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.

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.

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.

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 Morphologic, Molecular, and Pathogenic Characterization of Diaporthe phaseolorum Variability in the Core Soybean-Producing Area of Argentina

2003 ◽  
Vol 93 (2) ◽  
pp. 136-146 ◽  
Author(s):  
Rosanna N. Pioli ◽  
Eligio N. Morandi ◽  
María C. Martínez ◽  
Florencia Lucca ◽  
Alejandro Tozzini ◽  
...  
Keyword(s):  
Random Amplified Polymorphic Dna ◽  
Intraspecific Variability ◽  
Principal Component ◽  
Stem Canker ◽  
Avirulence Genes ◽  
Physiological Races ◽  
The Core ◽  
Growing Seasons ◽  
Diaporthe Phaseolorum ◽  
Soybean Genotypes

Isolates of the Diaporthe/Phomopsis (D/P) complex were collected in the main soybean producing area of Argentina during the 1996-97, 1997-98, and 1998-99 growing seasons. Twenty-three morphologic characters related to type of colonies, stroma, pycnidia and conidia, presence of perithecia, and asci length were studied by principal component analysis (PCA). Genomic DNA were analyzed by the random amplified polymorphic DNA (RAPD) technique. From both studies, 18 isolates were identified as D/P complex and grouped in four major taxa: (i) Diaporthe phaseolorum var. meridionalis, (ii) D. phaseolorum var. caulivora, (iii) D. phaseolorum var. sojae, and (iv) Phomopsis longicolla. In addition to distinguishing interspecific and intraspecific variability, molecular markers allowed the detection of differences among isolates within the same variety. Pathogenicity was assayed in the greenhouse, by the toothpick method, inoculating the D/P isolates to soybean genotypes carrying different resistance genes (Rdc1, Rdc2, Rdc3, and Rdc4) against soybean stem canker (SSC). Pathogenic analysis distinguished two main groups: (i) the SSC-producing isolates, including D. phaseolorum var. meridionalis and D. phaseolorum var. caulivora, and (ii) the non-SSC-producing isolates, including D. phaseolorum var. sojae and P. longicolla. Cultivar RA-702 (susceptible control) was compatible with both D. phaseolorum var. meridionalis and D. phaseolorum var. caulivora isolates; meanwhile, Tracy-M (Rdc1 and Rdc 2 genes) was incompatible with D. phaseolorum var. meridionalis but compatible with D. phaseolorum var. caulivora isolates. The fact that Rdc1 and Rdc2 together (as in Tracy-M) confer an almost immune reaction to all assayed isolates of D. phaseolorum var. meridionalis but were ineffective against the D. phaseolorum var. caulivora isolates evaluated suggests that the virulence or avirulence genes in D. phaseolorum var. meridionalis and D. phaseolorum var. caulivora are different. Moreover, physiological races of D. phaseolorum var. meridionalis were detected by using differential soybean genotypes carrying distinct single Rdc genes. As far as we know, this is the first report on the existence of physiological races of D. phaseolorum var. meridionalis in South America. Selective pressure due to deployment of resistant host cultivars may have changed the frequency of the virulence or avirulence genes within the population of D. phaseolorum var. meridionalis. On the whole, our results show that pathogenic variability of D. phaseolorum in the core soybean-producing area of Argentina is higher than previously recognized.

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.

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