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.

scholarly journals Characterization of a Regional Population of Fusarium oxysporum f. sp. niveum by Race, Cross Pathogenicity, and Vegetative Compatibility

2007 ◽  
Vol 97 (4) ◽  
pp. 461-469 ◽  
Author(s):  
X. G. Zhou ◽  
K. L. Everts
Keyword(s):  
Fusarium Oxysporum ◽  
Vegetative Compatibility ◽  
Infested Soil ◽  
Vegetative Compatibility Group ◽  
Atlantic Region ◽  
Compatibility Group ◽  
Race 1 ◽  
Regional Population ◽  
Race 2

Eighty-eight isolates of Fusarium oxysporum f. sp. niveum, collected from wilted watermelon plants and infested soil in Maryland and Dela-ware, were characterized by cross pathogenicity to muskmelon, race, and vegetative compatibility. Four isolates (4.5%) were moderately pathogenic to ≥2 of 18 muskmelon cultivars in a greenhouse test, and one representative isolate also was slightly pathogenic in field microplots. The four isolates all were designated as race 2, and were in vegetative compatibility group (VCG) 0082. Of the 74 isolates to which a VCG could be assigned, 41 were in VCG 0080, the VCG distributed most widely; 27 were in VCG 0082, and were distributed in half of the 20 watermelon fields surveyed; and 6 were in the newly described VCG 0083, and were restricted to three fields. Among the isolates in VCG 0080, 8 were designated as race 0, 21 as race 1, and 12 as race 2. Of the isolates in VCG 0082, 6 were designated as race 0, 11 as race 1, and 10 as race 2. All isolates in VCG 0083 were designated as race 2. Isolates from more than one race within the same VCG or isolates from more than one VCG were recovered from single plants and fields. No differences in aggressiveness on differential watermelon cultivars were observed among isolates from different VCGs of the same race. A diverse association between virulence and VCG throughout the Mid-Atlantic region suggests that the pathotypes of F. oxysporum f. sp. niveum may be of local origin or at least long existent in the region.

Further investigations of vegetative compatibility within Fusarium oxysporum f.sp. melonis

1990 ◽  
Vol 68 (6) ◽  
pp. 1245-1248 ◽  
Author(s):  
D. J. Jacobson ◽  
T. R. Gordon
Keyword(s):  
Genetic Diversity ◽  
North America ◽  
Fusarium Oxysporum ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Culture Collections ◽  
Vegetative Compatibility Groups ◽  
The Third ◽  
Geographic Origins ◽  
Compatibility Group

One hundred and nineteen strains of Fusarium oxysporum f.sp. melonis were characterized by virulence and vegetative compatibility. One hundred and seven strains were placed in four previously reported vegetative compatibility groups: 0130, 0131, 0133, and 0134. Four strains were placed in three new vegetative compatibility groups, and the remaining eight strains were vegetatively self-incompatible. Two of the three new vegetative compatibility groups shared similar geographic origins and distribution with two previously reported vegetative compatibility groups; the third represented a more isolated infestation. All vegetatively self-incompatible isolates originated from culture collections; none have been recently isolated from nature. These newly characterized strains extend our knowledge of genetic diversity in F. oxysporum f.sp. melonis. All four F. oxysporum f.sp. melonis races exist in more than one vegetative compatibility group. European strains represent four vegetative compatibility groups, one of which is present in North America and another in the Middle East. The significance of this diversity is unknown, as are the phylogenetic relationships among strains in this forma specialis.

scholarly journals Race Determination and Vegetative Compatibility Grouping of Fusarium oxysporum f. sp. melonis from South Africa

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 231-234 ◽  
Author(s):  
W. Schreuder ◽  
S. C. Lamprecht ◽  
G. Holz
Keyword(s):  
South Africa ◽  
Fusarium Oxysporum ◽  
South African ◽  
Geographic Region ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Compatibility Group ◽  
Race 1 ◽  
Race 2 ◽  
High Degree

Isolates of Fusarium oxysporum f. sp. melonis (72 total) obtained from 30 fields in 17 melonproducing regions in South Africa were race typed, using differential cvs. CM 17187, Doublon, Perlita, and Topmark, and grouped on the basis of vegetative compatibility. Fifty-four isolates were identified as race 0, eight as race 1, and ten as race 2. Race 0 occurred in 15 of 17 regions, whereas race 1 was sporadically recovered. Race 2 was obtained from only four fields located in one geographic region. Perlita plants (carrying the gene Fom3) inoculated with local isolates of races 0 and 2 and reference isolates of race 0 became stunted, and their leaves became yellow, thickened, and brittle. Using two inoculation methods, similar symptoms were induced by reference and local isolates of race 0 on Perlita seedlings. The results indicated that Fom3 in Perlita confers a tolerant reaction compared with the resistant reaction of gene Fom1 in Doublon and, therefore, should not be used alone in race determination tests. All isolates belonged to vegetative compatibility group 0134, indicating a high degree of genetic homogeneity among the South African F. oxysporum f. sp. melonis population.

Vegetative compatibility within Fusarium oxysporum f.sp. niveum and its relationship to virulence, aggressiveness, and race

1990 ◽  
Vol 36 (5) ◽  
pp. 352-358 ◽  
Author(s):  
R. P. Larkin ◽  
D. L. Hopkins ◽  
F. N. Martin
Keyword(s):  
Fusarium Oxysporum ◽  
The United States ◽  
Soil Samples ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Groups ◽  
Nit Mutants ◽  
The World ◽  
Infested Field ◽  
Race 1 ◽  
Race 2

Over 250 isolates of Fusarium oxysporum collected from infected watermelon plants and soil samples from a pathogen-infested field, as well as known isolates of F. oxysporum f. sp. niveum imported from various locations around the world, were tested for pathogenicity on watermelon and used to determine vegetative compatibility groups (VCGs) within F. oxysporum f. sp. niveum. Vegetative compatibility was assessed on the basis of heterokaryon formation among nitrate-nonutilizing mutants. Race determinations were made by screening isolates on six different watermelon cultivars of varying resistance. All isolates of F. oxysporum f. sp. niveum belonged to one of three distinct VCGs, and were incompatible with isolates that were not pathogenic on watermelon. Isolates of F. oxysporum f. sp. niveum were subdivided into two races and there was a direct relationship between VCG and race. VCG 0080 consisted of race 1 isolates from five states of the United States, Taiwan, and Australia. VCG 0081 consisted solely of race 1 isolates from Florida. VCG 0082 was comprised solely of race 2 isolates, all of which were capable of causing severe wilt on all cultivars tested. Numerous Florida isolates were compatible with race 2 isolates from Texas and demonstrated comparable virulence on all cultivars, confirming the presence of race 2 in Florida. With F. oxysporum f. sp. niveum, vegetative compatibility can be utilized as an alternative or collaborative method to distinguish pathogenic from nonpathogenic strains of F. oxysporum and to differentiate subforma specialis virulence characteristics. Key words: fusarium wilt, nit mutants, watermelon.

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

2000 ◽  
Vol 51 (8) ◽  
pp. 945 ◽  
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.

Variability in Fusarium oxysporum f.sp. cubense

1990 ◽  
Vol 68 (6) ◽  
pp. 1357-1363 ◽  
Author(s):  
R. C. Ploetz
Keyword(s):  
Fusarium Oxysporum ◽  
Population Biology ◽  
Potato Dextrose Agar ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Panama Disease ◽  
Vegetative Compatibility Groups ◽  
Nit Mutants ◽  
Compatibility Group ◽  
Time Required

A worldwide collection of 96 isolates of Fusarium oxysporum f.sp. cubense (incitant of fusarial wilt of banana or Panama disease) from 12 countries was used to assess population structure in the pathogen; isolates were diverse for vegetative compatibility (11 vegetative compatibility groups) and race-specific virulence (races 1, 2, and 4). Rates of radial growth on potato dextrose agar differed at temperatures ranging from 8–36 °C for isolates in different VCGs and races (P < 0.05). On a KClO3-amended medium used to generate nitrate-nonutilizing (nit) mutants, variability in chlorate (a toxic analog of nitrate) sensitivity and the time required before nit mutants arose on the medium (mutability) was related primarily to vegetative compatibility group. In addition, cultural morphology on modified Komada's medium and potato dextrose agar was related primarily to vegetative compatibility group, whereas race was not as consistently related to these traits. In studies on the population biology and diversity in F. oxysporum f.sp. cubense, vegetative compatibility was a more useful character than race. On the basis of these results, it is suggested that F. oxysporum f.sp. cubense has had diverse origins.

Variation within and between populations of Fusarium oxysporum based on vegetative compatibility and mitochondrial DNA

1992 ◽  
Vol 70 (6) ◽  
pp. 1211-1217 ◽  
Author(s):  
T. R. Gordon ◽  
D. Okamoto
Keyword(s):  
Mitochondrial Dna ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Agricultural Field ◽  
Vegetative Compatibility Groups ◽  
Field Soils ◽  
Compatibility Group ◽  
Mitochondrial Dna Haplotype

Two hundred isolates of Fusarium oxysporum, 100 from each of two different locations, were collected from agricultural field soils in the San Joaquin Valley of California. These isolates comprised 39 different vegetative compatibility groups. Based on the frequency distribution of vegetative compatibility groups, populations of F. oxysporum at the two collection sites were different. At least one isolate from each vegetative compatibility group was examined for polymorphisms in mitochondrial DNA. A total of 41 differences in mitochondrial DNA were identified, each of which was treated as a character and scored as present or absent in each strain. There were 11 unique combinations (haplotypes) of the 41 characters. Three mitochondrial DNA haplotypes were common to both sites and the remaining eight occurred at only one of the two sites. Isolates in the same vegetative compatibility group were always associated with the same mitochondrial DNA haplotype. Many isolates in different vegetative compatibility groups also shared a common mitochondrial DNA haplotype. Fusarium oxysporum f.sp. melonis, cause of Fusarium wilt of muskmelon, was associated with the same mitochondrial DNA haplotype as eight vegetative compatibility groups of F. oxysporum that were not pathogenic to muskmelon. This result may indicate that either the pathogen was a recent derivative of nonpathogenic strains at the same location or avirulent strains have been derived from the pathogen. Key words: anastomosis, fungi, heterokaryon, Fusarium wilt.

Fusarium oxysporum associated with wilt and root rot of tomato in Queensland; races and vegetative compatibility groups

1992 ◽  
Vol 32 (5) ◽  
pp. 651 ◽  
Author(s):  
MD Ramsey ◽  
RG O'Brien ◽  
KG Pegg
Keyword(s):  
Fusarium Oxysporum ◽  
Root Rot ◽  
Vascular Tissue ◽  
Group Analysis ◽  
Vegetative Compatibility ◽  
Crown Rot ◽  
Vegetative Compatibility Group ◽  
Vegetative Compatibility Groups ◽  
Compatibility Group ◽  
Pathogenicity Tests

Twenty-two isolates of Fusarium oxysporum, from Queensland's major tomato growing areas, were studied in glasshouse pathogenicity tests and assessed for vegetative compatibility. Isolates of Fusarium oxysporum f. sp. lycopersici were identified to race using pathogenicity tests with 4 differential tomato cultivars: Grosse Lisse, Scorpio, moradade and Delta Tristar. The occurrence of race 3 in the Bundaberg district in 1988 was established. In glasshouse experiments, Fusarium wilt severity was influenced by inoculum concentration (1 x 106 v. 5 x 106 conidia/ml). Pathogenic and non-pathogenic isolates were distinguished by vegetative compatibility group analysis. However, all races were in a single vegetative compatibility group and could not be differentiated using this technique. Isolates collected from discoloured vascular tissue in the lower stems of plants with severe root rot (Pythium spp. associated), were non-pathogenic to tomato, bean and pea, although some isolates caused slight damage to cucumber. These isolates were distinctly different from Fusarium oxysporum f. sp. radicis-lycopersici, the cause of root and crown rot.

scholarly journals Relationships Among Wilt-Inducing Isolates of Fusarium oxysporum from Sweetpotato and Tobacco

Plant Disease ◽  
1998 ◽  
Vol 82 (5) ◽  
pp. 530-536 ◽  
Author(s):  
C. A. Clark ◽  
J-W. Hyun ◽  
M. W. Hoy
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Random Amplified Polymorphic Dna ◽  
Severe Disease ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Burley Tobacco ◽  
Compatibility Group ◽  
Race 1 ◽  
New Race

Thirty-five isolates of Fusarium oxysporum obtained from diseased sweetpotato or tobacco were compared for pathogenicity on two cultivars each of sweetpotato and tobacco, by random amplified polymorphic DNA (RAPD) profiles, and by vegetative compatibility group (VCG) analysis. Analysis of RAPD profiles revealed five clusters of isolates that corresponded to patterns of pathogenicity. One cluster of isolates, designated as F. oxysporum f. sp. nicotianae, induced severe wilting on both tobacco cultivars but varied from weakly to highly aggressive on the sweetpotato cultivars. Four of the 16 isolates from this group were originally isolated from sweetpotato, and 1 isolate caused severe disease on both crops. Three clusters included isolates from sweetpotato that were virulent on Porto Rico, caused little or no disease on Beauregard and burley tobacco (cv. Kentucky 5), and did not cause wilt on flue-cured tobacco (cv. Gold Dollar). These isolates were designated as race 0 of F. oxysporum f. sp. batatas. Isolates obtained from sweetpotato from California clustered separately from other sweetpotato isolates and the tobacco isolates. They differed from other sweetpotato isolates in being virulent on Beauregard and are proposed as a new race 1 of F. oxysporum f. sp. batatas. VCG analysis was of limited value with the isolates in this study because many isolates were self-incompatible. In each case, all members of a VCG fell within the same cluster defined by RAPDs. This study demonstrated that F. oxysporum from at least three genetically distinct lineages can cause Fusarium wilt on sweetpotato, and that the host ranges of F. oxysporum f. sp. batatas and F. oxysporum f. sp. nicotianae overlap and include plants from two different families.

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