scholarly journals Association of Mycotoxin and Sclerotia Production with Compatibility Groups in Aspergillus flavus from Peanut in Argentina

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 215-219 ◽  
Author(s):  
M. Victoria Novas ◽  
Daniel Cabral
Keyword(s):  
Aspergillus Flavus ◽  
Cyclopiazonic Acid ◽  
Vegetative Compatibility ◽  
Peanut Seed ◽  
Vegetative Compatibility Groups ◽  
Mycotoxin Production ◽  
Comparative Group

Vegetative compatibility (VC) of Aspergillus flavus isolates from peanut seed was studied to evaluate preliminary diversity and its association with mycotoxin production and sclerotia production and number. A. parasiticus isolates also were included as a comparative group. Isolates were divided into five categories based on mycotoxin production combination. Five of the A. flavus isolates were considered atypical because they simultaneously produced aflatoxins B, G, and cyclopiazonic acid (CPA). Vegetative compatibility groups (VCGs) were determined through complementation tests between nitrate-nonutilizing mutants. Sclerotia diameters and the number of sclerotia produced per square centimeter were determined for each isolate. Out of 32 isolates of A. flavus, 25 combined in 13 VCGs, whereas the remaining could not be assigned to any particular group. Each VCG included isolates of the same mycotoxin category, with only one exception. Also, all isolates within the same VCG were characterized by their ability to produce or not produce sclerotia. Isolates between VCGs showed significant differences in number of sclerotia per square centimeter, but differences in sclerotia size were not evident. Atypical isolates simultaneously producing aflatoxins B, G, and CPA formed a single and exclusive VCG.

Association of Morphology and Mycotoxin Production with Vegetative Compatibility Groups in Aspergillus flavus, A. parasiticus, and A. tamarii

Mycologia ◽  
1996 ◽  
Vol 88 (4) ◽  
pp. 574 ◽  
Author(s):  
B. W. Horn ◽  
R. L. Greene ◽  
V. S. Sobolev ◽  
J. W. Dorner ◽  
J. H. Powell ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Groups ◽  
Mycotoxin Production

Association of morphology and mycotoxin production with vegetative compatibility groups inAspergillus flavus, A. parasiticus, andA. tamarii

Mycologia ◽  
1996 ◽  
Vol 88 (4) ◽  
pp. 574-587 ◽  
Author(s):  
B. W. Horn ◽  
R. L. Greene ◽  
V. S. Sobolev ◽  
J. W. Dorner ◽  
J. H. Powell ◽  
...  
Keyword(s):  
Vegetative Compatibility ◽  
Vegetative Compatibility Groups ◽  
Mycotoxin Production

scholarly journals Variation in Competitive Ability Among Isolates of Aspergillus flavus from Different Vegetative Compatibility Groups During Maize Infection

2010 ◽  
Vol 100 (2) ◽  
pp. 150-159 ◽  
Author(s):  
H. L. Mehl ◽  
P. J. Cotty
Keyword(s):  
Aspergillus Flavus ◽  
Competitive Ability ◽  
Aflatoxin Contamination ◽  
Vegetative Compatibility ◽  
Life Strategy ◽  
Nucleotide Polymorphisms ◽  
Vegetative Compatibility Groups ◽  
Kernel Infection ◽  
Aflatoxin B ◽  
Maize Kernels

Aspergillus flavus, the primary causal agent of aflatoxin contamination, includes many genetically diverse vegetative compatibility groups (VCGs). Competitive ability during infection of living maize kernels was quantified for isolates from 38 VCGs. Kernels were inoculated with both a common VCG, CG136, and another VCG; after 7 days (31°C), conidia were washed from kernels, and aflatoxins and DNA were extracted from kernels and conidia separately. CG136-specific single-nucleotide polymorphisms were quantified by pyrosequencing; VCGs co-inoculated with CG136 produced 46 to 85 and 51 to 84% of A. flavus DNA from kernels and conidia, respectively. Co-inoculation with atoxigenic isolates reduced aflatoxin up to 90% and, in some cases, more than predicted by competitive exclusion alone. Conidia contained up to 42 ppm aflatoxin B1, indicating airborne conidia as potentially important sources of environmental exposure. Aflatoxin-producing potential and sporulation were negatively correlated. For some VCGs, sporulation during co-infection was greater than that predicted by kernel infection, suggesting that some VCGs increase dispersal while sacrificing competitive ability during host tissue colonization. The results indicate both life strategy and adaptive differences among A. flavus isolates and provide a basis for selection of biocontrol strains with improved competitive ability, sporulation, and aflatoxin reduction on target hosts.

scholarly journals DNA Fingerprinting Analysis of Vegetative Compatibility Groups in Aspergillus flavus from a Peanut Field in Georgia

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 254-258 ◽  
Author(s):  
C. E. McAlpin ◽  
D. T. Wicklow ◽  
B. W. Horn
Keyword(s):  
Aspergillus Flavus ◽  
Dna Probe ◽  
Vegetative Compatibility ◽  
Dna Fingerprint ◽  
Sample Population ◽  
Dna Fingerprints ◽  
Banding Patterns ◽  
Vegetative Compatibility Groups ◽  
Species Specific ◽  
Multiple Strains

The ability of species-specific DNA probe pAF28 to correctly match 75 strains of Aspergillus flavus isolated from a peanut field in Georgia with 1 of 44 distinct vegetative compatibility groupings (VCGs) was assessed. Multiple strains belonging to the same VCG typically produced identical DNA fingerprints, with the exception of VCG 17 and VCG 24, which contained strains that showed 83 and 87% similarity, respectively. A. flavus isolates sharing more than 80% of the fragments are recognized as belonging to the same DNA fingerprint group. Each VCG represented by a single isolate produced unique DNA fingerprints. The results provide further evidence that the pAF28 probe is able to distinguish A. flavus VCGs based on DNA fingerprints and can be used to predict the approximate number of VCGs in a sample population. The DNA probe also hybridized strongly and displayed multiple and distinct bands with other species in Aspergillus section Flavi: A. bombycis, A. caelatus, A. nomius, A. pseudotamarii, and A. tamarii. Although individual strains representing Aspergillus spp. in section Flavi produced DNA fingerprints with multiple bands, the banding patterns could not be used to classify these strains according to species.

scholarly journals Atoxigenic Aspergillus flavus Isolates Endemic to Almond, Fig, and Pistachio Orchards in California with Potential to Reduce Aflatoxin Contamination in these Crops

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 905-912 ◽  
Author(s):  
Alejandro Ortega-Beltran ◽  
Juan Moral ◽  
Adeline Picot ◽  
Ryan D. Puckett ◽  
Peter J. Cotty ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Climatic Changes ◽  
Aflatoxin Contamination ◽  
Vegetative Compatibility ◽  
Export Markets ◽  
Tree Crops ◽  
Vegetative Compatibility Groups ◽  
Single Genotype ◽  
Aflatoxin Accumulation

In California, aflatoxin contamination of almond, fig, and pistachio has become a serious problem in recent years due to long periods of drought and probably other climatic changes. The atoxigenic biocontrol product Aspergillus flavus AF36 has been registered for use to limit aflatoxin contamination of pistachio since 2012 and for use in almond and fig since 2017. New biocontrol technologies employ multiple atoxigenic genotypes because those provide greater benefits than using a single genotype. Almond, fig, and pistachio industries would benefit from a multi-strain biocontrol technology for use in these three crops. Several A. flavus vegetative compatibility groups (VCGs) associated with almond, fig, and pistachio composed exclusively of atoxigenic isolates, including the VCG to which AF36 belongs to, YV36, were previously characterized in California. Here, we report additional VCGs associated with either two or all three crops. Representative isolates of 12 atoxigenic VCGs significantly (P < 0.001) reduced (>80%) aflatoxin accumulation in almond and pistachio when challenged with highly toxigenic isolates of A. flavus and A. parasiticus under laboratory conditions. Isolates of the evaluated VCGs, including AF36, constitute valuable endemic, well-adapted, and efficient germplasm to design a multi-crop, multi-strain biocontrol strategy for use in tree crops in California. Availability of such a strategy would favor long-term atoxigenic A. flavus communities across the affected areas of California, and this would result in securing domestic and export markets for the nut crop and fig farmer industries and, most importantly, health benefits to consumers.

scholarly journals Frequent Shifts in Aspergillus flavus Populations Associated with Maize Production in Sonora, Mexico

2018 ◽  
Vol 108 (3) ◽  
pp. 412-420 ◽  
Author(s):  
A. Ortega-Beltran ◽  
P. J. Cotty
Keyword(s):  
Genetic Diversity ◽  
Aspergillus Flavus ◽  
Diversity Indices ◽  
Vegetative Compatibility ◽  
Low Frequencies ◽  
Maize Production ◽  
Vegetative Compatibility Groups

Aspergillus flavus frequently contaminates maize, a critical staple for billions of people, with aflatoxins. Diversity among A. flavus L morphotype populations associated with maize in Sonora, Mexico was assessed and, in total, 869 isolates from 83 fields were placed into 136 vegetative compatibility groups (VCGs) using nitrate-nonutilizing mutants. VCG diversity indices did not differ in four agroecosystems (AES) but diversity significantly differed among years. Frequencies of certain VCGs changed manyfold over single years in both multiple fields and multiple AES. Certain VCGs were highly frequent (>1%) in 2006 but frequencies declined repeatedly in each of the two subsequent years. Other VCGs that had low frequencies in 2006 increased in 2007 and subsequently declined. None of the VCGs were consistently associated with any AES. Fourteen VCGs were considered dominant in at least a single year. However, frequencies often varied significantly among years. Only 9% of VCGs were detected all 3 years whereas 66% were detected in only 1 year. Results suggest that the most realistic measurements of both genetic diversity and the frequency of A. flavus VCGs are obtained by sampling multiple locations in multiple years. Single-season sampling in many locations should not be substituted for sampling over multiple years.

Genetic diversity in Aspergillus flavus: association with aflatoxin production and morphology

1993 ◽  
Vol 71 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Paul Bayman ◽  
Peter J. Cotty
Keyword(s):  
Aspergillus Flavus ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Origin ◽  
Cladistic Analysis ◽  
Dna Amplification ◽  
Aflatoxin Production ◽  
Vegetative Compatibility ◽  
Dna Polymorphisms ◽  
Vegetative Compatibility Groups

Isolates of Aspergillus flavus belonging to at least 12 vegetative compatibility groups were characterized by aflatoxin production in vitro, morphology, and random amplified polymorphic DNAs. Aflatoxin B1 production differed significantly among vegetative compatibility groups; closely related isolates were similar intoxigenicity regardless of geographic origin. Cladistic analysis of DNA polymorphisms was consistent with vegetative compatibility data. A previously described dichotomy between S and L isolates of A. flavus based on morphology and physiology was strongly associated with both vegetative compatibility groups and DNA polymorphisms. All S isolates formed a single clade, apparently derived from the L group. Southern hybridizations of eight DNA amplification products showed that comigrating bands amplified by the same primer were always homologous within A. flavus but were not always homologous between A. flavus and closely related species. Results suggest that A. flavus is a species aggregate, that genotypes are dispersed over wide areas, and that aflatoxin production is more stable in nature than in culture. Key words: vegetative compatibility groups, random amplified polymorphic DNA, sclerotia, aflatoxin.

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