scholarly journals Vegetative Compatibility Groups and Aggressiveness of North American Isolates of Colletotrichum coccodes, the Causal Agent of Potato Black Dot

Plant Disease ◽  
2006 ◽  
Vol 90 (10) ◽  
pp. 1287-1292 ◽  
Author(s):  
N. Nitzan ◽  
L. Tsror (Lahkim) ◽  
D. A. Johnson
Keyword(s):  
North American ◽  
Average Frequency ◽  
Vegetative Compatibility ◽  
Colletotrichum Coccodes ◽  
North American Population ◽  
Black Dot ◽  
Vegetative Compatibility Groups ◽  
The North ◽  
Nit Mutants ◽  
Compatibility Group

The vegetative compatibility of 123 isolates of Colletotrichum coccodes from North America (United States and Canada) originating from potato, tomato, pepper, and mint was tested using nitrate-nonutilizing (nit) mutants. The North American isolates did not anastomose with previously selected European/Israeli vegetative compatibility group (VCG) testers; therefore, eight isolates were selected as VCG testers for the North American population. The 123 isolates distributed to seven VCGs at 1.6, 1.6, 4.0, 8.1, 13.8, 19.5, and 36.6%, with 14.6% of the isolates not assigned to any of the seven VCGs. Among the North American (NA)-VCGs, the average frequency of the nit1/nit3 nit mutants was lower (P < 0.05) for isolates belonging to NA-VCG1 than for isolates belonging to the NA-VCGs 2, 3, and 5. In contrast, the frequency of NitM nit mutants did not vary (P > 0.05) among the NA-VCGs and was collectively 5.14%. The results also indicated significant (P < 0.05) differences among NA-VCGs and European/Israeli (EU/I)-VCGs regarding the frequency of nit mutants. The aggressiveness trials of the North American isolates to potato indicated that plants infected with isolates belonging to NA-VCG2 and NA-VCG5 had more (P < 0.05) sclerotia on the roots and crowns than plants infected with isolates belonging to NA-VCGs 1 and 3. The plants infected with isolates belonging to NA-VCG2 had sclerotia formed higher (P < 0.05) up the stem than the plants infected with isolates belonging to NA-VCGs 1, 3, or 5. The plants infected with isolates assigned to NA-VCG2 had more (P < 0.05) infected progeny tubers than the plants infected with isolates belonging to NA-VCGs 1, 3, or 5; and the plants infected with isolates belonging to NA-VCGs 1, 2, and 5 yielded fewer (P < 0.05) potato tubers than the noninoculated control plants. A naming system for the population of C. coccodes based on the continent source of the population, the VCG number, and the isolate's code was suggested.

scholarly journals Vegetative Compatibility Groups in Colletotrichum coccodes, the Causal Agent of Black Dot on Potato

2002 ◽  
Vol 92 (8) ◽  
pp. 827-832 ◽  
Author(s):  
N. Nitzan ◽  
M. Hazanovsky ◽  
M. Tal ◽  
L. Tsror(Lahkim)
Keyword(s):  
Genetic Diversity ◽  
The Netherlands ◽  
Economic Importance ◽  
Vegetative Compatibility ◽  
Colletotrichum Coccodes ◽  
Black Dot ◽  
Vegetative Compatibility Groups ◽  
Nit Mutants ◽  
Pathogenicity Tests ◽  
Self Compatibility

Black dot of potato, caused by Colletotrichum coccodes, is a disease of growing economic importance, but the degree of genetic diversity and pathogenic differentiation among isolates is unknown. Using nitrate auxotrophic (Nit) mutants, we characterized vegetative compatibility groups (VCG) diversity for C. coccodes for 110 isolates originating from Israel, The Netherlands, and France. We recovered frequencies of nit1 and NitM mutant classes at 38.5 and 7.2%, respectively, and selected 12 isolates as tester isolates. Using these testers, we defined four multimember VCGs at 7.3, 35.5, 20.0, and 10.0% frequency in this sample. Thirty isolates (27.3% of all tested isolates) could not be assigned to any of the major groups, and showed only self-compatibility. The frequency of recovery of Nit mutant sectors was highest in isolates from VCG4, with 50.9 and 13.6% recovery for nit1 and NitM, respectively. However, we did not detect differences in the frequency of mutant classes among the three countries of origin. In pathogenicity tests, isolates from VCG3 were the most aggressive to potato, as expressed by high stem colonization levels and sclerotia density on root and crown. These results suggest that there is significant VCG diversity in this species and that this VCG diversity may be correlated with pathogenic characteristics or specialization.

scholarly journals Variability in Morphology and Aggressiveness Among North American Vegetative Compatibility Groups of Colletotrichum coccodes

2008 ◽  
Vol 98 (8) ◽  
pp. 901-909 ◽  
Author(s):  
A. M. Aqeel ◽  
J. S. Pasche ◽  
N. C. Gudmestad
Keyword(s):  
North American ◽  
Vegetative Compatibility ◽  
Colletotrichum Coccodes ◽  
Inoculum Potential ◽  
Tuber Weight ◽  
Vegetative Compatibility Groups ◽  
Inoculation Methods ◽  
Length Width ◽  
Potato Foliage ◽  
Pathogenic Variability

North American isolates of Colletotrichum coccodes, representing six vegetative compatibility groups (NA-VCG), were used to study morphological and pathogenic variability. The objective was to determine if variability in conidial and microsclerotial size was related to pathogenicity. Significant differences were detected in length, width, and length/width ratios of conidia as well as in the length and width of microsclerotia among the NA-VCGs. The longest and widest conidia were produced by isolates belonging to NA-VCG1 and the largest microsclerotia were produced by isolates of NA-VCG2. Conidial and microsclerotial lengths and widths also were affected significantly by type of growth medium. There was no relationship between the size of conidia and the size of microsclerotia among the NA-VCGs studied. Conidial and microsclerotial size may affect inoculum potential and survival as isolates of NA-VCG2 have been demonstrated to occur more frequently than other NA-VCGs. Aggressiveness of 17 isolates of C. coccodes representing six NA-VCG's was studied on three potato cultivars using foliar and root inoculation methods. C. coccodes infection reduced tuber weight in all cultivars with both inoculation methods although tuber weight reductions were significantly higher following root inoculations than foliar inoculations. Pathogenic aggressiveness varied among NA-VCGs. Isolates belonging to NA-VCG2 and 3 were the least aggressive on potato foliage and isolates of NA-VCG1, 2, 3, 4, and 5 produced higher microsclerotial density on all three cultivars compared with isolates of NA-VCG6. Across inoculation methods, isolates of C. coccodes belonging to NA-VCG2 and 6 were the most aggressive based on reductions in tuber weight. Umatilla Russet was the most susceptible cultivar to C. coccodes compared to other cultivars regardless of inoculation method. These results demonstrate variability in morphology and pathogenic aggressiveness among the NA-VCGs of C. coccodes but these traits are not related.

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.

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 Additional Vegetative Compatibility Groups in Colletotrichum coccodes Subpopulations from Europe and Israel

Plant Disease ◽  
2007 ◽  
Vol 91 (7) ◽  
pp. 805-808 ◽  
Author(s):  
S. Shcolnick ◽  
A. Dinoor ◽  
L. Tsror (Lahkim)
Keyword(s):  
The Netherlands ◽  
Vegetative Compatibility ◽  
Northern Europe ◽  
Colletotrichum Coccodes ◽  
Tuber Quality ◽  
Potato Tubers ◽  
Black Dot ◽  
Damage Potential ◽  
Vegetative Compatibility Groups ◽  
Accurate Evaluation

Potato black dot, caused by Colletotrichum coccodes, damages tuber quality and may reduce yield. In previous work, four multimember vegetative compatibility groups (VCGs) have been reported. The objectives of the current study were to characterize a population of C. coccodes comprised of isolates from Israel and Northern Europe (EU/I) using VCG, and to assess the correlation between VCGs and aggressiveness of isolates on potato. A composite of 176 isolates was collected from symptomatic tissues of potato tubers or stems. A total of 6 (3.4%) isolates were characterized in VCG1; 29 (16.5%), 32 (18.2%), and 7 (4.0%) in VCG 2, 3, and 4, respectively; and 7 (4.0%), 9 (5.1%), 48 (27.3%), and 15 (8.5%) in the newly defined VCG 5, 6, 7, and 8, respectively. Twenty-three isolates (13%) were not assigned to any of the VCGs. Two of the VCGs had a specific geographical distribution: the 9 isolates assigned to VCG6 originated from The Netherlands, and 34 of 38 isolates assigned to VCG7 were from Scotland. Aggressiveness of isolates of a given VCG was examined on potato. VCGs 5 and 6 were comprised of the most aggressive isolates, and VCG1 of the least aggressive. These results could facilitate a more accurate evaluation of damage potential that may be caused by this pathogen.

scholarly journals Vegetative Compatibility Groups in Colletotrichum coccodes Subpopulations from Australia and Genetic Links with Subpopulations from Europe/Israel and North America

2010 ◽  
Vol 100 (3) ◽  
pp. 271-278 ◽  
Author(s):  
B. Ben-Daniel ◽  
D. Bar-Zvi ◽  
D. Johnson ◽  
R. Harding ◽  
M. Hazanovsky ◽  
...  
Keyword(s):  
Gene Flow ◽  
North America ◽  
The Netherlands ◽  
Vegetative Compatibility ◽  
Colletotrichum Coccodes ◽  
Vegetative Incompatibility ◽  
Vegetative Compatibility Groups ◽  
Nit Mutants ◽  
First Time ◽  
Limited Exchange

Vegetative compatibility of 94 isolates of Colletotrichum coccodes from Australia originating from potato, soil, and a weed (Solanum esuriale) was tested using nitrate-nonutilizing (nit) mutants. Isolates distributed to six vegetative compatibility groups (VCGs), five of them multimember (24.5, 23.4, 13.8, 12.8, and 7.5% distribution) and only one composed of two isolates (2.1%); 15.9% of them were not assigned to any of the VCGs. Aggressiveness of 51 isolates representing all six VCGs was tested by mature green tomato bioassay: isolates assigned to AUS-VCG-4 were the most aggressive and those in AUS-VCG-3 the least (P < 0.05). Isolates from warmer climates and lower latitudes were more aggressive (P < 0.05). In addition, we report for the first time complementations between isolates from Australia (AUS); North America (NA); and Israel, The Netherlands, Scotland, France, Germany (EU/I). Isolates assigned to AUS-VCG-4 anastomosed with isolates assigned to EU/I-VCG-7 and NA-VCG-5 (which also anastomosed with each other). Isolates assigned to EU/I-VCG-6 anastomosed with isolates assigned to NA-VCG-2 and isolates assigned to AUS-VCG-2 anastomosed with isolates assigned to EU/I-VCG-2. The linkage between subpopulations could result from the limited exchange of seed tubers among continents, or could be due to, for instance, gene flow, selection, or a limited number of polymorphic vegetative incompatibility genes.

scholarly journals Genetic Variability of Cercospora coffeicola from Organic and Conventional Coffee Plantings, Characterized by Vegetative Compatibility

2008 ◽  
Vol 98 (11) ◽  
pp. 1205-1211 ◽  
Author(s):  
R. B. Martins ◽  
L. A. Maffia ◽  
E. S. G. Mizubuti
Keyword(s):  
Genetic Variability ◽  
Production Systems ◽  
Diversity Index ◽  
Vegetative Compatibility ◽  
Cercospora Leaf Spot ◽  
Vegetative Compatibility Groups ◽  
Nit Mutants ◽  
Geographical Regions ◽  
Minas Gerais State ◽  
Cercospora Coffeicola

Cercospora leaf spot is a destructive fungal disease that has become a threat to the coffee industry in Brazil. Nevertheless, little is known about populations of its causal agent, Cercospora coffeicola. We evaluated the potential of using nitrogen-nonutilizing (nit) mutants and vegetative compatibility groups (VCGs) to characterize the genetic variability of the C. coffeicola population associated with coffee plantings in Minas Gerais state (MG), Brazil. A total of 90 monosporic isolates were obtained from samples collected according to a hierarchical sampling scheme: (i) state geographical regions (Sul, Mata, and Triângulo), and (ii) production systems (conventional and organic). Nit mutants were obtained and 28 VCGs were identified. The 10 largest VCGs included 72.31% of all isolates, whereas each of the remaining 18 VCGs included 1.54% of the isolates. Isolates of the largest VCGs were found in the three regions sampled. Based on the frequencies of VCGs at each sampled level, we estimated the Shannon diversity index, as well as its richness and evenness components. Genetic variability was high at all hierarchical levels, and a high number of VCGs was found in populations of C. coffeicola associated with both conventional and organic coffee plantings.

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.

scholarly journals Relationship Among Breeding, Molting, and Wintering Areas of Male Barrow's Goldeneyes (Bucephala Islandica) in Eastern North America

The Auk ◽  
2002 ◽  
Vol 119 (3) ◽  
pp. 676-684 ◽  
Author(s):  
Michel Robert ◽  
Réjean Benoit ◽  
Jean-Pierre L. Savard
Keyword(s):  
North American ◽  
River Estuary ◽  
North American Population ◽  
American Population ◽  
Adult Males ◽  
Breeding Area ◽  
The North ◽  
Bucephala Islandica ◽  
The Mean ◽  
St Lawrence River

Abstract Little is known of the eastern North American population of Barrow's Goldeneyes (Bucephala islandica), which was recently listed as “of special concern” in Canada. In 1998 and 1999, we marked 18 adult males wintering along the St. Lawrence River, Québec, with satellite transmitters to document their breeding, molting, and wintering distribution and phenology, and to describe timing and routes of their spring, molt, and fall migrations. Thirteen males moved inland from the St. Lawrence River to breed; the spring migration averaged 5.9 days, and birds arrived on breeding areas on average 9 May. All breeding areas were inland, on the north shore of the St. Lawrence River estuary and gulf. Breeding areas averaged 64.8 km from the St. Lawrence corridor. Males stayed on their respective breeding area a mean of 34.5 days, and left on average 11 June. Twelve males were tracked to their molting areas, one of which stayed on its wintering area until 5 June and flew directly to its molting area. Their molt migration averaged 18.6 days, and the mean arrival date on molting areas was 30 June. All molting areas were located north and averaged 986 km from breeding areas. Four males molted in Hudson Bay, four in Ungava Bay, two in northern Labrador, one on Baffin Island, and one inland, near the Québec–Labrador border. The mean length of stay on the molting areas was 105.3 days, and the mean date of departure from molting areas was 4 October. All goldeneyes for which the radio still functioned during fall migration returned to winter in the St. Lawrence River estuary, on average 6 November. Our results refute the idea that the main breeding area of the eastern North American population of Barrow's Goldeneyes is located in northern Québec and Labrador and rather indicate that it is in the boreal forest just north of the St. Lawrence River estuary and gulf. They also indicate that Barrow's Goldeneye males undertake a genuine molt migration, and highlight the importance of molting areas because birds stayed there approximately four months each year.

Genetic Variability in the Potato Pathogen Colletotrichum coccodes as Determined by Amplified Fragment Length Polymorphism and Vegetative Compatibility Group Analyses

2006 ◽  
Vol 96 (10) ◽  
pp. 1097-1107 ◽  
Author(s):  
Larry J. Heilmann ◽  
Nadav Nitzan ◽  
Dennis A. Johnson ◽  
Julie S. Pasche ◽  
Curt Doetkott ◽  
...  
Keyword(s):  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Amplified Fragment Length Polymorphism ◽  
Vegetative Compatibility ◽  
Colletotrichum Coccodes ◽  
Aflp Analysis ◽  
Aflp Data ◽  
Bootstrap Analysis ◽  
Nit Mutants

Amplified fragment length polymorphism (AFLP) using three primer sets was used to characterize 211 Colletotrichum coccodes isolates from North America, 112 of which were assigned to six vegetative compatibility groups (VCGs) using nitrate nonutilizing (nit) mutants. These isolates clustered into five corresponding groups by unweighted pairgroup method with arithmetic means-based cluster analysis of AFLP banding patterns. Isolates of C. coccodes belonging to NA-VCG1 and NA-VCG3 were closely related, as were isolates belonging to NA-VCG2 and NA-VCG5. Based on bootstrap analysis of AFLP data, the two isolates originally assigned to NA-VCG4 clustered with isolates belonging to NA-VCG2 and NA-VCG5. C. coccodes isolates that clustered with two isolates belonging to NA-VCG6 were the most diverged from other groups, including seven isolates collected from hosts other than potato. As opposed to the bootstrap analysis, a quadratic discriminant analysis (QDA) of AFLP data correctly categorized the two isolates of NA-VCG4. Furthermore, in isolates where VCG determinations had been made, this model correctly classified isolates of all VCGs. QDA classifications were identical to those made by the bootstrap analysis, with the exception of VCG4. Overall, classifications made by the QDA model were strongly correlated (r = 0.970, P < 0.001) to the VCGs assigned by traditional methods. All 99 C. coccodes isolates evaluated only by AFLP also were subjected to QDA, leading to the assignment of a presumptive VCG for each isolate. No isolates of VCG4 or VCG6 were identified by QDA within this population. Symptoms of black dot developed in plants inoculated with isolates collected from both potato and non-potato hosts. However, total yield was not significantly reduced by infection with non-potato isolates. The lack of any additional groups identified by AFLP analysis may be an indicator of a limited level of genetic variation among North American C. coccodes isolates. AFLP is a much more efficient technique for subspecific characterization in C. coccodes than VCG analysis utilizing nit mutants and will provide an effective means by which the population biology of this pathogen can be further investigated worldwide.

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