Fusarium verticillioides from sugarcane, vegetative compatibility groups and pathogenicity

Sugarcane plant samples affected by the disease pokkah boeng were collected from the major sugarcane producing areas in Iran. Fifty isolates of Fusarium verticillioides were recovered from diseased sugarcanes. Results of pathogenicity tests revealed that all isolates were pathogenic to sugarcane. Four hundred and eighty-five nitrate non-utilising mutants were generated from F. verticillioides isolates. Media used for nit mutant generation included potato dextrose agar, minimal medium and Czapeck agar amended with 1.8%, 2%, 2.5%, and 3% potassium chlorate. Nit mutants were divided into three phenotypic (nit1, nit3, and nitM) classes based on their growth on different nitrogen sources in the culture media. Among the isolates tested, 280, 115 and 90 nit1, nit3, and nit M were generated, respectively. Nit mutants were used to force the heterokaryon formation to determine the distribution of VCGs and their relation to pathogenicity and geographic origin. Forty-eight VCGs of F. verticillioides were isolated from sugarcane. Forty-six of the VCGs were represented by a single isolate, whereas the remaining two comprised two isolates. None of the VCGs was common.

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Genetic variability and vegetative compatibility in Aspergillus niger isolated from various food substances in Benin City Nigeria

Journal of Applied Sciences and Environmental Management ◽

10.4314/jasem.v24i12.23 ◽

2021 ◽

Vol 24 (12) ◽

pp. 2161-2165

Author(s):

L. Eboigbe ◽

M.O. Omoregbe

Keyword(s):

Aspergillus Niger ◽

Minimal Medium ◽

Genetic Recombination ◽

Potato Dextrose Agar ◽

Vegetative Compatibility ◽

Complementation Test ◽

Vegetative Compatibility Groups ◽

Benin City ◽

Nit Mutants ◽

Mutant Strains

In this investigation, Aspergillus niger isolated from eight food substances, have been classified based on the absence of heterokaryon formation. The size of their sporangia were differentiated, the wild and mutant strains were subjected to vegetative compatibility tests in order to group them into different vegetative compatibility groups (VCGs) which include VCG-1, VCG-2, VCG-3 and VCG-4. The strains were further tested for the possible formation of a stable heterokaryon using nit mutants generated on potato dextrose agar (PDA) containing 2.5% chlorate (KClO3), represented as PDC. Based on the vegetative compatibility groups, nit mutants were paired on a minimal medium (MM) for complementation test. Interestingly, there was compatibility with mycelia showing anastomoses but without the formation of heterokaryon. The vegetative compatibility groups suggested four genotypes and polymorphism in the het loci. A population study for detailed genotyping is suggested in order to unravel the genetic recombination in A. niger.

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Vegetative Compatibility Groups of Fusarium oxysporum f. sp. cepae from Onion in Colorado

Plant Disease ◽

10.1094/pdis.2002.86.6.606 ◽

2002 ◽

Vol 86 (6) ◽

pp. 606-610 ◽

Cited By ~ 20

Author(s):

C. E. Swift ◽

E. R. Wickliffe ◽

H. F. Schwartz

Keyword(s):

Fusarium Oxysporum ◽

Minimal Medium ◽

Potato Dextrose Agar ◽

Vegetative Compatibility ◽

Potassium Chlorate ◽

Vegetative Compatibility Groups ◽

Breeding For Resistance ◽

Nit Mutants ◽

Northern Regions

Nineteen isolates of Fusarium oxysporum f. sp. cepae recovered from diseased onions growing in the western, southern, and northern regions of Colorado were placed into vegetative compatibility groups (VCGs) based on pairing of complementary mutants. Pathogenic isolates from these regions were cultured on variations of potassium chlorate (1.5 or 3.0%) mutation media, potato dextrose agar (PDA), and minimal medium (MM) supplemented with L-asparagine and L-threonine. Chlorate PDA and 3% chlorate MM with L-threonine did not generate the nitrate nonutilizing (nit) mutants required, while MM with L-asparagine (1.5 and 3% chlorate) and MM with L-threonine (1.5% chlorate) generated complementary nit mutants required for compatibility pairings. Five VCGs of F. oxysporum cepae were identified. One VCG was present in all three regions of Colorado examined. Four VCGs were restricted to either western or eastern Colorado. Additional sampling and evaluation of a more diverse collection of F. oxysporum cepae isolates from other regions of onion production is needed to determine the diversity of this pathogen. Such information could assist in breeding for resistance to F. oxysporum cepae.

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The Influence of Some Sources of Nitrogen on the Growth and Development of the Phomopsis Incarcerata Pathogen (SACC.) Hohnel

Revista de Chimie ◽

10.37358/rc.70.19.11.7691 ◽

2019 ◽

Vol 70 (11) ◽

pp. 4000-4002

Keyword(s):

Growth And Development ◽

Culture Media ◽

Nitrogen Sources ◽

Potato Dextrose Agar ◽

Malt Extract ◽

Beta Alanine ◽

Ph Values ◽

Ecological Aspects ◽

Optimum Ph

Phomopsis incarcerata, known as the pathogen which caused the dieback of Rosa branches was detected in many orchards in Romania. Our investigations have approached a series of bio-ecological aspects of this pathogen: isolation, purification and obtaining the pathogen; determination and identification of the pathogen; establishing in vitro parameters of fungal development (nitrogen source). The isolate used in this study was obtained from Rosa spp. branches and was cultivated on three culture media: potato dextrose agar (PDA), malt extract agar and water agar which included five amino-acids: cysteine, glycine, beta-alanine, leucine and tryptophan. Leucine and glycine were favorable for the dynamics of the fungus.When the fungus grew on water agar, the sporulation was completely inhibited. The optimum pH values for the growth and creation of the Phomopsis incarcerata are in the range of 4.4-7, so weak to neutral acid. Keywords: Phomopsis, nitrogen sources, Rosa, pathogen

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

Phytopathology ◽

10.1094/phyto.2002.92.8.827 ◽

2002 ◽

Vol 92 (8) ◽

pp. 827-832 ◽

Cited By ~ 41

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.

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Variability in Fusarium oxysporum f.sp. cubense

Canadian Journal of Botany ◽

10.1139/b90-173 ◽

1990 ◽

Vol 68 (6) ◽

pp. 1357-1363 ◽

Cited By ~ 21

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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Pathogenicity and diversity of vegetative compatibility of Fusarium verticillioides

Zbornik Matice srpske za prirodne nauke ◽

10.2298/zmspn0713103k ◽

2007 ◽

pp. 103-111 ◽

Cited By ~ 3

Author(s):

Vesna Krnjaja ◽

Jelena Levic ◽

Slavica Stankovic ◽

Zorica Tomic

Keyword(s):

Genetic Diversity ◽

Disease Severity ◽

Fusarium Verticillioides ◽

Dry Weight ◽

Vegetative Compatibility ◽

High Genetic Diversity ◽

Plant Vigour ◽

Vegetative Compatibility Groups ◽

Nit Mutants ◽

High Degree

Pathogenicity of 10 Fusarium verticillioides isolates, originated from grain of wheat (five isolates) and maize (five isolates), were studied under greenhouse conditions. Based on different parameters of the pathogenicity estimate (a scale for % of nonemerged plants, % of survived plants, plant vigour - the growth and dry weight of roots and epicotyls and disease severity) it was determined that all F. verticillioides isolates expressed a different degree of pathogenicity. According to % of nonemerged plants six three and one F. verticillioides isolates expressed low, moderate and high degree of pathogenicity, respectively. All F. verticillioides isolates reduced the plant survival rate and vigour, while the disease severity ranged from 2.0 to 3.54. Two types of nit mutants, nit1 and NitM, were obtained by the use of the method of vegetative compatibility. The frequency of nit1 mutants was greater (58.79%) than the frequency of NitM mutants (5.77%). A total of 10 vegetative compatibility groups (VCGs) of F. verticillioides were established in the complementation tests. These results point out to a high genetic diversity of F. verticillioides population.

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Vegetative Compatibility Groups in Cercospora kikuchii, the Causal Agent of Cercospora Leaf Blight and Purple Seed Stain in Soybean

Phytopathology ◽

10.1094/phyto-95-0257 ◽

2005 ◽

Vol 95 (3) ◽

pp. 257-261 ◽

Cited By ~ 18

Author(s):

G. Cai ◽

R. W. Schneider

Keyword(s):

Leaf Blight ◽

Vegetative Compatibility ◽

The Other ◽

Wild Type ◽

Cercospora Kikuchii ◽

Vegetative Compatibility Groups ◽

Nit Mutants ◽

Pathogenicity Tests ◽

Soybean Plants ◽

Soybean Leaves

Nitrogen nonutilizing (Nit) mutants were used to assess vegetative compatibility of 58 isolates of Cercospora kikuchii, 55 of which were isolated from soybean plants in Louisiana. Two isolates were vegetatively self-incompatible. Of 56 self-compatible isolates, 16 were assigned to six multimember vegetative compatibility groups (VCGs), 01 to 06, with 2 or 3 isolates in each VCG. The other 40 isolates each belonged to a distinct VCG. All six multimember VCGs contained isolates from different soy bean cultivars, and three included isolates from different locations. Only one of six multimember VCGs included isolates both from soybean leaves and seed, while the other five included isolates from only leaves or seed. The likelihood of tissue specificity or preference was discussed. All isolates and tested Nit mutants produced cercosporin on potato dextrose agar under light. Significantly different amounts of cercosporin were produced among wild-type isolates, and two Nit mutants produced significantly more cercosporin than their wild-type counterparts. All isolates produced typical Cercospora leaf blight symptoms on soybean plants in greenhouse pathogenicity tests.

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Evaluation of the growth and sporulation of different entomopathogenic fungi in different liquid and solid media at varied concentrations

International Journal of Bioassays ◽

10.21746/ijbio.2017.08.003 ◽

2017 ◽

Vol 6 (8) ◽

pp. 5459

Author(s):

Chandra Teja K. ◽

Rahman S. J.

Keyword(s):

Entomopathogenic Fungi ◽

Large Scale ◽

Insect Pests ◽

Culture Media ◽

Virulent Strain ◽

Carbon Sources ◽

Nitrogen Sources ◽

Maximum Growth ◽

Nutritional Requirements ◽

Virulent Strains

Entomopathogenic fungi like Beauveria bassiana, Metarhizium anisopliae and Lecanicillium lecanii are used in biological control of agricultural insect pests. Their specific mode of action makes them an effective alternative to the chemical Insecticides. Virulent strains of Entomopathogenic fungi are effectively formulated and used as bio-insecticides world-wide. Amenable and economical multiplication of a virulent strain in a large scale is important for them to be useful in the field. Culture media plays a major role in the large-scale multiplication of virulent strains of Entomopathogens. Different substrates and media components are being used for this purpose. Yet, each strain differs in its nutritional requirements for the maximum growth and hence it is necessary to standardize the right components and their optimum concentrations in the culture media for a given strain of Entomopathogen. In the current study, three different nitrogen sources and two different carbon sources were tried to standardize the mass multiplication media for seven test isolates of Entomopathogenic fungi. A study was also conducted to determine the ideal grain media for the optimum conidial yields of the test isolates. Yeast extract was found to be the best Nitrogen source for the isolates. The isolates tested, differed in their nutritional requirements and showed variation in the best nitrogen and carbon sources necessary for their growth. Variation was also found in the optimum concentration of both the ingredients for the growth and sporulation of the isolates. In the solid-state fermentation study, rice was found to be the best grain for the growth of most of the fungi followed by barley. The significance of such a study in the development of an effective Myco-insecticide is vital and can be successfully employed in agriculture is discussed.

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Outbreak of Leaf Spot and Fruit Rot in Florida Strawberry Caused by Neopestalotiopsis spp.

Plant Disease ◽

10.1094/pdis-06-20-1290-re ◽

2021 ◽

pp. PDIS-06-20-1290

Author(s):

Juliana S. Baggio ◽

Bruna B. Forcelini ◽

Nan-Yi Wang ◽

Rafaela G. Ruschel ◽

James C. Mertely ◽

...

Keyword(s):

Internal Transcribed Spacer ◽

Phylogenetic Analyses ◽

Morphological Characteristics ◽

Taxonomic Status ◽

Spore Production ◽

Potato Dextrose Agar ◽

Fruit Rot ◽

Low Genetic Diversity ◽

Pathogenicity Tests ◽

A New Species

Pestalotiopsis-like species have been reported affecting strawberry worldwide. Recently, severe and unprecedented outbreaks have been reported in Florida commercial fields where leaf, fruit, petiole, crown, and root symptoms were observed, and yield was severely affected. The taxonomic status of the fungus is confusing because it has gone through multiple reclassifications over the years. Morphological characteristics, phylogenetic analyses, and pathogenicity tests were evaluated for strawberry isolates recovered from diseased plants in Florida. Phylogenetic analyses derived from the combined internal transcribed spacer, β-tub, and tef1 regions demonstrated that although there was low genetic diversity among the strawberry isolates, there was a clear separation of the isolates in two groups. The first group included isolates recovered over a period of several years, which was identified as Neopestalotiopsis rosae. Most isolates recovered during the recent outbreaks were genetically different and may belong to a new species. On potato dextrose agar, both groups produced white, circular, and cottony colonies. From the bottom, colonies were white to pale yellow for Neopestalotiopsis sp. and pale luteous to orange for N. rosae. Spores for both groups were five-celled with three median versicolored cells. Mycelial growth and spore production were higher for the new Neopestalotiopsis sp. isolates. Isolates from both groups were pathogenic to strawberry roots and crowns. However, the new Neopestalotiopsis sp. proved more aggressive in fruit and leaf inoculation tests, confirming observations from the recent outbreaks in commercial strawberry fields in Florida.

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

Phytopathology ◽

10.1094/phyto-98-11-1205 ◽

2008 ◽

Vol 98 (11) ◽

pp. 1205-1211 ◽

Cited By ~ 6

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.

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