scholarly journals Molecular and Vegetative Compatibility Groups Characterization of Aspergillus flavus Isolates from Kenya

2020 ◽  
Vol 6 (3) ◽  
pp. 231-250
Author(s):  
Alfred Mitema ◽  
◽  
Naser Aliye Feto ◽  
Keyword(s):  
Aspergillus Flavus ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Groups

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.

Characterization of a unique population of Fusarium oxysporum f.sp. cubense causing Fusarium wilt in Cavendish bananas at Carnarvon, Western Australia

1995 ◽  
Vol 46 (1) ◽  
pp. 167 ◽  
Author(s):  
KG Pegg ◽  
RG Shivas ◽  
NY Moore ◽  
S Bentley
Keyword(s):  
Fusarium Oxysporum ◽  
Vegetative Compatibility ◽  
Pcr Analysis ◽  
Banding Patterns ◽  
Vegetative Compatibility Groups ◽  
Rapd Pcr ◽  
Race 1 ◽  
Race 4 ◽  
Volatile Production

A unique population of Fusarium oxysporum f. sp. cubense affecting Cavendish cv. Williams banana plants was characterized using vegetative compatibility, volatile production, RAPD-PCR analysis, pectic enzyme production and pathogenicity. The isolates were more like race 1 isolates than race 4 isolates, although they were capable of attacking Cavendish clones. The Carnarvon isolates did not belong to any of the vegetative compatibility groups (VCGs) known to occur in Australia or overseas; they belonged in the 'inodoraturn' volatile group; they had 29% genetic similarity to race 4 isolates and 76% similarity to race 1 isolates based on RAPD-PCR banding patterns; they belonged in the same pectic zymogram group as race 1 isolates and were virulent on 3-month-old Cavendish cv. Williams, Gros Michel and Pisang Gajih Merah plants in glasshouse tests.

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 Characterization of Colletotrichum acutatum Causing Anthracnose of Anemone (Anemone coronaria L.)

2000 ◽  
Vol 66 (12) ◽  
pp. 5267-5272 ◽  
Author(s):  
Stanley Freeman ◽  
Ezra Shabi ◽  
Talma Katan
Keyword(s):  
Western Europe ◽  
Pcr Amplification ◽  
Vegetative Compatibility ◽  
Colletotrichum Acutatum ◽  
Vegetative Compatibility Groups ◽  
The Third ◽  
Artificial Inoculations ◽  
Species Specific ◽  
Arbitrarily Primed Pcr

ABSTRACT Anthracnose, or leaf-curl disease of anemone, caused byColletotrichum sp., has been reported to occur in Australia, western Europe, and Japan. Symptoms include tissue necrosis, corm rot, leaf crinkles, and characteristic spiral twisting of floral peduncles. Three epidemics of the disease have been recorded in Israel: in 1978, in 1990 to 1993, and in 1996 to 1998. We characterized 92Colletotrichum isolates associated with anthracnose of anemone (Anemone coronaria L.) for vegetative compatibility (72 isolates) and for molecular genotype (92 isolates) and virulence (4 isolates). Eighty-six of the isolates represented the three epidemics in Israel, one isolate was from Australia, and five isolates originated from western Europe. We divided these isolates into three vegetative-compatibility groups (VCGs). One VCG (ANE-A) included all 10 isolates from the first and second epidemics, and 13 of 62 examined isolates from the third epidemic in Israel, along with the isolate from Australia and 4 of 5 isolates from Europe. Another VCG (ANE-F) included most of the examined isolates (49 of the 62) from the third epidemic, as well as Colletotrichum acutatum from strawberry, in Israel. Based on PCR amplification with species-specific primers, all of the anemone isolates were identified as C. acutatum. Anemone and strawberry isolates of the two VCGs were genotypically similar and indistinguishable when compared by arbitrarily primed PCR of genomic DNA. Only isolate NL-12 from The Netherlands, confirmed as C. acutatum but not compatible with either VCG, had a distinct genotype; this isolate represents a third VCG of C. acutatum. Isolates from anemone and strawberry could infect both plant species in artificial inoculations. VCG ANE-F was recovered from natural infections of both anemone and strawberry, but VCG ANE-A was recovered only from anemone. This study of C. acutatum from anemone illustrates the potential of VCG analysis to reveal distinct subspecific groups within a pathogen population which appears to be genotypically homogeneous by molecular assays.

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.

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