Evidence for homothallism and vegetative compatibility in southern Diaporthe phaseolorum

1986 ◽  
Vol 64 (10) ◽  
pp. 2197-2200 ◽  
Author(s):  
R. C. Ploetz ◽  
F. M. Shokes
Keyword(s):  
Southeastern United States ◽  
Lima Bean ◽  
Stem Canker ◽  
Potato Dextrose Agar ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Groups ◽  
Diaporthe Phaseolorum ◽  
Compatibility Group ◽  
Cornmeal Agar ◽  
Group 1

Twenty-nine vegetative compatibility groups (vcgs) were identified among 297 isolates of the fungus causing soybean stem canker in the southeastern United States (southern Diaporthe phaseolorum). Of the isolates characterized, 79% were from one of the vcgs described (group 1). Barrage zones formed between isolates from different vcgs when grown on potato dextrose agar, and also formed, but not always distinctly, on cornmeal agar, Czapek-Dox agar, lima bean agar, and malt agar; barrages did not form on Sach's agar or water agar. Two types of evidence suggested that southern D. phaseolorum is homothallic. Perithecia and viable ascospores were produced by single ascospore isolates, and ascospores produced by mass isolates were always of the same compatibility group as the parental mass isolate.

Variability among isolates of Diaporthe phaseolorum f.sp. meridionalis in different vegetative compatibility groups

1989 ◽  
Vol 67 (9) ◽  
pp. 2751-2755 ◽  
Author(s):  
R. C. Ploetz ◽  
F. M. Shores
Keyword(s):  
Growth Rates ◽  
Southeastern United States ◽  
Stem Canker ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Groups ◽  
Future Studies ◽  
Diaporthe Phaseolorum ◽  
Soybean Genotypes ◽  
Compatibility Group

Members of 1 of 29 previously described vegetative compatibility groups of Diaporthe phaseolorum f.sp. meridionalis (causal agent of soybean stem canker in the southeastern United States) predominated in epidemic populations from Alabama, Georgia, Florida, and Tennessee. Factors that might explain the prevalence of vegetative compatibility group (VCG) 1 were examined in studies with members of this and other VCGs of the pathogen. The virulence of isolates within six different VCGs on eight different soybean genotypes was similar, and variation among VCGs supported previous reports of diverse virulence in Diaporthe phaseolorum f.sp. meridionalis. Isolates within different VCGs also had similar in vitro growth rates and sensitivities to fungicides used either for controlling diseases of soybean in the Southeast (benomyl) or as an ingredient in a medium that is used to selectively isolate the pathogen (triadimefon). Since members of VCG 1 did not possess exceptional virulence, growth rates, or insensitivities to benomyl or triadimefon, the prevalence of VCG 1 could not be explained by these factors. However, relating these and other characteristics of Diaporthe phaseolorum f.sp. meridionalis to a biologically significant characteristic such as vegetative compatibility would provide a logical framework by which isolates and populations of the pathogen could be evaluated in future studies.

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.

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.

Pathogenicity and vegetative compatibility among isolates of Fusarium oxysporum and F. moniliforme colonizing asparagus tissues

1989 ◽  
Vol 67 (8) ◽  
pp. 2420-2424 ◽  
Author(s):  
J. A. LaMondia ◽  
W. H. Elmer
Keyword(s):  
Fusarium Moniliforme ◽  
Vegetative Compatibility ◽  
Asparagus Officinalis ◽  
Symptom Expression ◽  
Old Field ◽  
Storage Roots ◽  
Vegetative Compatibility Groups ◽  
Nit Mutants ◽  
Compatibility Group ◽  
Stem Segments

Isolates of Fusarium moniliforme (Sheld.) emend. Snyd. & Hans., F. oxysporum (Schlecht) emend. Snyd. & Hans., and F. solani (Mart.) Appel & Wollenw. emend. Snyd. & Hans. were recovered from three 5-year-old field grown asparagus (Asparagus officinalis L. cv. Mary Washington) by isolating from symptomatic and asymptomatic feeder roots, storage roots, crown and basal stem segments. Fusarium moniliforme was more virulent than F. oxysporum on asparagus seedlings and F. solani was considered nonpathogenic. Isolates of F. moniliforme and F. oxysporum were placed into vegetative compatibility groups (VCGs) by demonstrating heterokaryosis with complementation tests using nitrate-nonutilizing (nit) mutants (pairing nitM and nit1 mutants). Ninety-seven of 135 isolates of F. moniliforme were placed in 13 vegetative compatibility groups. The remaining 38 isolates were not classified by vegetative compatibility because of poor nit mutant recovery. Eight of 18 isolates of F. oxysporum were unique and classed as single members of eight different VCGs. The other 10 isolates were not placed in VCGs. All isolates of F. moniliforme were virulent, but mean disease ratings differed among the isolates in different VCGs. There was no correlation between vegetative compatibility group and tissue substrate or symptom expression on the tissue substrate. It appears that virulence on asparagus is a common trait with few exceptions among genetically distinct populations of F. moniliforme and F. oxysporum colonizing asparagus.

scholarly journals Molecular Characterization of Vegetative Compatibility Group 4A and 4B Isolates of Verticillium dahliae Associated with Potato Early Dying

Plant Disease ◽  
2000 ◽  
Vol 84 (11) ◽  
pp. 1241-1245 ◽  
Author(s):  
K. F. Dobinson ◽  
M. A. Harrington ◽  
M. Omer ◽  
R. C. Rowe
Keyword(s):  
New York ◽  
Molecular Markers ◽  
Verticillium Dahliae ◽  
Vegetative Compatibility ◽  
Potato Seed ◽  
Potato Early Dying ◽  
Vegetative Compatibility Groups ◽  
Length Polymorphisms ◽  
Compatibility Group ◽  
Early Dying

Forty isolates of Verticillium dahliae, collected from potato seed tubers and potato plants from various regions in North America and previously assigned to vegetative compatibility groups (VCGs) 4A or 4B, were characterized using molecular markers. The VCG 4A isolates were previously shown to be a highly virulent pathotype of potato and to interact synergistically with the root-lesion nematode Pratylenchus penetrans to cause potato early dying. All but one of the VCG 4A isolates characterized in this study lacked the subspecies-specific repetitive DNA sequence E18 and could be differentiated from the remaining isolates by restriction fragment length polymorphisms (RFLPs) in the nuclear rDNA and Trp1 loci. The E18 RFLP patterns of several VCG 4B isolates from Maine and New York were highly similar to those of VCG 4B isolates previously collected from potato and tomato fields in Ontario. The data presented here suggest that the molecular markers will be useful for the detection and classification of isolates of V. dahliae associated with potato early dying.

A rose bengal amended medium for selecting nitrate-metabolism mutants from fungi

1995 ◽  
Vol 73 (4) ◽  
pp. 680-682 ◽  
Author(s):  
Karol S. Elias ◽  
Peter J. Cotty
Keyword(s):  
Rose Bengal ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Vegetative Compatibility Groups ◽  
Fusarium Lateritium ◽  
Compatibility Group ◽  
Nitrate Metabolism ◽  
Macroscopic Observation ◽  
The Rose ◽  
Selection Of

A rose bengal amended medium for selecting nitrate-metabolism mutants from fungi with reduced sensitivity to chlorate is described. Isolates of several species known to resist development of nitrate-metabolism mutants on chlorate medium formed such mutants when grown on the rose bengal – chlorate medium. These species include Aspergillus flavus (Link.), Fusarium lateritium (Nees ex Link.), Fusarium oxysporum (Schlecht.), Fusarium solani (Mart.) Sacc., Alternaria cassiae (Jurair and Khan), Alternaria macrospora (Zimmerman), and Alternaria tagetica (Shome and Mustafee). The medium allows selection of nitrate-metabolism mutants of certain fungal strains for which chlorate-based techniques have not been satisfactory. Resulting mutants, following phenotype determination and identification of complementary testers, can be paired to enable macroscopic observation of heterokaryon formation during vegetative compatibility analyses. Thus, this medium may facilitate development of information on delimitation of vegetative compatibility groups among strains within these taxa. Key words: chlorate resistance, population structure, vegetative compatibility group, VCG.

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 Occurrence of Diaporthe phaseolorum var. meridionalis on Soybean in Illinois

Plant Disease ◽  
2001 ◽  
Vol 85 (11) ◽  
pp. 1211-1211 ◽  
Author(s):  
C. E. Gravert ◽  
S. Li ◽  
G. L. Hartman
Keyword(s):  
Stem Canker ◽  
The United States ◽  
The State ◽  
Potato Dextrose Agar ◽  
Phomopsis Longicolla ◽  
Growing Seasons ◽  
Irregular Shapes ◽  
Diaporthe Phaseolorum ◽  
Northern Regions ◽  
Soybean Plants

Both Diaporthe phaseolorum var. caulivora and D.phaseolorum var. meridionalis cause stem canker on soybean, with D. phaseolorum var. caulivora reported in the northern regions and D. phaseolorum var. meridionalis reported in the southern regions of the United States (1). During the 1999 and 2000 growing seasons, fungi were isolated from soybean plants from growers' fields exhibiting stem canker symptoms. Stem tissue along the margin of the canker was cut into 1- to 5-mm3 pieces, surface-disinfected for 4 min in 0.5% NaOCl solution, rinsed twice, and plated on water or potato dextrose agar (PDA). Fungi of interest were hyphal tipped, grown on PDA at 21°C with 24 h of light, and identified by culture and spore morphology after 3 to 4 weeks. Typical D. phaseolorum var. meridionalis isolates produced white, lanose colonies that turned tan with age. Most of the D. phaseolorum var. meridionalis isolates produced pycnidia with alpha spores and beaked perithecia after 25 to 30 days (2). Brown to black stromata formed in irregular shapes. Of the 16 D. phaseolorum var. meridionalis isolates identified, 11 were from Illinois, 1 each from Indiana and Ohio, and 3 from Kentucky. In Illinois, four isolates were from the northern part of the state, and the rest were from the central and southern areas of the state. In addition to D. phaseolorum var. meridionalis, other isolates obtained from soybean plants included D. phaseolorum var. caulivora, D. phaseolorum var. sojae, and Phomopsis longicolla. References: (1) J. A. McGee and D. C. Biddle. Plant Dis. 71:620, 1987. (2) A. W. Zhang et al. Phytopathology 88:1306, 1998.

Vegetative compatibility groups and protein electrophoresis indicate a role for basidiospores in spread of Inonotus tomentosus in spruce forests of British Columbia

1991 ◽  
Vol 69 (8) ◽  
pp. 1756-1763 ◽  
Author(s):  
Katherine J. Lewis ◽  
Everett M. Hansen
Keyword(s):  
British Columbia ◽  
Key Words ◽  
Picea Glauca ◽  
Protein Electrophoresis ◽  
Vegetative Compatibility ◽  
Protein Profiles ◽  
Vegetative Compatibility Group ◽  
Protein Patterns ◽  
Vegetative Compatibility Groups ◽  
Compatibility Group

The importance of spore infection in the spread of Inonotus tomentosus was assessed using vegetative compatibility and protein electrophoresis. Isolates were collected from diseased spruce (Picea glauca × engelmannii) trees from five sites. Each site had several small (two or three trees) discrete disease centres, or larger patchy centres, or both. Within each site, the vegetative compatibility group and protein profiles of isolates were examined in all combinations of paired isolates. Vegetatively compatible isolates had identical protein profiles in 74% of the comparisons. Vegetatively incompatible isolates had different protein profiles 97% of the time. Usually isolates differed by only one or two protein bands. Isolates from a discrete centre were usually vegetatively compatible with identical protein patterns. Larger patchy centres consisted of multiple vegetatively compatible groups. The number of unique vegetatively compatible groups found suggests that spores are an important course of infection. Key words: vegetative compatibility, disease centre, protein electrophoresis.

scholarly journals Sexual Recombination in Gibberella zeae

1999 ◽  
Vol 89 (2) ◽  
pp. 182-188 ◽  
Author(s):  
Robert L. Bowden ◽  
John F. Leslie
Keyword(s):  
The United States ◽  
Vegetative Compatibility ◽  
Gibberella Zeae ◽  
Rapid Testing ◽  
Wild Type ◽  
Vegetative Compatibility Groups ◽  
Nit Mutants ◽  
Sexual Recombination ◽  
Group 2 ◽  
Group 1

We developed a method for inducing sexual outcrosses in the homothallic Ascomycete fungus Gibberella zeae (anamorph: Fusarium graminearum). Strains were marked with different nitrate nonutilizing (nit) mutations, and vegetative compatibility groups served as additional markers in some crosses. Strains with complementary nit mutations were cocultured on carrot agar plates. Ascospores from individual perithecia were plated on a minimal medium (MM) containing nitrate as the sole nitrogen source. Crosses between different nit mutants segregated in expected ratios (3:1 nit-:nit+) from heterozygous perithecia. Analysis of vegetative compatibility groups of progeny of two crosses indicated two and three vegetative incompatibility (vic) genes segregating, respectively. For rapid testing of sexual recombination between nit mutants, perithecia were inverted over MM to deposit actively discharged ascospores. Development of proto-trophic wild-type colonies was taken as evidence of sexual recombination. Strains of G. zeae group 2 from Japan, Nepal, and South Africa, and from Indiana, Kansas, and Ohio in the United States were sexually interfertile. Four group 1 strains were not interfertile among themselves or with seven group 2 strains. Attempts to cross G. zeae with representatives of F. acuminatum, F. avenaceum, F. culmorum, F. crookwellense, F. oxysporum, and three mating populations of G. fujikuroi were not successful.

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