary metabolites. The increasing incidence of F. cerealis and the possible contamination of crops with the mycotoxins that it produces are of great concern for food security and world cereal trade since it has been reported that NIV is more toxic for humans and animals than DON.

Mycotoxin Research, Mar 1, 1999

A study was carried out to evaluate the effect of heat treatment on the stability of alternariol ... more A study was carried out to evaluate the effect of heat treatment on the stability of alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TEA) in sunflower flour and the effectiveness of this treatment by a biological assay in rats. The concentrations of AOH and AME remained constant during heating at 100~ for up to 90 minutes while TeA concentration decreased with time to 50% after 90 minutes. The most effective treatment in reducing AOH and AME levels was heating at 121gC for 60 minutes. Histopathological evaluation in the biological assay in rats fed with Alternaria toxins showed marked atrophy and fusion of villi in the intestines and liver cell damage; these lesions were less severe in rats fed heat-treated sunflower flour in line with the reduced toxin content. However, a lower weight gain and a noticeable renal damage in rats were produced when they fed decontaminated flour.

Food Research International, Aug 1, 2014

Peanut or groundnut (Arachis hypogaea L.) is cultivated in the tropical and warm temperate region... more Peanut or groundnut (Arachis hypogaea L.) is cultivated in the tropical and warm temperate regions of the world. Its production reaches approximately 39.9 million metric tons per year. The major producers/exporters of peanuts are the United States, Argentina, Sudan, Senegal, and Brazil. One of the major problems in peanut production worldwide is the contamination with Aspergillus section Flavi and aflatoxins, being these mycotoxins of great concern due to their toxicological effects to human and animals. Different strategies both at pre-harvest and post-harvest stages have been applied to reduce the entry of aflatoxins to the food and feed chains. Nowadays, no single strategy is enough to solve this problem. An integrate management from the field until food or feed processing is necessary to reduce the impact of aflatoxins. This review summarizes the advance in reducing the impact of aflatoxins in different countries where peanuts are cultivated.

Journal of Food Protection, Oct 1, 1995

A survey of 150 sunflower-seed samples was carried out to evaluate the contamination from infecti... more A survey of 150 sunflower-seed samples was carried out to evaluate the contamination from infection with Altemaria altemata with altemariol (AOH), altemariol monomethyl ether (AME) and tenuazonic acid (T A). A high percentage of the samples was contaminated with AOH (85%), AME, (47%), and TA (65%). The average levels detected were 187 Ilg/kg for AOH, 194 Ilg/kg for AME, and 6,692, Ilg/kg forT A. When sunflower seeds fermented by Alternaria altemata were processed under laboratory conditions to obtain the oil and meal, different distributions of Altemaria toxins between the oil and the meal were observed: whereas AOH, AME, and TA were detected in the meal, only AME and TA were detected in the oil, and the latter in a low percentage.

Toxins, Dec 13, 2021

Food additives and contaminants, Nov 1, 2004

The increased sphinganine/sphingosine (SA/SO) ratio has previously been shown as a biomarker of f... more The increased sphinganine/sphingosine (SA/SO) ratio has previously been shown as a biomarker of fumonisin exposure in experimental animals and has been proposed as a tool to assess human exposure to fumonisin mainly occurring through the dietary consumption of fumonisin contaminated maize-based foods. Sphinganine and sphingosine were measured in urines of humans resident in two areas of North Argentina and South Brazil with high maize consumption and compared with urine samples collected in areas with very low or no maize consumption, such as Central Argentina and Southern Italy. The pattern of SA/SO values in the two groups with no maize consumption (assumed as controls) was similar, with all SA/SO values lower than one. Mean SA/SO ratio was 1.27 in urine of subjects with high maize consumption (n ¼ 123) and 0.36 in controls (n ¼ 66) and the difference was statistically significant (p<0.001). The mean fumonisin level in maize samples collected in North Argentina and South Brazil was 0.35 mg kg À1 (n ¼ 40). Although a similar maize and fumonisin intake was recorded for the two groups of populations, the mean SA/SO ratio in South Brazil (1.57) was significantly higher (p<0.05) than that of North Argentina (0.69). These data suggest that the higher SA/SO values observed in South Brazil cannot be associated with high fumonisin exposure and further studies are necessary to provide convincing evidence for using the SA/SO ratio as a biomarker of human fumonisin exposure.

Applied and Environmental Microbiology, Dec 1, 2000

Strains of Fusarium species belonging to section Liseola cause stalk and ear rot of maize and pro... more Strains of Fusarium species belonging to section Liseola cause stalk and ear rot of maize and produce important mycotoxins, such as fumonisins. We isolated two species, Fusarium verticillioides (Gibberella fujikuroi mating population A) and Fusarium proliferatum (G. fujikuroi mating population D) from maize cultivated under no-till conditions at five locations in the Córdoba province of Argentina. We determined the effective population number for mating population A (N e) and found that the N e for mating type was 89% of the count (total population) and that the N e for male or hermaphrodite status was 36%. Thus, the number of strains that can function as the female parent limits N e , and sexual reproduction needs to occur only once every 54 to 220 asexual generations to maintain this level of sexual fertility. Our results indicate that the fungal populations isolated from no-till maize are similar to those recovered from maize managed with conventional tillage. We placed 36 strains from mating population A into 28 vegetative compatibility groups (VCGs). Of the 13 strains belonging to five multimember VCGs, only 2 isolates belonging to one VCG were clones based on amplified fragment length polymorphism (AFLP) fingerprints. Members of the other four multimember VCGs had an average similarity index of 0.89, and members of one VCG were no more closely related to other members of the same VCG than they were to other members of the population as a whole. This finding suggests that the common assumption that strains in the same VCG are either clonal or very closely related needs to be examined in more detail. The variability observed with AFLPs and VCGs suggests that sexual reproduction may occur more frequently than estimated by N e .

Fil: Ramirez, Maria Laura. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina.... more Fil: Ramirez, Maria Laura. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas, Fisicoquimicas y Naturales. Departamento de Microbiologia e Inmunologia; Argentina

Mycologia, Dec 6, 2021

Supplementary Figure 1. Most-parsimonious tree inferred by maximum parsimony (MP) analysis of par... more Supplementary Figure 1. Most-parsimonious tree inferred by maximum parsimony (MP) analysis of partial sequence of the TEF1 and RPB2 genes, showing that F. chaquense sequences form an exclusive clade that is distinct from the exclusive clade formed by F. armeniacum sequences. Branch lengths are indicated by the scale at the bottom of the figure. Maximum likelihood (ML) analysis yielded a tree with the same topology as the MP tree. Values above internodes are MP/ML bootstrap values >50%. The tree is rooted with sequence from F. proliferatum ITEM 2287. The number of Parsimony-Informative Characters (PIC), Retention Index (RI) and Consistency Index (CI) are indicated. Five 5-digit numbers following species names are NRRL strain numbers. T= type strain.

Cereal Research Communications, Sep 1, 1997

Tropical Plant Pathology, 2021

Nothopassalora personata is a cosmopolitan plant pathogenic fungus that causes late leaf spot (LL... more Nothopassalora personata is a cosmopolitan plant pathogenic fungus that causes late leaf spot (LLS) of peanut, the main foliar diseases of this crop. The disease emerged during the last decade in the USA and Argentina. Severely affected plants are early defoliated and yield is decreased by 40–50%. During the last decades, effective LLS management worldwide has been achieved using chemical fungicides, which may negatively affect human and animal health as well as the natural stasis of the soil native microbiota. This review provides an updated view of the new research conducted to understand and effectively manage the disease, based mainly on host plant resistance judicious use of fungicides together with other cultural practices such as crop rotation. Breeding for resistance remains challenging, but new SNPs markers for leaf spot diseases have been mapped and may be useful for improving host resistance which can reduce reliance on fungicides, especially after the ban of chlorothalonil in the E.U. Biocontrol using bacterial and fungal agents open new possibilities to reduce the use of chemical fungicides.

World Mycotoxin Journal, 2019

With 744 million metric tons produced in 2017/2018, bread wheat (Triticum aestivum) and durum whe... more With 744 million metric tons produced in 2017/2018, bread wheat (Triticum aestivum) and durum wheat (Triticum durum) are the second most widely produced cereal on a global basis. Prevention or control of wheat diseases may have an enormous impact on global food security and safety. Fusarium head blight is an economically debilitating disease of wheat that reduces the quantity and quality of grain harvested, and may lead to contamination with the mycotoxin deoxynivalenol, which affects the health of humans and domesticated animals. Current climate change scenarios predict an increase in the number of epidemics caused by this disease. Multiple strategies are available for managing the disease including cultural practices, planting less-susceptible cultivars, crop rotation, and chemical and biological controls. None of these strategies, however, is completely effective by itself, and an integrated approach incorporating multiple controls simultaneously is the only effective strategy to...

Journal of Applied Microbiology, 2018

Aim: to investigate the impact of inoculating peanut seeds with the biocontrol agent Trichoderma ... more Aim: to investigate the impact of inoculating peanut seeds with the biocontrol agent Trichoderma harzianum ITEM 3636 on the structure of bacterial and fungal communities from agricultural soils. Methods and Results: PCR-Denaturing gradient gel electrophoresis (PCR-DGGE) and next-generation sequencing (NGS) of amplicons (or marker gene amplification metagenomics) were performed to investigate potential changes in the structure of microbial communities from fields located in a peanut-producing area in the province of Córdoba, Argentina. Fields had history of peanut smut (caused by Thecaphora frezii) incidence. The Shannon indexes (H'), which estimate diversity, obtained from the PCR-DGGE assays did not show significant Accepted Article This article is protected by copyright. All rights reserved. differences neither for bacterial nor for fungal communities between control and inoculation treatments. On the other hand, the number of Operational Taxonomic Units (OTUs) obtained after NGS was similar between all the analyzed samples. Moreover, results of alpha and beta diversity showed that there were no significant variations between the relative abundances of the most representative bacterial and fungal phyla and genera, in both fields. Conclusions: T. harzianum ITEM 3636 decreases the incidence and severity of agriculturally relevant diseases without causing significant changes in the microbial communities of agricultural soils. Significance and Impact of the Study: our investigations provide information on the structure of bacterial and fungal communities in peanut-producing fields after inoculation of seeds with a biocontrol agent.