			Home About us Contact

Vegetative Compatibility (vegetative + compatibility)

Distribution by Scientific Domains

Life Sciences	100%

Terms modified by Vegetative Compatibility

vegetative compatibility group

vegetative compatibility groups

Selected Abstracts

Vegetative Compatibility Among Isolates of Colletotrichum gloeosporioides from Yam (Dioscorea spp.) in Nigeria

JOURNAL OF PHYTOPATHOLOGY, Issue 1 2004
M. M. Abang
Abstract Isolates of Colletotrichum gloeosporioides obtained from yam-based cropping systems in Nigeria, previously characterized on the basis of morphology, virulence and rDNA internal transcribed spacer (ITS) sequence variation were further compared for vegetative compatibility (VC). Chlorate-resistant nitrate non-utilizing (nit) mutants were generated from the isolates and used in complementation (heterokaryon) tests. Tests of VC between complementary mutants from different isolates indicated the presence of several genotypes within a single field, suggesting limited clonal spread. In some cases, isolates obtained from the same lesion were observed to belong to different vegetative compatibility groups (VCGs). No compatibility was observed between isolates of the highly virulent slow-growing grey (SGG), the moderately virulent fast-growing salmon (FGS) and the avirulent/weakly virulent fast-growing grey (FGG) strains. Forty-one C. gloeosporioides isolates belonged to 28 VCGs, giving a genotype diversity estimate of 0.68. This diversity confirmed the high variability of the pathogen population as revealed by previous characterization studies, however, a correlation between VCGs and isolate groupings based on morphology and virulence was not found. The finding that an isolate from weed was compatible with yam isolates indicated that transfer of important traits, such as virulence, may take place between isolates from yam and non-yam hosts. The VCG diversity revealed by this study suggests that in addition to asexual reproduction, sexual reproduction may play an important role in the epidemiology of anthracnose on yam. [source]

Vegetative Compatibility and Pathogenicity of Verticillium dahliae Kleb.

JOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2003
Isolates from Olive in Israel
Abstract Fifty-two isolates of Verticillium dahliae from olive trees grown at different locations in Israel were assigned to vegetative compatibility groups (VCGs), using nitrate non-utilizing (Nit) mutants. A higher frequency of nit1/nit3 mutants (95%) was obtained compared with NitM (5%), with 81% of the isolates being assigned to VCG4B and 19% to VCG2A. The pathogenicity of 14 randomly selected isolates (seven of each VCG) was tested on olive twigs (cv. Picual) and tomato. VCG4B and VCG2A isolates were similarly aggressive on olive. However, VCG2A isolates were more aggressive on tomato (line 139) than the VCG4B isolates as indicated by a higher colonization index. [source]

Pathogenicity and Vegetative Compatibility of Fusarium oxysporum f. sp. phaseoli in Greece

JOURNAL OF PHYTOPATHOLOGY, Issue 8-9 2002
K. Elena
Abstract Twenty-seven isolates of Fusarium oxysporum (Fo) obtained from diseased beans from Greece were characterized for pathogenicity to bean cultivars and vegetative compatibility (VCG). Twenty-three isolates were intermediate to highly virulent to five local bean cultivars and characterized as F. oxysporum f. sp. phaseoli (Fop). Zarganes, Gigantes (two selections) and Chondra were the most susceptible cultivars, while Psila was resistant to 10 of the isolates. Four Fo isolates were not pathogenic against tested cultivars. By demonstrating complementation assay, with nitrate non-utilizing (nit) mutants, 15 pathogenic isolates were grouped into one VCG, two isolates into a previously identified VCG 0165 and six into unique unclassified VCGs. The four non-pathogenic Fo isolates failed to anastomose with any tested pathogenic Fop strain. Our results suggest that most of Fop isolates in Greece belong to one VCG. [source]

Vegetative compatibility and heterokaryon stability in Fusarium oxysporum f.sp. radicis-lycopersici from Italy

PLANT PATHOLOGY, Issue 3 2001
P. Di Primo
Fusarium crown and root rot, caused by Fusarium oxysporum f.sp. radicis-lycopersici (Forl), is one of the most destructive soilborne diseases of tomato in Italy. Chlorate-resistant, nitrate-nonutilizing (nit) mutants were used to determine vegetative compatibility among 191 isolates of Forl collected in five geographic regions (Calabria, Emilia-Romagna, Liguria, Sardinia, Sicily) in Italy. The isolates were assigned to five vegetative compatibility groups (VCGs): 65 isolates to VCG 0090; 99 to VCG 0091; 23 to VCG 0092; two to VCG 0093; and two to VCG 0096. The population structure of Forl in Italy is similar to that reported for Israel, and differs from that found in North Atlantic European countries, where VCG 0094 is predominant. The stability of prototrophic heterokaryons originating from hyphal anastomosis between compatible complementary nit mutants was assessed through conidial analysis and mycelial mass transfer. Most monoconidial cultures (84%) recovered from 117 prototrophic heterokaryons were nit mutants, indicating that heterokaryons generally do not proliferate well through conidiation; most of the 177 prototrophic heterokaryons examined were unstable, and only 9% sustained prototrophic growth through the tenth mycelial transfer upon subculturing. The prototrophic growth is proposed to be maintained through restoration of the heterokaryotic state by continual anastomosis between adjacent homokaryotic hyphae. Since heterokaryosis is a prerequisite for parasexual recombination, we speculate that this mechanism is unlikely to play a major role in generating the VCG diversity found among Forl or other strains of F. oxysporum. [source]

Incomplete movement of Cryphonectria hypovirus 1 within a vegetative compatibility type of Cryphonectria parasitica in natural cankers on grafted American chestnut trees

FOREST PATHOLOGY, Issue 6 2002
E. P. Hogan
Summary American chestnut trees, grafted in 1980 from large survivors, were inoculated in 1982 and 1983 with four white (European) hypovirulent strains of Cryphonectria parasitica, infected with C. hypovirus 1 (CHV1); this hypovirus has been shown to be capable of moving rapidly within the mycelium of a vegetative compatibility (vc) type of C. parasitica in blight cankers. Using a 49-cell lattice plot, 17.8×17.8 cm, the spatial patterns and frequencies of white and pigmented isolates and white and pigmented vc types were investigated within superficial cankers on the grafts located outside the hypovirulent-strain-inoculated zone. Four of six cankers assayed contained white isolates, and three of the four had random spatial patterns of white isolates, based on join-count statistics. Vc tests, using pigmented isolates and pigmented single-spore colonies of white isolates, indicated that the majority of white and pigmented isolates recovered from each of two cankers assayed were in one vc type. White and pigmented lattice-plot cells of the same vc type were frequently in contact with each other, indicating incomplete movement of CHV1 within a vc type. Nine and 10 vc types were found in the two cankers; it is hypothesized that small, white vc type areas in each canker may be a source of CHV1 transmission to the major vc types. Based on join-count statistics, the spatial pattern of the single, major vc type in one canker was non-random (aggregated), whereas the other canker had a random major vc type pattern. White and pigmented in vitro variants (sectors) of C. parasitica, that resemble white and pigmented in vivo variants in spatial contact and vc compatibility, were intermediate hypovirulent and virulent on forest American chestnuts, and dsRNA positive and negative, respectively. Incomplete movement of CHV1 within a vc type could be a major cause of the prevalence of pigmented isolates in superficial cankers on chestnut trees. Résumé Des châtaigniers américains greffés en 1980 à partir de grands arbres survivants, ont été inoculés en 1982 et 1983 avec quatre souches blanches (européennes) hypovirulentes de Cryphonectria parasitica, infectées par l'hypovirus 1 (CHV 1). Cet hypovirus avait été montré capable de migrer rapidement dans le mycélium végétativement compatible (vc) de C. parasitica dans des chancres. Grâce un dispositif à 49 cellules (17,8×17,8 cm), la répartition spatiale et la fréquence des isolats blancs et pigmentés, et des GCV, ont étéétudiées dans des chancres superficiels chez les greffons, en dehors de la zone inoculée par les souches hypovirulentes. Quatre des six chancres étudiés contenaient des isolats blancs, dont la répartition spatiale était erratique chez trois d'entre eux. Les tests de compatibilité végétative, utilisant des isolats pigmentés et des colonies pigmentées mono-sporées d'isolats blancs, ont montré que la majorité des isolats blancs et des isolats colorés trouvés dans chacun des deux chancres analysés, était d'un seul type végétatif. Les cellules du dispositif, blanches ou pigmentées du même GCV, étaient fréquemment en contact, ce qui indique un mouvement incomplet de CHV1 dans un GCV. Neuf et dix GCV ont été trouvés dans les deux chancres et on avance l'hypothèse que de petites zones à GCV blancs dans chaque chancre peuvent être une source de transmission de CHV1 aux types végétatifs majoritaires. L'unique GCV majoritaire dans un des chancres n'était pas réparti au hasard (agrégé), mais il l'était dans l'autre chancre. Les variants blancs et pigmentés in vitro (secteurs) de C. parasitica, qui ressemblent aux variants blancs et pigmentés in vivo en contact spatial, étaient intermédiaires en hypovirulence et en virulence sur les châtaigniers américains, et respectivement positifs et négatifs pour le dsRNA. Un mouvement incomplet de CHV1 dans un GCV pourrait être la principale cause de la prévalence d'isolats pigmentés dans des chancres superficiels. Zusammenfassung Amerikanische Kastanien (Castanea dentata), die im Jahr 1980 von adulten überlebenden Exemplaren veredelt worden waren, wurden 1982 und 1983 mit vier unpigmentierten, hypovirulenten Stämmen von Cryphonectria parasitica aus Europa inokuliert, die mit dem Cryphonectria parasitica - hypovirus 1 (CHV 1) infiziert waren. Es war nachgewiesen, dass sich dieses Hypovirus rasch innerhalb des Myzels eines vc-Typs von C. parasitica in Krebsen ausbreiten konnte. Bei oberflächlichen Krebsen an veredelten Bäumen ausserhalb der mit dem hypovirulenten Stamm inokulierten Zone wurde auf einer 17,8×17,8 cm grossen Fläche (die in 49 Quadrate unterteilt wurde) die räumliche Verteilung und die Häufigkeit von unpigmentierten und pigmentierten Isolaten sowie der vc-Typen untersucht. Vier von sechs analysierten Krebsen enthielten weisse Isolate und drei davon zeigten zufällige Verteilungsmuster der Isolate (gemäss Joint-Count-Statistik). Vc-Tests mit pigmentierten Isolaten und pigmentierten Einzelsporkulturen von weissen Isolaten zeigten, dass die Mehrheit der weissen und der pigmentierten Isolate von zwei Krebsen zur gleichen vc-Gruppe gehörten. Weisse und pigmentierte Probepunkte mit dem gleichen vc-Typ waren häufig benachbart, was eine unvollständige Ausbreitung des CHV 1 innerhalb eines vc-Typs anzeigt. In den 2 Krebsen wurden 9 bzw. 10 vc-Typen nachgewiesen und es wird vermutet, dass kleine Bereiche mit weissem vc-Typ innerhalb eines Krebses als Reservoir für die Übertragung des Virus zu den dominanten vc-Typen fungieren können. Mit Hilfe der Joint-Count-Statistik wurde nachgewiesen, dass das räumliche Muster des einen, dominanten vc-Typs in einem Krebs nicht zufällig, sondern aggregiert war, während der andere Krebs ein zufälliges Verteilungsmuster der vc-Typen aufwies. Weisse und pigmentierte Varianten von C. parasitica, die in vitro auftraten (Sektoren), und die den weissen und pigmentierten Varianten sehr ähnlich sind, die in der Natur in räumlichem Kontakt zueinander auftreten, und die vegetativ kompatibel sind, zeigten in Feldversuchen auf C. sativa eine mittlere Hypovirulenz bzw. Virulenz. Ausserdem waren sie dsRNA positiv bzw. negativ. Die unvollständige Ausbreitung des CHV 1 innerhalb einer vc-Typs könnte das überwiegen pigmentierter Isolate in oberflächlichen Krebsen erklären. [source]

Two Genetically Distinct Populations of Colletotrichum gloeosporioides Penz.

JOURNAL OF PHYTOPATHOLOGY, Issue 3 2005
Causing Anthracnose Disease of Yam (Dioscorea spp.)
Abstract Variation within Colletotrichum gloeosporioides, the causal agent of yam anthracnose disease, is still poorly defined and this hinders breeding for resistance. Two morphotypes of C. gloeosporioides, designated slow-growing grey (SGG) and fast-growing salmon (FGS), are associated with anthracnose disease of yam in Nigeria. The morphotypes are distinguishable based on colony and conidial morphology, growth rate, virulence, as well as vegetative compatibility, but molecular differentiation of SGG and FGS strains is needed to facilitate epidemiological studies. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR)-amplified small subunit (18S) rDNA fragments, and microsatellite-primed PCR (MP-PCR) genomic fingerprinting were employed to provide a basis for molecular differentiation of the morphotypes. DGGE analysis revealed patterns that clearly differentiated isolates of the aggressive defoliating SGG from the moderately virulent non-defoliating FGS strains. Genetic analysis based on 52 MP-PCR markers revealed highly significant differentiation between the SGG and FGS populations on yam (GST = 0.22; Nei's genetic identity = 0.85; , = 0.28, P < 0.001), indicating that the SGG and FGS morphotypes represent genetically differentiated populations. The results of the molecular typing using DGGE and MP-PCR analyses were consistent with the disease phenotype caused by the two morphotypes. Consequently, these molecular techniques might be used, at least partly, to replace time-consuming virulence studies on yam. [source]

Vegetative Compatibility Among Isolates of Colletotrichum gloeosporioides from Yam (Dioscorea spp.) in Nigeria

Pathogenicity and Vegetative Compatibility of Fusarium oxysporum f. sp. phaseoli in Greece

Comparisons of Isolates of Fusarium avenaceum from White Lupin and Other Crops by Pathogenicity Tests, DNA Analyses and Vegetative Compatibility Tests

JOURNAL OF PHYTOPATHOLOGY, Issue 4 2000
K. Satyaprasad
Isolates of Fusarium avenaceum, mostly from crops of white lupin or wheat, were tested for pathogenicity on white lupin and wheat plants and compared by DNA tests and, in a limited study, vegetative compatibility. Most of the 80 isolates were pathogenic on both plant species after inoculation on shoot bases. Disease severity was greater at higher incubation temperatures that ranged from 15/10°C to 25/20°C (day/night temperatures). Isolates from lupin crops tended to be more pathogenic, on average, on lupins than on cereals. Polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis of the internal transcribed spacer region of the rDNA distinguished two groups of isolates that occurred in different proportions among isolates from lupins and cereal crops. Random amplified polymorphic DNA (RAPD)-PCR analyses indicated considerable genetic variation among isolates, but there was some similarity among groups of isolates from populations in the same field. Genetic diversity was confirmed by a high degree of vegetative incompatibility among 20 isolates using nitrate nonutilizing mutants. There were no relationships among pathogenicity, RFLP group, RAPD group and vegetative compatibility group. Zusammenfassung Fusarium-avenaceum -Isolate, die überwiegend von Weißier Lupine oder Weizen stammten, wurden hinsichtlich ihrer Pathogenität für Weißie Lupine und Weizenpflanzen getestet und durch DNA-Tests verglichen. In einer kleineren Studie wurde zudem ihre vegetative Kompatibilität geprüft. Die meisten der 80 Isolate waren nach Inokulation der Stengel-bzw. Halmbasis für beide Pflanzenarten pathogen. Bei hohen Inkubationstemperaturen im Bereich von 15/10°C bis 25/20°C (Tag/Nacht-Temperaturen) war der Befall stärker. Von Lupinen stammende Isolate waren im Durchschnitt stärker pathogen für Lupinen als für Getreide. Eine PCR-RFLP-Analyse der Internal-transcribed-spacer-Region der rDNA teilte die Isolate in zwei Gruppen, die bei den Isolaten von Lupinen und Getreide in verschiedenen Anteilen vertreten waren. RAPD-PCR-Analysen zeigten eine beträchtliche genetische Variation bei den Isolaten, aber auch gewisse Ähnlichkeiten bei den Isolatgruppen, die von Populationen im selben Feld stammten. Die genetische Diversität wurde auch durch ein hohes Ausmaßi an vegetativer Inkompatibilität bei 20 Isolaten deutlich; hier wurden Nitrat nicht verwertende Mutanten verwendet. Zwischen Pathogenität, RFLP-Gruppe, RAPD-Gruppe und vegetativer Kompatibilitätsgruppe bestanden keine Beziehungen. [source]

Cryphonectria parasitica vegetative compatibility type analysis of populations in south-western France and northern Spain

PLANT PATHOLOGY, Issue 3 2009
C. Robin
A comprehensive study of the population biology of Cryphonectria parasitica, the causal agent of chestnut blight, is required to understand the spread of the epidemic in Europe and its natural regulation by the Cryphonectria hypovirus-1 (CHV-1). With this objective in mind, the diversity in vegetative compatibility (vc) types and mating types of C. parasitica populations was assessed in 43 chestnut sites in western France and northern Spain. Isolates were sampled in three regions along the Pyrénées mountains (Hautes Pyrénées, Pyrénées Atlantiques and Navarra) and in two regions north of the Pyrénées (Landes and Dordogne). There were 61 vc types observed in 682 isolates sampled. Ninety-five isolates (14%) could not be assigned to any one of the previously known European vc types. The finding of 47 incompatible vc types confirmed that the genetics of vegetative compatibility could not be totally accounted for by six diallelic vic genes. The two idiomorphs of the mating type gene were detected in all regions, indicating that sexual reproduction could occur within and between vc types. In all regions except Dordogne, C. parasitica populations were dominated either by the vc type EU-66 or EU-72. Neither vc type has been reported elsewhere in Europe, which suggests that two different introductions of C. parasitica have occurred in the study area. In Dordogne, populations were dominated by EU-33 and EU-2, and to a lesser extent EU-66 and EU-72. The low diversity in vc types for most of the C. parasitica populations provides good opportunities for natural regulation in forest coppices and for biocontrol with CHV-1 in orchards. [source]

Distinguishing characteristics and vegetative compatibility of Colletotrichum kahawe in comparison with other related species from coffee

PLANT PATHOLOGY, Issue 2 2002
V. M. P. Varzea
On the basis of pathogenicity tests on green berries or hypocotyls of coffee and by morphological and biochemical characteristics in culture, 31 isolates of Colletotrichum were classified into C. kahawe (24 isolates), C. gloeosporioides (six isolates) or C. acutatum (one isolate). Within these groups of isolates, vegetative compatibility groups (VCGs) were determined by complementation tests with mutants in the nitrate assimilation pathway. There were distinct incompatibility barriers between the three species. Among the C. gloeosporioides group, the three isolates tested were self-compatible but incompatible with each other. Within C. kahawe, 18 isolates were self-compatible and only one main VCG was detected. However, partial compatibility in C. kahawe was also indicated by variation in the intensity of heterokaryon formation between different pairs of isolates and between different types of mutant. The existence of only one VCG in C. kahawe is consistent with the low level of variation found in previous work on DNA polymorphism. [source]