Genetic relatedness of Brazilian Colletotrichum truncatum isolates assessed by vegetative compatibility groups and RAPD analysis

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.

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Characterisation of Australian isolates of Fusarium oxysporum f. sp. cubense by DNA fingerprinting analysis

Australian Journal of Agricultural Research ◽

10.1071/ar99172 ◽

2000 ◽

Vol 51 (8) ◽

pp. 945 ◽

Cited By ~ 15

Author(s):

K. S. Gerlach ◽

S. Bentley ◽

N. Y. Moore ◽

K. G. Pegg ◽

E. A. B. Aitken

Keyword(s):

Fusarium Oxysporum ◽

Dna Fingerprinting ◽

Genetic Relatedness ◽

Dna Amplification ◽

Vegetative Compatibility ◽

Dna Fingerprint ◽

Vegetative Compatibility Groups ◽

Fingerprinting Analysis ◽

Race 1 ◽

Race 2

Genetic variation among Australian isolates of the fungus Fusarium oxysporum f. sp. cubense (Foc), which causes Fusarium wilt in banana, was examined using DNA amplification fingerprinting (DAF). Ninety-four isolates which represented Races 1, 2, 3, and 4, and vegetative compatibility groups (VCGs) 0120, 0124, 0125, 0128, 0129, 01211, 01213/16, and 01220 were analysed. The genetic relatedness among isolates within each VCG, and between the 8 different VCGs of Foc present in Australia was determined. The DNA fingerprint patterns were VCG-specific, with each VCG representing a unique genotype. The genetic similarity among isolates within each VCG ranged from 97% to 100%. Among the different VCGs of Foc, 3 major clusters were distinguished which corresponded with race. All Race 1 and 2 isolates (VCGs 0124, 0125, 0128, and 01220) were closely related and clustered together, the Race 3 isolates from Heliconia clustered separately, and all Race 4 isolates (VCGs 0120, 0129, 01211, and 01213/16) clustered together. Fifteen isolates from Alstonville, NSW, were characterised because although they were classified as Race 2 based on their recovery from cooking banana cultivars, they belonged in VCG 0124, which had previously contained only Race 1 isolates. The occurrence of more than one race within a VCG means that vegetative compatibility grouping cannot be used to assign pathotype to pathogenic race as previously thought. It was possible to distinguish the Race 1 and Race 2 isolates within VCG 0124 using DNA fingerprinting, as each race produced a unique DNA fingerprint pattern. Among the Australian isolates, DNA fingerprinting analysis identified 9 different VCGs and genotypes of Foc.

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Evolutionary Relationships among the Fusarium oxysporum f. sp. cubense Vegetative Compatibility Groups

Applied and Environmental Microbiology ◽

10.1128/aem.00370-09 ◽

2009 ◽

Vol 75 (14) ◽

pp. 4770-4781 ◽

Cited By ~ 80

Author(s):

Gerda Fourie ◽

E. T. Steenkamp ◽

T. R. Gordon ◽

A. Viljoen

Keyword(s):

Fusarium Oxysporum ◽

Evolutionary History ◽

Genetic Relatedness ◽

Vegetative Compatibility ◽

Vascular Wilt ◽

Vegetative Compatibility Groups ◽

Formae Speciales ◽

History Of ◽

Fusarium Wilt Of Banana ◽

Banana Cultivar

ABSTRACT Fusarium oxysporum f. sp. cubense, the causal agent of fusarium wilt of banana (Musa spp.), is one of the most destructive strains of the vascular wilt fungus F. oxysporum. Genetic relatedness among and within vegetative compatibility groups (VCGs) of F. oxysporum f. sp. cubense was studied by sequencing two nuclear and two mitochondrial DNA regions in a collection of 70 F. oxysporum isolates that include representatives of 20 VCGs of F. oxysporum f. sp. cubense, other formae speciales, and nonpathogens. To determine the ability of F. oxysporum f. sp. cubense to sexually recombine, crosses were made between isolates of opposite mating types. Phylogenetic analysis separated the F. oxysporum isolates into two clades and eight lineages. Phylogenetic relationships between F. oxysporum f. sp. cubense and other formae speciales of F. oxysporum and the relationships among VCGs and races of F. oxysporum f. sp. cubense clearly showed that F. oxysporum f. sp. cubense's ability to cause disease on banana has emerged multiple times, independently, and that the ability to cause disease to a specific banana cultivar is also a polyphyletic trait. These analyses further suggest that both coevolution with the host and horizontal gene transfer may have played important roles in the evolutionary history of the pathogen. All examined isolates harbored one of the two mating-type idiomorphs, but never both, which suggests a heterothallic mating system should sexual reproduction occur. Although, no sexual structures were observed, some lineages of F. oxysporum f. sp. cubense harbored MAT-1 and MAT-2 isolates, suggesting a potential that these lineages have a sexual origin that might be more recent than initially anticipated.

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Strain Typing of Trichosporon asahii Clinical Isolates by Random Amplification of Polymorphic DNA (RAPD) Analysis

Journal of Laboratory Physicians ◽

10.1055/s-0041-1731111 ◽

2021 ◽

Author(s):

Thayanidhi Premamalini ◽

Vijayaraman Rajyoganandh ◽

Ramaraj Vijayakumar ◽

Hemanth Veena ◽

Anupma Jyoti Kindo ◽

...

Keyword(s):

Genetic Relatedness ◽

Rapd Analysis ◽

Clinical Isolates ◽

Clinical Samples ◽

Strain Typing ◽

Trichosporon Asahii ◽

Pcr Fingerprinting ◽

Specific Pcr ◽

Rapd Primer ◽

Random Amplification

Abstract Objective The aim of this study was to identify and isolate Trichosporon asahii (T. asahii) from clinical samples and to assess the genetic relatedness of the most frequently isolated strains of T. asahii using random amplification of polymorphic DNA (RAPD) primers GAC-1 and M13. Methods All the clinical samples that grew Trichosporon species, identified and confirmed by polymerase chain reaction (PCR) using Trichosporon genus-specific primers, were considered for the study. Confirmation of the species T. asahii was carried out by T. asahii-specific PCR. Fingerprinting of the most frequently isolated T. asahii isolates was carried out by RAPD using random primers GAC-1 and M13. Results Among the 72 clinical isolates of Trichosporon sp. confirmed by Trichosporon-specific PCR, 65 were found to be T. asahii as identified by T. asahii-specific PCR. Fingerprinting of the 65 isolates confirmed as T. asahii using GAC-1 RAPD primer yielded 11 different patterns, whereas that of M13 primer produced only 5 patterns. The pattern I was found to be the most predominant type (29.2%) followed by pattern III (16.9%) by GAC-1 primer. Conclusions This study being the first of its kind in India on strain typing of T. asahii isolates by adopting RAPD analysis throws light on genetic diversity among the T. asahii isolates from clinical samples. Fingerprinting by RAPD primer GAC-1 identified more heterogeneity among the T. asahii isolates than M13.

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Genetic Variability of Cercospora coffeicola from Organic and Conventional Coffee Plantings, Characterized by Vegetative Compatibility

Phytopathology ◽

10.1094/phyto-98-11-1205 ◽

2008 ◽

Vol 98 (11) ◽

pp. 1205-1211 ◽

Cited By ~ 6

Author(s):

R. B. Martins ◽

L. A. Maffia ◽

E. S. G. Mizubuti

Keyword(s):

Genetic Variability ◽

Production Systems ◽

Diversity Index ◽

Vegetative Compatibility ◽

Cercospora Leaf Spot ◽

Vegetative Compatibility Groups ◽

Nit Mutants ◽

Geographical Regions ◽

Minas Gerais State ◽

Cercospora Coffeicola

Cercospora leaf spot is a destructive fungal disease that has become a threat to the coffee industry in Brazil. Nevertheless, little is known about populations of its causal agent, Cercospora coffeicola. We evaluated the potential of using nitrogen-nonutilizing (nit) mutants and vegetative compatibility groups (VCGs) to characterize the genetic variability of the C. coffeicola population associated with coffee plantings in Minas Gerais state (MG), Brazil. A total of 90 monosporic isolates were obtained from samples collected according to a hierarchical sampling scheme: (i) state geographical regions (Sul, Mata, and Triângulo), and (ii) production systems (conventional and organic). Nit mutants were obtained and 28 VCGs were identified. The 10 largest VCGs included 72.31% of all isolates, whereas each of the remaining 18 VCGs included 1.54% of the isolates. Isolates of the largest VCGs were found in the three regions sampled. Based on the frequencies of VCGs at each sampled level, we estimated the Shannon diversity index, as well as its richness and evenness components. Genetic variability was high at all hierarchical levels, and a high number of VCGs was found in populations of C. coffeicola associated with both conventional and organic coffee plantings.

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