The vegetative compatibility group to which the US biocontrol agent Aspergillus flavus AF36 belongs is also endemic to Mexico

2016 ◽  
Vol 120 (4) ◽  
pp. 986-998 ◽  
Author(s):  
A. Ortega-Beltran ◽  
L.C. Grubisha ◽  
K.A. Callicott ◽  
P.J. Cotty
Keyword(s):  
Aspergillus Flavus ◽  
Biocontrol Agent ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
The Us ◽  
Compatibility Group

scholarly journals Evaluation of the Atoxigenic Aspergillus flavus Strain AF36 in Pistachio Orchards

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 948-956 ◽  
Author(s):  
Mark A. Doster ◽  
Peter J. Cotty ◽  
Themis J. Michailides
Keyword(s):  
Aspergillus Flavus ◽  
Biocontrol Agent ◽  
Application Rate ◽  
Aflatoxin Contamination ◽  
Vegetative Compatibility Group ◽  
Wheat Seed ◽  
Soil Communities ◽  
Pistachio Nuts ◽  
Compatibility Group ◽  
Cotton Fields

The atoxigenic strain Aspergillus flavus AF36, which has been extensively used as a biocontrol agent in commercial corn and cotton fields to reduce aflatoxin contamination, was applied in research pistachio orchards from 2002 to 2005 and in commercial pistachio orchards from 2008 to 2011. AF36 was applied as hyphae-colonized steam-sterilized wheat seed (the same product and same application rate as used in cotton fields). In all orchards, applying the wheat-AF36 product substantially increased the proportion of vegetative compatibility group (VCG) YV36, the VCG to which AF36 belongs, within A. flavus soil communities. Application of the AF36 product in additional years further increased YV36 in the soil until it composed 93% of the A. flavus isolates in treated commercial orchards. Nonetheless, application of the AF36 product did not result in increased incidence of kernel decay of the nuts. For nuts harvested from commercial orchards, reductions in percentages of samples contaminated with aflatoxin from treated orchards (relative to that for untreated orchards) ranged from 20 to 45%, depending on the year. Because of the high value of pistachio nuts and the costs associated with rejection of shipments due to aflatoxin contamination, these reductions are significant and valuable to the pistachio industry.

scholarly journals Genetic Analysis of the Aspergillus flavus Vegetative Compatibility Group to Which a Biological Control Agent That Limits Aflatoxin Contamination in U.S. Crops Belongs

2015 ◽  
Vol 81 (17) ◽  
pp. 5889-5899 ◽  
Author(s):  
Lisa C. Grubisha ◽  
Peter J. Cotty
Keyword(s):  
Aspergillus Flavus ◽  
Mating Type ◽  
Biological Control Agent ◽  
Aflatoxin Contamination ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Time And Space ◽  
Type Locus ◽  
Content Type ◽  
Compatibility Group

ABSTRACTSome filamentous fungi inAspergillussectionFlaviproduce carcinogenic secondary compounds called aflatoxins. Aflatoxin contamination is routinely managed in commercial agriculture with strains ofAspergillus flavusthat do not produce aflatoxins. These non-aflatoxin-producing strains competitively exclude aflatoxin producers and reshape fungal communities so that strains with the aflatoxin-producing phenotype are less frequent. This study evaluated the genetic variation within naturally occurring atoxigenicA. flavusstrains from the endemic vegetative compatibility group (VCG) YV36. AF36 is a strain of VCG YV36 and was the first fungus used in agriculture for aflatoxin management. Genetic analyses based on mating-type loci, 21 microsatellite loci, and a single nucleotide polymorphism (SNP) in theaflCgene were applied to a set of 237 YV36 isolates collected from 1990 through 2005 from desert legumes and untreated fields and from fields previously treated with AF36 across the southern United States. One haplotype dominated across time and space. No recombination with strains belonging to VCGs other than YV36 was detected. All YV36 isolates carried the SNP inaflCthat prevents aflatoxin biosynthesis and themat1-2idiomorph at the mating-type locus. These results suggest that VCG YV36 has a clonal population structure maintained across both time and space. These results demonstrate the genetic stability of atoxigenic strains belonging to a broadly distributed endemic VCG in both untreated populations and populations where the short-term frequency of VCG YV36 has increased due to applications of a strain used to competitively exclude aflatoxin producers. This work supports the hypothesis that strains of this VCG are not involved in routine genetic exchange with aflatoxin-producing strains.

Vegetative compatibility and genetic diversity in the Aspergillus flavus population of a single field

1991 ◽  
Vol 69 (8) ◽  
pp. 1707-1711 ◽  
Author(s):  
Paul Bayman ◽  
Peter J. Cotty
Keyword(s):  
Aspergillus Flavus ◽  
Soil Samples ◽  
Vegetative Compatibility ◽  
Cotton Field ◽  
Test Field ◽  
Vegetative Compatibility Group ◽  
Vegetative Compatibility Groups ◽  
Compatibility Group ◽  
Single Field ◽  
Key Words Aspergillus

Aspergillus flavus was isolated from soil from a single Arizona cotton field in 1987, 1988, and 1989. Isolates from infected cotton bolls were collected from the same field in 1988. Isolates were assigned to vegetative compatibility groups via complementation tests between nitrate-nonutilizing mutants. Sixty-one of 105 isolates composed 13 vegetative compatibility groups; the remaining 44 isolates could not be assigned to groups. Forty-three isolates from other fields in Arizona composed 21 groups, 6 of which were also found in the test field. Distribution of vegetative compatibility groups in and outside the field was significantly different, based on a G-test. One vegetative compatibility group included 20% of all isolates from the test field, but was not found elsewhere. It was common in the test field in 1987 and 1988, but was not found in 1989. Boll and soil populations from 1988 were not significantly different. Single infected boll locules and 25-g soil samples often contained A. flavus individuals from more than one group. These results suggest that although many vegetative compatibility groups are widely distributed, a single field may have a unique population profile that changes significantly from year to year. Key words: Aspergillus flavus, vegetative compatibility, Nit−, imperfect fungi.

scholarly journals Characterization of Fusarium oxysporum Isolates Obtained from Cucumber in China by Pathogenicity, VCG, and RAPD

Plant Disease ◽  
2004 ◽  
Vol 88 (6) ◽  
pp. 645-649 ◽  
Author(s):  
D. J. Vakalounakis ◽  
Z. Wang ◽  
G. A. Fragkiadakis ◽  
G. N. Skaracis ◽  
D.-B. Li
Keyword(s):  
Fusarium Oxysporum ◽  
Random Amplified Polymorphic Dna ◽  
Vegetative Compatibility ◽  
Stem Rot ◽  
Chinese Isolate ◽  
Vegetative Compatibility Group ◽  
Group I ◽  
Compatibility Group ◽  
First Time

Thirty-four isolates of Fusarium oxysporum, obtained in China from cucumber plants showing either Fusarium wilt (F. oxysporum f. sp. cucumerinum) or root and stem rot (F. oxysporum f. sp. radicis-cucumerinum) symptoms, were characterized by pathogenicity, vegetative compatibility, and random amplified polymorphic DNA (RAPD). Of these, 23 isolates were identified by pathogenicity as F. oxysporum f. sp. cucumerinum, and one as F. oxysporum f. sp. radicis-cucumerinum, while 10 isolates were avirulent on cucumber, melon, sponge gourd, and pumpkin. The Chinese isolates of F. oxysporum f. sp. cucumerinum were assigned to RAPD groups III and XXI and to vegetative compatibility group (VCG) 0183, four new VCGs, 0184 to 0187, and a single-member VCG included in the artificial VCG 018-. The Chinese isolate of F. oxysporum f. sp. radicis-cucumerinum was assigned to RAPD group I and bridging VCG 0260/0261. The occurrence of F. oxysporum f. sp. radicis-cucumerinum on cucumber is reported for the first time in China.

scholarly journals Vegetative Compatibility Groups of Fusarium oxysporum f. sp. lactucae from Lettuce

Plant Disease ◽  
2005 ◽  
Vol 89 (3) ◽  
pp. 237-240 ◽  
Author(s):  
Matias Pasquali ◽  
Flavia Dematheis ◽  
Giovanna Gilardi ◽  
Maria Lodovica Gullino ◽  
Angelo Garibaldi
Keyword(s):  
Fusarium Oxysporum ◽  
Genetic Relatedness ◽  
The United States ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Vegetative Compatibility Groups ◽  
Compatibility Group ◽  
Race 1

Fusarium oxysporum f. sp. lactucae, the causal agent of Fusarium wilt of lettuce, has been reported in three continents in the last 10 years. Forty-seven isolates obtained from infected plants and seed in Italy, the United States, Japan, and Taiwan were evaluated for pathogenicity and vegetative compatibility. Chlorate-resistant, nitrate-nonutilizing mutants were used to determine genetic relatedness among isolates from different locations. Using the vegetative compatibility group (VCG) approach, all Italian and American isolates, type 2 Taiwanese isolates, and a Japanese race 1 were assigned to the major VCG 0300. Taiwanese isolates type 1 were assigned to VCG 0301. The hypothesis that propagules of Fusarium oxysporum f. sp. lactucae that caused epidemics on lettuce in 2001-02 in Italian fields might have spread via import and use of contaminated seeds is discussed.

Characterisation of Strains of Fusarium oxysporum f.sp. cubense by Production of Volatiles

1991 ◽  
Vol 39 (2) ◽  
pp. 161 ◽  
Author(s):  
NY Moore ◽  
PA Hargreaves ◽  
KG Pegg ◽  
JAG Irwin
Keyword(s):  
Fusarium Oxysporum ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Compatibility Group ◽  
Race 1 ◽  
Race 2 ◽  
Race 4

The production of volatiles on steamed rice by Australian isolates of Fusarium oxysporum f. sp. cubense correlated well with race and vegetative compatibility group (VCG). All race 4 isolates (VCGs 0120, 0129) produced distinctive volatile odours which gave characteristic gas chromatograms where the num- ber of peaks equated to VCG. Race 1 (VCGs 0124, 0125) and race 2 (VCG 0128) isolates, as well as non-pathogenic isolates of F. oxysporum from the banana rhizosphere, did not produce detectable volatiles and gave chromatograms without significant peaks.

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