scholarly journals Genetic Diversity of Fusarium oxysporum f. sp. dianthi in Southern Spain

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Raúl Castaño ◽  
Barbara Scherm ◽  
Manuel Avilés
Keyword(s):  
Fusarium Oxysporum ◽  
Phylogenetic Analyses ◽  
Gene Sequencing ◽  
Southern Spain ◽  
Specific Pcr ◽  
Rapd Pcr ◽  
Race 1 ◽  
Pathogenicity Tests ◽  
Specific Band ◽  
Race 2

The diversity of races and prevalence of pathogenic populations of Fusarium oxysporum f. sp. dianthi (Fod) were surveyed in an area in southern Spain. From 54 farms, 132 isolates were collected from wilted carnation plants. Isolates were characterized by RAPD-PCR, DNA sequence analysis of the TEF1-α gene, and race-specific molecular markers. Selected isolates from RAPD groups were phenotypically evaluated by pathogenicity tests. Data analysis showed that Fod race 2 was the most frequent and prevalent race in the study area, followed by race 1/8. Moreover, phylogenetic analyses showed similar results, which were different to those of the race-specific PCR assays. It was concluded that (i) seven isolates were not classified in groups where Fod testers were clustered; even they showed different results when race-specific markers were used, (ii) ten isolates with retarded race 1 or race 8 specific band were characterized as F. proliferatum by TEF1-α gene sequencing and clustered into an outgroup, and (iii) six isolates failed to generate an amplification signal using race-specific markers. Furthermore, three of them were grouped close to race 2 tester according to the phylogenetic analyses, showing the same differential pathogenicity as race 2. This may indicate a Fod race 2 subgroup in this region.

Comparing vegetative compatibility and protein banding patterns for identification of Fusarium oxysporum f.sp. apii race 2

1991 ◽  
Vol 37 (9) ◽  
pp. 669-674 ◽  
Author(s):  
K. F. Toth ◽  
M. L. Lacy
Keyword(s):  
Fusarium Oxysporum ◽  
Polyacrylamide Gel Electrophoresis ◽  
Vegetative Compatibility ◽  
Wild Type ◽  
Banding Patterns ◽  
Formae Speciales ◽  
Compatibility Group ◽  
Race 1 ◽  
Pathogenicity Tests ◽  
Race 2

Vegetative compatibility grouping and electrophoretic separation of total proteins were compared as possible techniques for identifying isolates of Fusarium oxysporum f.sp. apii race 2, the cause of fusarium yellows of celery. Vegetative compatibility grouping was determined by pairing chlorate-tolerant, nitrate-nonutilizing mutants on a minimal medium containing nitrate as the sole nitrogen source. Heterokaryon formation, which resulted in wild-type growth, occurred only between mutants from vegetatively compatible isolates. All isolates of F. oxysporum f.sp. apii race 2 examined were placed within a unique vegetative compatibility group that excluded F. oxysporum f.sp. apii race 1 and the 11 other formae speciales of F. oxysporum tested. Few differences were observed in protein banding patterns among isolates of F. oxysporum f.sp. apii race 2, F. oxysporum f.sp. apii race 1, 11 other formae speciales of F. oxysporum, and 2 formae speciales of F. solani on 12% polyacrylamide gels. No banding pattern unique to F. oxysporum f.sp. apii race 2 was observed. Vegetative compatibility grouping could be accomplished more rapidly than greenhouse pathogenicity tests and more accurately identified race 2 isolates in a population of isolates of F. oxysporum from muck soils than did greenhouse pathogenicity tests or electrophoretic protein banding patterns. Key words: celery, fusarium yellows, nitrate-nonutilizing mutants, polyacrylamide gel electrophoresis.

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 Host Range of Verticillium isaacii and Verticillium klebahnii from Artichoke, Spinach, and Lettuce

Plant Disease ◽  
2015 ◽  
Vol 99 (7) ◽  
pp. 933-938 ◽  
Author(s):  
Suraj Gurung ◽  
Dylan P. G. Short ◽  
Xiaoping Hu ◽  
German V. Sandoya ◽  
Ryan J. Hayes ◽  
...  
Keyword(s):  
New Species ◽  
Host Range ◽  
Disease Severity ◽  
Verticillium Wilt ◽  
Agricultural Soils ◽  
Phylogenetic Analyses ◽  
Greenhouse Experiment ◽  
Vascular Wilt ◽  
Race 1 ◽  
Race 2

Verticillium is a genus that includes major vascular wilt pathogens. Recently, multilocus phylogenetic analyses of the genus identified five new species, including Verticillium isaacii and V. klebahnii, both of which occur in agricultural soils in coastal California and have been isolated from asymptomatic and diseased spinach and lettuce plants. Little data are available regarding their pathogenicity and virulence on a broader range of crops important to the region. Four isolates each of V. isaacii and V. klebahnii along with two reference isolates of V. dahliae races 1 and 2 were inoculated on eight crops (artichoke, cauliflower, eggplant, lettuce, pepper, tomato, spinach, and strawberry) in a greenhouse experiment. After 8 weeks, plants were assessed for disease severity to determine the relative host ranges of Verticillium isolates. Additionally, 13 lettuce lines resistant to race 1 and partially resistant to race 2 of V. dahliae were screened against V. isaacii and V. klebahnii to evaluate their responses. Three of four V. isaacii and four of four V. klebahnii isolates tested were nonpathogenic on all crops tested except those indicated below. One V. isaacii isolate caused wilt on artichoke and ‘Salinas’ lettuce and most isolates of both species caused varying degrees of Verticillium wilt on strawberry. Lettuce lines resistant to V. dahliae race 1 and partially resistant to V. dahliae race 2 also exhibited resistance to all of the isolates of V. isaacii and V. klebahnii. Thus, at least some isolates in the populations of V. isaacii and V. klebahnii have the potential to become significant pathogens of coastal California crops. However, resistance developed against V. dahliae also offers resistance to the pathogenic isolates of both species, at least in lettuce.

scholarly journals Pathogenic and Genetic Variation in the Japanese Strains of Fusarium oxysporum f. sp. melonis

1998 ◽  
Vol 88 (8) ◽  
pp. 804-810 ◽  
Author(s):  
Fumio Namiki ◽  
Toshiki Shiomi ◽  
Kazufumi Nishi ◽  
Tsuruo Kayamura ◽  
Takashi Tsuge
Keyword(s):  
Genetic Variation ◽  
Fusarium Oxysporum ◽  
Dna Sequences ◽  
Nuclear Markers ◽  
Oriental Melon ◽  
Genetic Groups ◽  
Pathogenic Variation ◽  
Pathogenicity Tests ◽  
Race 2 ◽  
Single Cluster

Pathogenic variation among 41 Japanese strains of Fusarium oxysporum f. sp. melonis was analyzed by pathogenicity tests with muskmelon, oriental melon, and oriental pickling melon cultivars. Based on pathogenicity to muskmelon cvs. Amus and Ohi and oriental melon cv. Ogon 9, 41 strains were divided into 3 groups that corresponded completely to Risser's races 0, 2, and 1,2y. To further characterize pathogenic variation within the forma specialis and races, strains were assayed for pathogenicity to 42 additional muskmelon, oriental melon, and oriental pickling melon cultivars. All strains of race 1,2y were pathogenic to all cultivars tested. Strains of race 0 were divided into six variants based on differences in pathogenicity to three muskmelon cultivars; strains of race 2 also were classified into six variants based on differences in pathogenicity to two muskmelon cultivars and one oriental melon cultivar. Genetic variation among strains was analyzed by DNA fingerprinting with four repetitive DNA sequences: FOLR1 to FOLR4. Thirty-six fingerprint types were detected among forty-one strains by pooling results of fingerprinting with four probes. Cluster analysis showed distinct genetic groups correlated with races: the fingerprint types detected in each of races 2 and 1,2y were grouped into a single cluster, and two distinct genetic groups were found in race 0. However, pathogenic variation detected within races 0 and 2 could not be differentiated based on the nuclear markers examined.

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 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.

scholarly journals First Report of Race 3 of Fusarium oxysporum f. sp. lycopersici in Southeastern Florida

Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 199-199
Author(s):  
R. C. Ploetz ◽  
J. L. Haynes
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Personal Communication ◽  
Crown Rot ◽  
Basal Cells ◽  
Single Spore ◽  
Tomato Cultivar ◽  
Race 1 ◽  
Race 2 ◽  
Research And Education

Race 3 of Fusarium oxysporum f. sp. lycopersici, cause of Fusarium wilt of tomato, Lycopersicon esculentum, was first recognized in Florida in 1982 on the west coast (Hillsborough and Manatee counties) (2). Approximately 10 years later, race 3 was reported in northeastern production areas of the state (Gadsden County) (1) and was observed on the east coast (Ft. Pierce area) (D. O. Chellemi, personal communication). During the 1998 to 1999 season, mature plants of Sanibel, a commercial tomato cultivar with resistance to races 1 and 2, were observed with symptoms of Fusarium wilt at the University of Florida's Tropical Research and Education Center in Homestead. Approximately 20% of the plants were conspicuously wilted, chlorotic, and necrotic in all or unilateral portions of the canopy. Internal, vascular discoloration in affected plants extended far into the canopy, distinguishing the disease from Fusarium crown rot, caused by F. oxysporum f. sp. radicis-lycopersici. Pure colonies of fungi were isolated from surface-disinfested (10 s with 70% ethanol, 2 min with 10% bleach) stem segments on potato dextrose agar (PDA) amended with streptomycin (100 mg/liter), rifamycin (50 mg/liter), and a commercial miticide (Danitol 2EHC [4 drops/liter]). Isolates were identified as F. oxysporum due to their production of typical falcate macroconidia with foot-shaped basal cells, microconidia borne in false heads only on mono-phialides, and chlamydospores. In replicated (three) greenhouse trials, six single-spore isolates were used to root-dip inoculate (107 conidia per ml) seedlings of differential tomato cultivars (Bonnie Best, no resistance; Manapal, race 1 resistance; Walter, race 1 and race 2 resistance). All isolates were pathogenic on each of the differential cultivars, and one isolate, 2-1, caused severe damage on Walter (mean rating of 3.5 on a 1 to 5 scale). The results were repeated in a second trial with the most virulent isolate. In both trials, pure colonies of F. oxysporum were recovered from symptomatic seedlings. Southeastern Florida is the last major tomatoproduction area in Florida to be affected by race 3 of F. oxysporum f. sp. lycopersici. References: (1) D. O. Chellemi and H. A. Dankers. Plant Dis. 76:861, 1992. (2) R. B. Volin and J. P. Jones. Proc. Fla. State Hortic. Soc. 95:268, 1982.

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