Authors:C. Bolduan, J. Montes, B. Dhillon, V. Mirdita, and A. Melchinger
Ear rots of maize caused by
spp. reduce grain yield and produce mycotoxins, which are harmful to humans and animals. To breed maize cultivars resistant to
spp., reliable large-scale phenotyping is essential. Our objectives were to (i) examine the precision of the ELISA method for determination of important mycotoxins, namely deoxynivalenol (DON) and fumonisins (FUM), (ii) evaluate the potential of near-infrared reflectance spectroscopy (NIRS) to estimate concentrations of DON and FUM in grain produced in inoculated maize plants, and (iii) compare the efficiency of ELISA, NIRS, and visual rating of disease severity for estimation of mycotoxin concentrations. Insignificant variation was observed between duplicate evaluations of DON and FUM by ELISA, showing the high repeatability of this method. DON and FUM determinations by ELISA were more closely correlated with mycotoxin concentrations predicted through NIRS than with visual rating of disease severity. For the prediction of DON, NIRS had very high magnitude of the coefficients of determination of calibration and cross validation (R
= 0.90–0.88). Thus, NIRS has a promising potential to predict DON concentration in grain samples of inoculated maize genotypes evaluated in resistance breeding programs.
, M., Jestoi, M. and Rizzo, A. (2002): Controlling infection of cereal grain by toxigenic Fusariumspp. using fungal competitors. Proceedings of the 2002 Brighton Conference — Pests and Diseases, in press.
Authors:Andrea Rábai, Terézia Dula, and Laura Mugnai
Surveys were carried out in the 11 major wine regions of Hungary from 2003 to 2005 to identify pathogenic grapevine wood fungi. Occurrence of the disease in vineyards younger than 12 years, was studied separately. Sixty-six percent of the vineyards were free, thus symptoms of early decline were present in 34% of the plantations with 0,3–2,6% incidences. All vineyards over 12 years were affected by esca and early decline pathogens. Several fungi were consistently associated with these symptoms: The most frequently isolated species from older stocks were
Phaeomoniella chlamydospora, Phomopsis viticola, Botryosphaeria
. On younger, 2–4-year-old plants, mostly
Phaeomoniella chlamydospora, Phaeoacremonium
sp.occurred. Several associated species were identified on the declining stocks:
Alternaria alternata, Aspergillus
Numerous Fusarium species have been associated with the Fusarium head blight (FHB) disease of wheat, barley and other small-grain cereals, reducing worldwide cereal crop yields and, as a consequence of their mycotoxin production in the cereal grain, having an impact on both human and animal health.The year 2010 was extremely favourable for Fusarium head blight pathogens. Over a hundred symptomatic wheat heads were collected from various locations in Hungary. The aim was to determine the diversity of the Fusarium species infecting winter wheat ears. A total of 86 Fusarium spp. were morphologically identified from diseased kernels. F. sambucinum was found to be present in two of the Martonvásár samples. This pathogen had only previously been detected extremely sporadically. The species F. culmorum and F. verticillioides were found at a much lower rate than expected, while none of the isolates were identified as F. poae. On the basis of the results, 95% of the isolates belonged to the Fusarium graminearum species complex.
Authors:S. Dutta, A. Kundu, M. R. Chakraborty, S. Ojha, J. Chakrabarti, and N. C. Chatterjee
Siderophores are low molecular weight
(<1000 D) iron chelating compounds produced by microorganisms. Production of
siderophore is a device of antagonism as by virtue of the capacity of
siderophore production, a microorganism competes for Fe (III) with the others.
Production of siderophores by 9 different soil fungi and wood-decay fungi was
studied following CAS - assay and CAS - agar plate assay. Optimization for the production of
siderophores was done by varying the levels of pH and Fe (III) concentrations
in the low nutrient medium. All the test fungi could produce siderophores,
though the degree of production recorded to be very low both in Botryodiplodia
theobromae and in Fusarium spp. On the other hand, all the species of
Trichoderma showed their excellency in siderophore production. The optimum pH
for production of siderophores remained at neutral pH level though the range
varied from pH 6.0-8.0. The optimum range of the
concentration of Fe (III) required for siderophore production was recorded to
be 1.5-21.0 µM. However, the stress condition of
iron might be a decisive factor for siderophore production.
Authors:Tünde Pusztahelyi, L. Radócz, Cs. Gellért, Szilvia Kovács, Zsuzsanna Szabó, I. Pócsi, and A. Vad
There are extensive data on effects of antifungal agents on the plant pathogens, especially on Fusariums spp. species. However, investigations on the interaction of chemicals and the treated cultivars are rare. The aim of the study was to test two types of fungicide mixtures, azoxystrobin-propiconazole, and prothioconazole-tebuconazole, which are applied in wheat cultivars intensively, on six fodder maize hybrids that were infected with Fusarium proliferatum in the R1 growth stage in a field trial. The effect of the fungicide treatment was tested on the starch content and antifungal, antioxidant polyphenols of the kernels in the R3–R4 and R6 stage of the cultivars. The level of the fungal presence and the fumonisin concentration of the kernels were increased significantly under the artificial infection. The fumonisin concentration was variable at the R6 stage of the hybrid maize kernels. The treatment with prothioconazole and tebuconazole was found to be suitable when it was done before flowering, while the azoxystrobin-propiconazole treatments were equally successful before and after maize flowering considering the decreasing fumonisin concentration of the kernels. Both fungicide mixtures, when they were applied after maize flowering, affected the starch biosynthesis to the R3–R4 stage significantly. Meanwhile, azoxystrobin-propiconazole also significantly affected the antioxidant flavone/flavanol contents from the R3–R4 stage to the R6 stage.
Adame-García, J., Trigos-Landa, A. R., Iglesias-Andreu, L. G., Flores-Estevez, N. and Luna-Rodríguez, M. (2011): Isozymic and pathogenic variations of Fusariumspp. associated with vanilla stem and root rotting