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

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.

1993 ◽  
Vol 33 (6) ◽  
pp. 797 ◽  
Author(s):  
NY Moore ◽  
KG Pegg ◽  
RN Allen ◽  
JAG Irwin

Isolates of Fusarium oxysporum f. sp. cubense from wilted banana plants in Queensland and New South Wales were characterised for vegetative compatibility. Six vegetative compatibility groups VCGs) were identified. Race 1 (VCGs 0124, 01241.5, 0125) was widespread, being detected in northern and southern Queensland as well as northern New South Wales. Race 2 (VCG 0128) was found attacking Bluggoe in North Queensland. Race 4 (VCGs 0120, 0129, 01211) was detected in Cavendish plantations in southern Queensland and in Lady finger plantations in New (South Wales and southern Queensland. Isolates of the race 4 VCG 0129 from Lady finger plantations were pathogenic to Cavendish cultivars in glasshouse tests.


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.


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.


2007 ◽  
Vol 97 (4) ◽  
pp. 461-469 ◽  
Author(s):  
X. G. Zhou ◽  
K. L. Everts

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.


1999 ◽  
Vol 89 (2) ◽  
pp. 156-160 ◽  
Author(s):  
Jurriaan J. Mes ◽  
Emma A. Weststeijn ◽  
Frits Herlaar ◽  
Joep J. M. Lambalk ◽  
Jelle Wijbrandi ◽  
...  

A collection of race 1 and race 2 isolates of Fusarium oxysporum f. sp. lycopersici was screened for vegetative compatibility and characterized by random amplified polymorphic DNA (RAPD) analysis to establish the identity and genetic diversity of the isolates. Comparison of RAPD profiles revealed two main groups that coincide with vegetative compatibility groups (VCGs). In addition, several single-member VCGs were identified that could not be grouped in one of the two main RAPD clusters. This suggests that F. oxysporum f. sp. lycopersici is a polyphyletic taxon. To assign avirulence genotypes to race 1 isolates, they were tested for their virulence on a small set of tomato lines (Lycopersicon esculentum), including line OT364. This line was selected because it shows resistance to race 2 isolates but, unlike most other race 2-resistant lines, susceptibility to race 1 isolates. To exclude the influence of other components than those related to the race-specific resistance response, we tested the virulence of race 1 isolates on a susceptible tomato that has become race 2 resistant by introduction of an I-2 transgene. The results show that both line OT364 and the transgenic line were significantly affected by four race 1 isolates, but not by seven other race 1 isolates nor by any race 2 isolates. This allowed a subdivision of race 1 isolates based on the presence or absence of an avirulence gene corresponding to the I-2 resistance gene. The data presented here support a gene-for-gene relationship for the interaction between F. oxysporum f. sp. lycopersici and its host tomato.


1990 ◽  
Vol 36 (5) ◽  
pp. 352-358 ◽  
Author(s):  
R. P. Larkin ◽  
D. L. Hopkins ◽  
F. N. Martin

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.


2000 ◽  
Vol 51 (8) ◽  
pp. 945 ◽  
Author(s):  
K. S. Gerlach ◽  
S. Bentley ◽  
N. Y. Moore ◽  
K. G. Pegg ◽  
E. A. B. Aitken

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.


Plant Disease ◽  
2000 ◽  
Vol 84 (7) ◽  
pp. 806-806 ◽  
Author(s):  
P. Di Primo ◽  
C. Cappelli

Fusarium corm rot of saffron (Crocus sativus L.), incited by Fusarium oxysporum Schlecht. f. sp. gladioli, causes severe stigma yield losses in L'Aquila Province in Central Italy. Primary symptoms during flowering (October through November) include basal stem rot, yellowing and wilting of shoots, and corm rot. The rapid spread of the disease is apparently caused only by movement of contaminated and/or infected corms (2,3). Ten isolates of F. oxysporum f. sp. gladioli, obtained from infected saffron crops located in the principal areas of saffron production in L'Aquila Province (2,3), were characterized by vegetative compatibility tests. The isolates were placed into vegetative compatibility groups (VCGs) using heterokaryon tests with chlorate-resistant nitrate-nonutilizing (nit) mutants. Based on complementation among these isolates and with a representative isolate of VCG 0340 (4), the tested isolates were assigned to VCG 0340. The fact that all isolates examined in this study belong to a single VCG supports the hypothesis that a clonal population of F. oxysporum f. sp. gladioli is spreading in L'Aquila Province in planting stock. In previous studies, only two Italian isolates of the pathogen obtained from Gladiolus were tested for vegetative compatibility, and both were included in VCG 0343 (1,4). Acquisition of further information on a larger number of isolates obtained from other cropping sites and associated with other hosts may result in a better understanding of the origin and spread of the pathogen in Italy, leading to improved strategies for control of Fusarium corm rot of saffron. References: (1) R. P. Baayen et al. Eur. J. Plant Pathol. 104:887, 1998. (2) C. Cappelli and G. Di Minco. Infitore Fitopatol. 49:27, 1999. (3) C. Cappelli and G. Di Minco. J. Plant Pathol. 80:253, 1998. (4) J. J. Mes et al. Plant Pathol. 43:362, 1994.


1990 ◽  
Vol 41 (5) ◽  
pp. 863 ◽  
Author(s):  
VM Brake ◽  
KG Pegg ◽  
JAG Irwin ◽  
PW Langdon

Wilt of bananas (Musa spp.), caused by Fusarium oxysporum Schlect. f. sp. cubense(E. F. Smith) Snyd. &Hans. (FOC), has a long history in subtropical Queensland, where it has destroyed many plantations of cv. Lady finger. Cavendish (AAA) clones are now being attacked in subtropical Queensland. Vegetative compatibility was used to subdivide Australian populations of FOC. One hundred and fortyeight isolates were placed in six vegetative compatibility groups (VCGs). VCG was correlated with virulence on specific cultivars in the field. All putative race 1 isolates belonged to VCGs 0124 and 0125 and with one exception, isolates in this group were recovered only from cultivars susceptible to race 1. Evidence is presented which suggests that wilt in Cavendish cultivars in Queensland is due to the previous widespread distribution of Cavendish competent strains (VCGS 0120,0129) in plantings of Lady finger, which is the major Australian race 1 susceptible cultivar.


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