scholarly journals A Near-Isogenic Fusarium oxysporum f. sp. lycopersici Strain with a Novel Combination of Avirulence Characteristics

2003 ◽  
Vol 93 (11) ◽  
pp. 1360-1367 ◽  
Author(s):  
Hedwich A. S. Teunissen ◽  
Yvonne Boer ◽  
Jurgo Verkooijen ◽  
Ben J. C. Cornelissen ◽  
Michel A. Haring
Keyword(s):  
Fusarium Oxysporum ◽  
Length Polymorphism ◽  
Fragment Length Polymorphism ◽  
Aflp Marker ◽  
Genetic Change ◽  
Electrophoretic Karyotype ◽  
Race 1 ◽  
Tomato Cultivars ◽  
Race 2 ◽  
Isogenic Strains

A novel Fusarium oxysporum f. sp. lycopersici strain (F1-27) was obtained from protoplast fusions between race 1 Fol004 (putative avirulence genotype A1a2a3) and race 2 Fol007 (a1A2A3). Bioassays using different tomato cultivars revealed new virulence characteristics for F1-27 that were mitotically stable. The corresponding avirulence genotype for F1-27 was assigned a1A2a3. Despite their distinction in avirulence genotype, molecular analysis revealed that parent Fol007 and F1-27 were near-isogenic strains. The electrophoretic karyotype of F1-27 was identical to that observed for Fol007. Foxy-amplified fragment length polymorphism (AFLP) marker analysis showed that all Fol007-specific bands were present in F1-27. In addition, 11 new F1-27-specific Foxy insertions were identified. Segregation of both virulence and these new Foxy-AFLP markers was observed in a backcross between F1-27 and its parent Fol007. One marker was found to cosegregate with the a3 allele. The nature of the genetic change in this strain is discussed.

scholarly journals Multiple Evolutionary Trajectories Have Led to the Emergence of Races in Fusarium oxysporum f. sp. lycopersici

2016 ◽  
Vol 83 (4) ◽  
Author(s):  
V. Chellappan Biju ◽  
Like Fokkens ◽  
Petra M. Houterman ◽  
Martijn Rep ◽  
Ben J. C. Cornelissen
Keyword(s):  
Transposable Elements ◽  
Fusarium Oxysporum ◽  
Resistance Genes ◽  
Pcr Analysis ◽  
Genomic Fragment ◽  
Avirulence Genes ◽  
Content Type ◽  
Race 1 ◽  
Tomato Cultivars ◽  
Race 2

ABSTRACT Race 1 isolates of Fusarium oxysporum f. sp. lycopersici (FOL) are characterized by the presence of AVR1 in their genomes. The product of this gene, Avr1, triggers resistance in tomato cultivars carrying resistance gene I. In FOL race 2 and race 3 isolates, AVR1 is absent, and hence they are virulent on tomato cultivars carrying I. In this study, we analyzed an approximately 100-kb genomic fragment containing the AVR1 locus of FOL race 1 isolate 004 (FOL004) and compared it to the sequenced genome of FOL race 2 isolate 4287 (FOL4287). A genomic fragment of 31 kb containing AVR1 was found to be missing in FOL4287. Further analysis suggests that race 2 evolved from race 1 by deletion of this 31-kb fragment due to a recombination event between two transposable elements bordering the fragment. A worldwide collection of 71 FOL isolates representing races 1, 2, and 3, all known vegetative compatibility groups (VCGs), and five continents was subjected to PCR analysis of the AVR1 locus, including the two bordering transposable elements. Based on phylogenetic analysis using the EF1-α gene, five evolutionary lineages for FOL that correlate well with VCGs were identified. More importantly, we show that FOL races evolved in a stepwise manner within each VCG by the loss of function of avirulence genes in a number of alternative ways. IMPORTANCE Plant-pathogenic microorganisms frequently mutate to overcome disease resistance genes that have been introduced in crops. For the fungus Fusarium oxysporum f. sp. lycopersici, the causal agent of Fusarium wilt in tomato, we have identified the nature of the mutations that have led to the overcoming of the I and I-2 resistance genes in all five known clonal lineages, which include a newly discovered lineage. Five different deletion events, at least several of which are caused by recombination between transposable elements, have led to loss of AVR1 and overcoming of I. Two new events affecting AVR2 that led to overcoming of I-2 have been identified. We propose a reconstruction of the evolution of races in FOL, in which the same mutations in AVR2 and AVR3 have occurred in different lineages and the FOL pathogenicity chromosome has been transferred to new lineages several times.

scholarly journals Virulence and Molecular Genotyping Studies of Sporisorium reilianum Isolates in Sorghum

Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 523-529 ◽  
Author(s):  
Louis K. Prom ◽  
Ramasamy Perumal ◽  
Saradha R. Erattaimuthu ◽  
John E. Erpelding ◽  
Noe Montes ◽  
...  
Keyword(s):  
Fragment Length Polymorphism ◽  
South Texas ◽  
Pathogen Virulence ◽  
Inoculation Techniques ◽  
Sporisorium Reilianum ◽  
Race 1 ◽  
Race 2 ◽  
Small Clusters ◽  
Race 4 ◽  
Syringe Injection

Head smut, caused by the fungal pathogen Sporisorium reilianum, has been reported with increasing frequency in the grain sorghum growing areas of Texas. To facilitate analysis of changes in pathogen virulence, four inoculation techniques were examined: soil and teliospore mixture, seed coating, media placement, and syringe injection. Of the four, syringe injection was determined to be the most effective. Inoculations of sorghum host differentials BTx643, BTx7078, BTx635, SC170-6-17 (TAM2571), SA281 (Early Hegari), and Tx414 showed 23 of 32 Texas isolates were race 4. Two isolates from College Station, TX, were classified as race 1, but no race 2 or 3 isolates were found. New, virulent races 5 and 6 were identified among isolates from south Texas. Using 16 amplified fragment length polymorphism (AFLP) primer combinations, genetic diversity was assessed in DNA samples from 49 S. reilianum isolates, including 44 sorghum isolates from Texas, two from Uganda, and one from Mali; and two maize isolates from Mexico. Single-base extensions with EcoRI and MseI primers in the selective amplification increased the number of informative polymorphic bands. High genetic dissimilarity (50%) was observed between isolates originating from maize and those originating from sorghum. The resultant dendrogram, made using cluster analysis, grouped the Texas S. reilianum isolates into four small clusters with ≥82% similarity. Other than for two race 6 isolates from Weslaco, TX, no evidence for geographical or other restrictions on gene flow was evident.

scholarly journals Suppression of Fusarium Wilt Caused by Fusarium oxysporum f. sp. niveum Race 2 on Grafted Triploid Watermelon

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1326-1332 ◽  
Author(s):  
Anthony P. Keinath ◽  
Richard L. Hassell
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Disease Incidence ◽  
The United States ◽  
Infested Soil ◽  
Marketable Yield ◽  
Race 1 ◽  
Susceptible Control ◽  
Triploid Watermelon ◽  
Race 2

Fusarium wilt of watermelon, caused by the soilborne fungal pathogen Fusarium oxysporum f. sp. niveum race 2, is a serious, widespread disease present in major watermelon-growing regions of the United States and other countries. ‘Fascination,’ a high yielding triploid resistant to race 1, is grown in southeastern states in fields that contain a mixture of races 1 and 2. There is some benefit to using cultivars with race 1 resistance in such fields, even though Fascination is susceptible to Fusarium wilt caused by race 2. Experiments in 2012 and 2013 were done in fields infested primarily with race 2 and a mixture of races 1 and 2, respectively. Fascination was grafted onto four rootstock cultivars: bottle gourd (Lagenaria siceraria) ‘Macis’ and ‘Emphasis’ and interspecific hybrid squash (Cucurbita maxima× C. moschata) ‘Strong Tosa’ and ‘Carnivor.’ Nongrafted and self-grafted Fascination were used as susceptible control treatments. In both experiments, mean incidence of plants with symptoms of Fusarium wilt was ≥52% in the susceptible control treatments and ≤6% on the grafted rootstocks. Disease incidence did not differ between rootstock species or cultivars. In both years, Fascination grafted onto Strong Tosa and Macis produced more marketable-sized fruit than the susceptible control treatments. Grafted Emphasis and Carnivor also produced more fruit than the control treatments in 2012. The cucurbit rootstocks suppressed Fusarium wilt caused by race 2 and increased marketable yield of triploid watermelon grown in infested soil.

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.

scholarly journals Evolution of Virulence in Fusarium oxysporum f. sp. vasinfectum Using Serial Passage Assays Through Susceptible Cotton

2008 ◽  
Vol 98 (3) ◽  
pp. 296-303 ◽  
Author(s):  
B. Wang ◽  
C. L. Brubaker ◽  
W. Tate ◽  
M. J. Woods ◽  
J. J. Burdon
Keyword(s):  
Fusarium Oxysporum ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Rhizosphere Soil ◽  
Serial Passage ◽  
Clear Correlation ◽  
Spontaneous Mutations ◽  
Disease Symptoms ◽  
Evolution Of Virulence

Fifty strains of Fusarium oxysporum, recovered from rhizosphere soil around native Gossypium species and found to be mildly virulent on cotton (Gossypium hirsutum), were used to assay the propensity for evolution of virulence using serial passage assays through cotton. Only one lineage A strain, 2613, successfully completed 10 successive passages, while all others lost the ability to cause foliar disease symptoms at various stages during this process. Based on 46 amplified fragment length polymorphism (AFLP) markers generated with four EcoRI × MseI primer combinations, mutants were identified in offspring isolates from strain 2613 regardless of whether serial passages occurred in cotton or on water agar, suggesting the occurrence of spontaneous mutations. Significantly increased virulence was observed in the offspring isolates generated on cotton, while no increasing virulence was found in those obtained on water agar, suggesting that the evolution of virulence in F. oxysporum f. sp. vasinfectum is associated with the presence of cotton. No clear correlation was observed between the AFLP mutations and increased virulence in this study.

scholarly journals Biological and Molecular Characterization of Fusarium oxysporum f. sp. lycopersici Divides Race 1 Isolates into Separate Virulence Groups

1999 ◽  
Vol 89 (2) ◽  
pp. 156-160 ◽  
Author(s):  
Jurriaan J. Mes ◽  
Emma A. Weststeijn ◽  
Frits Herlaar ◽  
Joep J. M. Lambalk ◽  
Jelle Wijbrandi ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Random Amplified Polymorphic Dna ◽  
Vegetative Compatibility ◽  
Avirulence Gene ◽  
Resistance Response ◽  
Vegetative Compatibility Groups ◽  
Small Set ◽  
Race 1 ◽  
Race 2 ◽  
Susceptible Tomato

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.

scholarly journals Characterization of Pathogenic Races of Fusarium oxysporum f. sp. melonis Causing Fusarium Wilt of Melon in New York

Plant Disease ◽  
1997 ◽  
Vol 81 (6) ◽  
pp. 592-596 ◽  
Author(s):  
T. L. Zuniga ◽  
T. A. Zitter ◽  
T. R. Gordon ◽  
D. T. Schroeder ◽  
D. Okamoto
Keyword(s):  
New York ◽  
Fusarium Oxysporum ◽  
Nuclear Dna ◽  
New York State ◽  
Washington County ◽  
Length Polymorphisms ◽  
Close Relationship ◽  
Compatibility Group ◽  
Race 1 ◽  
Race 2

Forty-six isolates of Fusarium oxysporum f. sp. melonis obtained from soil samples throughout melon-producing areas in New York State were identified on the basis of pathogenicity and colony morphology. Physiological races 1 and 2 were identified by their reaction on a set of differential melon cultivars. Race 1 was widely distributed, occurring in six of the seven New York counties surveyed. Twenty-seven of the 28 race 1 isolates were associated with vegetative compatibility group (VCG) 0134, whereas one was incompatible with all known VCGs of F. oxysporum f. sp. melonis. Twelve out of 18 race 2 isolates were associated with VCG 0131, and occurred in four counties in eastern and western New York. Five isolates of race 2, associated with VCG 0130, were recovered from a farm in Washington County, as was a single race 2 isolate which was incompatible with all known VCGs of F. oxysporum f. sp. melonis. Restriction fragment length polymorphisms in the nuclear DNA revealed variability among the isolates examined, but race 1/VCG 0134 isolates from New York and Maryland were identical or nearly so, as were race 2/VCG 0131 isolates from the two states. These findings suggest a close relationship between the populations of F. oxysporum f. sp. melonis in New York and Maryland. Race 2 isolates were more virulent than race 1 isolates, based on the number of days to first symptoms and death of melon seedlings.

Sign in / Sign up

Export Citation Format

Share Document