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

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.

Plant Disease ◽  
2005 ◽  
Vol 89 (3) ◽  
pp. 237-240 ◽  
Author(s):  
Matias Pasquali ◽  
Flavia Dematheis ◽  
Giovanna Gilardi ◽  
Maria Lodovica Gullino ◽  
Angelo Garibaldi

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.


1990 ◽  
Vol 68 (6) ◽  
pp. 1245-1248 ◽  
Author(s):  
D. J. Jacobson ◽  
T. R. Gordon

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.


1990 ◽  
Vol 68 (6) ◽  
pp. 1357-1363 ◽  
Author(s):  
R. C. Ploetz

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.


Agrikultura ◽  
2016 ◽  
Vol 27 (3) ◽  
Author(s):  
Sri Sri Hartati ◽  
Ummu Salamah Rustiani ◽  
Lindung Tri Puspasari ◽  
Wawan Kurniawan

ABSTRACTVegetatif compatibility of Fusarium oxysporum on various hostsMany strains or race of Fusarium oxysporum can be grouped based on compatibility reproduction from a variety of different strains called Vegetative Compatibility Group (VCG). This study was aimed to determine how the grouping of several isolates of F. oxysporum and grouping of several hosts of the fungus by vegetative compatibility group. Fusarium oxysporum isolated from chickpea plants that showed symptoms of fusarium wilt. The isolates of F. oxysporum of chili and tomatoes obtained from the culture collections of Mycology Laboratory of IPB. Stages of vegetative compatibility testing assayed through recovery of nit mutants, the identification of phenotype of nit mutant, and complementation test. There are 29 mutants isolated from the isolates of F. oxysporum. Nit1 mutant was obtained from all isolates of beans, tomatoes and peppers. NitM and Nit3 mutant isolates were obtained from chickpea 4 and chili sequentially. Two VCG and one single self compatibility (SSC) were assayed from isolates of F. oxysporum based on complementation testing.Keywords: Beans, Fusarium wilt, Nit mutant, SSC, VCGABSTRAKJamur Fusarium oxysporum memiliki banyak forma spesialis dan ras. Jamur ini dapat dikelompokkan berdasarkan kompatibilitas reproduksi dari berbagai strain yang berbeda disebut dengan vegetative compatibility group (VCG). Penelitian ini bertujuan untuk mengetahui cara pengelompokkan F. oxysporum dan pengelompokkan jamur tersebut dari beberapa inang berdasarkan kelompok kompatibilitas vegetatifnya. Isolasi F. oxysporum dilakukan dari tanaman kacang panjang yang menunjukkan gejala layu fusarium. Isolat F. oxysporum dari cabai dan tomat berasal dari koleksi Laboratorium Mikologi IPB. Tahapan pengujian kompatibilitas vegetatif melalui pembiakan nit mutan, identifikasi fenotipe nit mutan, dan pengujian komplementasi. Isolasi mutan F. oxysporum didapatkan 29 mutan. Mutan nit1 didapatkan dari semua isolat yang diperoleh dari semua inang yang berbeda yaitu kacang panjang, tomat dan cabai. Mutan nitM hanya didapatkan dari isolat kacang panjang 4 dan mutan nit3 hanya didapatkan dari isolat cabai. Berdasarkan uji komplementasi F. oxysporum yang diuji terdiri dari dua VCG dan satu single self compatibility (SSC).Kata Kunci: Kacang panjang, Layu fusarium, Nit mutant, SSC, VCG


1992 ◽  
Vol 32 (5) ◽  
pp. 651 ◽  
Author(s):  
MD Ramsey ◽  
RG O'Brien ◽  
KG Pegg

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.


Plant Disease ◽  
1998 ◽  
Vol 82 (5) ◽  
pp. 530-536 ◽  
Author(s):  
C. A. Clark ◽  
J-W. Hyun ◽  
M. W. Hoy

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.


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

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.


2001 ◽  
Vol 79 (7) ◽  
pp. 836-843 ◽  
Author(s):  
S I Mpofu ◽  
K Y Rashid

Following the discovery of substantial differences in the development and severity of Fusarium wilt in Linum usitatissimum L. (flax) wilt nurseries in western Canada, a study of the population structure of Fusarium oxysporum f.sp. lini (Bolley) Snyd. & Hans using vegetative compatibility analysis was initiated. Vegetative compatibility was determined using nitrate non-utilizing mutants. From a total of 105 isolates, 74 were assigned to 12 vegetative compatibility groups (VCG 0440-04411), 22 were not compatible with any other isolates and 9 did not produce mutants. The populations of F. oxysporum f.sp. lini in Fusarium wilt nurseries in western Canada were significantly different. There was a predominant VCG in each of the nurseries, which was either nonexistent or not common in other nurseries, VCG 0440 in Indian Head, 0441 in Treherne, 0442 in Morden-80, 0443 in Saskatoon, and 0444 in Morden-60. There were only three overlapping VCGs; VCG 0440 was common to Morden-60 and Indian Head and VCGs 0442 and 0444 were common to Morden-60 and Morden-80. The differences in disease development and severity observed previously may be due to the differences in the population structure of the pathogen. These findings have significant implications for the approaches to breeding for Fusarium wilt resistance in flax.Key words: Fusarium oxysporum f.sp. lini, flax, Fusarium wilt, genetic diversity, vegetative compatibility.


1991 ◽  
Vol 39 (2) ◽  
pp. 161 ◽  
Author(s):  
NY Moore ◽  
PA Hargreaves ◽  
KG Pegg ◽  
JAG Irwin

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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