43 research outputs found
Growth rate and TRI5 gene expression profiles of Fusarium equiseti strains isolated from Spanish cereals cultivated on wheat and barley media at different environmental conditions
Fusarium equiseti
is a toxigenic species that often contaminates ce
real crops from diverse climatic regions such as
Northern and Southern Europe. Previous results suggested the existence of two distinct populations within this
species with differences in toxin pro
file which largely corresponded to North and South Europe (Spain). In this
work, growth rate profiles of 4
F. equiseti
strains isolated from different cereals and distinct Spanish regions were
determined on wheat and barley based media at a range of temperatures (15, 20, 25, 30, 35 and 40 °C) and water
potentialregimens(−0.7,−2.8,−7.0,and −9.8MPa,correspondingto
0.99,0.98,0.95 and 0.93aw values).Growth
was observed at all temperatures except at 40 °C, and at all the solute potential values except at−9.8 MPa when
combined with 15 °C. Optimal growth was observed at 20–
30 °C and −0.7/−2.8 MPa. The effect of these factors
on trichothecene biosynthesis was examined on a
F. equiseti
strain using a newly developed real time RT-PCR
protocol to quantify
TRI5
gene expression at 15, 25 and 35 °C and −0.7, −2.8, − 7.0 and −9.8 MPa on wheat
and barley based media. Induction of
TRI5
expression was detected between 25 and 35 °C and −0.7 and
− 2.8 MPa, with maximum values at 35 °C and −2.8 MPa being higher in barley than in wheat medium. These
results appeared to be consistent with a population well adapted to the present climatic conditions and predicted
scenarios for Southern Europe and suggested some differences depending on the cereal considered. These are also
discussed in relation to other
Fusarium
species co-occurring in cereals grown in this region and to their significance
for prediction and control strategies of toxigenic risk in future scenarios of climate change for this region
Divergence of the IGS rDNA in Fusarium proliferatum and Fusarium globosum reveals two strain specific non-orthologous types
A phylogenic analysis of Fusarium proliferatum
and closely related species was performed using the most
variable part within the intergenic spacer of the nuclear
ribosomal DNA (IGS) and compared with a previously
reported phylogeny performed in the same group of
samples with a partial region of the nuclear single copy
gene encoding the elongation factor 1α (EF-1α). The
phylogenies from both genomic sequences were not
concordant and revealed the presence of two nonorthologous
IGS types, named types I and II, in F.
proliferatum and Fusarium globosum.
Two specific PCR assays designed to amplify either IGS
type I or type II revealed that only one IGS type was
present in each individual in these two species. The
presence of both IGS types at the species level indicates
that homogenization has not been achieved yet. This might
be retarded if panmictic sexual reproduction was affected
by certain levels of clonal reproduction and/or by the
diverse hosts that these species are able to colonize. This
study indicates that taxonomic studies carried out with the
IGS rDNA, which has been widely used in Fusarium,
should be undertaken with caution
Mycoflora isolation and molecular characterization of Aspergillus and Fusarium species in Tunisian cereals
Wheat, barley and maize are the mainly consumed cereals in Tunisia. This study aimed to determine the mycoflora of these cereals with special focus on the mycotoxigenic Aspergillus and Fusarium species. Freshly harvested samples and other stored samples of each type of cereal (31 and 34 samples, respectively) were collected in Tunisia and cultured for fungal isolation and identification. Identification of fungal genera was based on morphological features. Aspergillus and Fusarium species were identified by species specific PCR assays complemented with DNA sequencing. Alternaria (70.83%), Eurotium (62.50%), Aspergillus (54.17%) and Penicillium (41.67%) were the most frequent fungi isolated from wheat. Penicillium (75%), Aspergillus (70%), Eurotium (65%) and Alternaria (65%) were the most frequently recovered genera from barley. The predominant genera in maize were Aspergillus(76.19%), Eurotium (42.86%), and Penicillium (38.09%). Aspergilllus, Penicillium, Fusarium and Alternaria were detected in both stored and freshly harvested grain samples. The frequencies of contamination with Aspergillus, Fusarium and Alternaria were higher in freshly harvested samples, whereas Penicillium species were more frequent in stored samples. The predominant Aspergillus species detected were A. flavus and A. niger. The Fusarium species detected were F. equiseti, F. verticillioides, F. nygamai, and F. oxysporum. This study suggested the potential risk for Aflatoxins and, to a lesser extent, for Ochratoxin A in Tunisian cereals. This is the first survey about mycoflora associated with wheat, barley and maize in Tunisia
Structure Variation And Dynamics of the Nuclear Ribosomal Intergenic Spacer Region in Key Gibberella Fujikuroi Complex Species
The intergenic spacer (IGS) region of the ribosomal DNA was cloned and sequenced in eight species within the
Gibberella fujikuroi
species complex with anamorphs in the genus
Fusarium
, a group that includes the most relevant toxigenic
species. DNA sequence analyses revealed two categories of repeated elements: long repeats and short repeats of 125 and 8 bp,
respectively. Long repeats were present in two copies and were conserved in all the species analyzed, whereas different numbers
of short repeat elements were observed, leading to species-specific IGS sequences with different length. In
Fusarium subglutinans
and
Fusarium nygamai
, these differences seemed to be the result of duplication and deletion events. Here, we propose a model
based on unequal crossing over that can explain these processes. The partial IGS sequence of 22
Fusarium proliferatum
isolates was
also obtained to study variation at the intraspecific level. The results revealed no differences in terms of number or pattern of
repeated elements and detected frequent gene conversion events. These results suggest that the homogenization observed at the
intraspecific level might not be achieved primarily by unequal crossing-over events but rather by processes associated with
recombination such as gene conversion events
Phylogenetic analyses and toxigenic profiles of Fusarium equiseti and Fusarium acuminatum isolated from cereals from Southern Europe
Fusarium equiseti and Fusarium acuminatum are toxigenic species that contaminate cereal crops from
diverse climatic regions. They are common in Spanish cereals. The information available on their
phylogenetics and toxigenic profiles is, however, insufficient to assist risk evaluation. In this work,
phylogenetic analyses were performed using partial sequences of the translation elongation factor gene
(EF-1a) of F. equiseti and F. acuminatum strains isolated from barley and wheat from Spain and other
countries. The Northern and Southern European F. equiseti strains largely separated into two phylogenetically
distinct clusters. This suggests the existence of two distinct populations within this species,
explaining its presence in these regions of markedly different climate. Production of type A and B
trichothecenes by the Spanish strains, examined in wheat cultures using a multitoxin analytical method,
indicated that F. equiseti could produce deoxynivalenol and nivalenol and other trichothecenes, at
concentrations that might represent a significant risk of toxin contamination for Southern European
cereals. F. acuminatum showed low intraspecific genetic variability and 58% of the strains could produce
deoxynivalenol at low level. Neither species was found to produce T-2 or HT-2 toxins. The present results
provide important phylogenetic and toxigenic information essential for the accurate prediction of
toxigenic risk
Microbiota asociada a la enfermedad de la punta negra del trigo duro. Efectos del riego, el abonado nitrogenado y la variedad cultivada en la incidencia de la enfermedad
La enfermedad fúngica de la punta negra del trigo se caracteriza por provocar en las semillas afectadas un oscurecimiento de la zona del embrión que en ocasiones puede extenderse hacia la hendidura central dejando el grano completamente ennegrecido. Su incidencia en el cultivo de trigo es extremadamente variable y depende en gran medida de las condiciones ambientales, así pues, condiciones de alta humedad pueden incrementar a punta negra. Su presencia en el trigo duro repercute en el rendimiento semolero. Además la pasta elaborada a partir de semilla enferma presenta manchas negras y adquiere color y olor desagradable. Esta enfermedad es poco conocida a nivel europeo, sin embargo existen numerosos estudios para conocer su etiología y los factores que afectan a su aparición en países como Nueva Zelanda, Australia, Estados Unidos o Canadá. El presente trabajo pretende dar a conocer esta patología en España, determinando la influencia del riego, el abonado nitrogenado y la variedad cultivada en la incidencia de la enfermedad. Para ello se ha contado con un diseño experimental basado en 10 cultivares sembrados en parcelas con dos tratamientos de riego y dos de abonado nitrogenado. El análisis de las semillas infectadas en cámara húmeda y medios de cultivo PDA y K reveló 12 géneros fúngicos diferentes, de los cuales Alternaria alternata y Fusarium proliferatum estaban presentes en todas las muestras. El estudio del riego y abonado nitrogenado mostró diferencias significativas en la incidencia de punta negra pero fueron los 10 cultivares incluidos en el ensayo los que mayor importancia cobraron desde el punto de vista de la aparición de la enfermedad. El genotipo resultó determinante a la hora de establecer los niveles de afectación ya que las muestras encuadradas botánicamente como Triticum turgidum subsp. Turgidum convar. Turgidum presentaron una mayor susceptibilidad. las prueas de patogenicidd con los tres principales hongos asociados a la punta negra dieron resultados negativos para la germinación-nascencia de las plántulas de trigo duro inoculadas
Fusarium proliferatum isolated from garlic in Spain: Identification, toxigenic potential and pathogenicity on related Allium species
Fusarium proliferatum has been reported on garlic in the Northwest USA, Spain and Serbia, causing
water-soaked tan-colored lesions on cloves. In this work, Fusarium proliferatum was isolated from 300 symptomatic
garlic bulbs. Morphological identification of Fusarium was confirmed using species-specific PCR assays and EF-1α
sequencing. Confirmation of pathogenicity was conducted with eighteen isolates. Six randomly selected F. proliferatum
isolates from garlic were tested for specific pathogenicity and screened for fusaric acid production. Additionally,
pathogenicity of each F. proliferatum isolate was tested on healthy seedlings of onion (Allium cepa), leek (A.
porrum), scallions (A. fistulosum), chives (A. schoenoprasum) and garlic (A. sativum). A disease severity index (DSI)
was calculated as the mean severity on three plants of each species with four test replicates. Symptoms on onion
and garlic plants were observed three weeks after inoculation. All isolates tested produced symptoms on all varieties
inoculated. Inoculation of F. proliferatum isolates from diseased garlic onto other Allium species provided new
information on host range and pathogenicity. The results demonstrated differences in susceptibility with respect
to host species and cultivar. The F. proliferatum isolates tested all produced fusaric acid (FA); correlations between
FA production and isolate pathogenicity are discussed. Additionally, all isolates showed the presence of the FUM1
gene suggesting the ability of Spanish isolates to produce fumonisins
Creación del primer Grupo iGEM (Competición Internacional de Biología Sintética) de Madrid: Facultad de Biología-UCM
En este Trabajo se describe la creación del primer Grupo iGEM de Madrid así como la elaboración de un biosensor que permite la detección de polen de olivo a tiempo real empleando metodos de ingeniería genética y robótica
Lifestyle in undergraduate students and demographically matched controls during the covid-19 pandemic in Spain
Few studies have used a multidimensional approach to describe lifestyle changes among undergraduate students during the COVID-19 pandemic or have included controls. This study aimed to evaluate lifestyle behaviors and mental health of undergraduate students and compare them with an age and sex-matched control group. A cross-sectional web survey using snowball sampling was conducted several months after the beginning of COVID-19 pandemic in Spain. A sample of 221 students was recruited. The main outcome was the total SMILE-C score. Students showed a better SMILE-C score than controls (79.8 +- 8.1 vs. 77.2 +- 8.3; p < 0.001), although these differences disappeared after controlling for covariates. While groups did not differ in the screenings of depression and alcohol abuse, students reported lower rates of anxiety (28.5% vs. 37.1%; p = 0.042). A lower number of cohabitants, poorer self-perceived health and positive screening for depression and anxiety, or for depression only were independently associated (p < 0.05) with unhealthier lifestyles in both groups. History of mental illness and financial difficulties were predictors of unhealthier lifestyles for students, whereas totally/moderate changes in substance abuse and stress management (p < 0.05) were predictors for the members of the control group. Several months after the pandemic, undergraduate students and other young adults had similar lifestyles
Zoología. Un modelo para la enseñanza no presencial
Memoria Proyecto de innovación nº 238 curso 2020/2