scholarly journals Genetic Diversity of Fusarium oxysporum f. sp. cubense in East and Central Africa

Plant Disease ◽  
2018 ◽  
Vol 102 (3) ◽  
pp. 552-560 ◽  
Author(s):  
Patrick Karangwa ◽  
Diane Mostert ◽  
Privat Ndayihanzamaso ◽  
Thomas Dubois ◽  
Björn Niere ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Disease Management ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Management Practices ◽  
Management Strategies ◽  
Central Africa ◽  
Elongation Factor ◽  
Intergenic Spacer ◽  
Intergenic Spacer Region

Banana Fusarium wilt is a major production constraint globally and a significant threat to the livelihoods of millions of people in East and Central Africa (ECA). A proper understanding of the diversity and population dynamics of the causal agent, Fusarium oxysporum f. sp. cubense (Foc), could be useful for the development of sustainable disease management strategies for the pathogen. The current study investigated the diversity of Foc in ECA using vegetative compatibility group (VCG) analysis, PCR-RFLPs of the ribosomal DNA’s intergenic spacer region, as well as phylogenetic analysis of the elongation factor-1α gene. Six VCGs (0124, 0125, 0128, 01212, 01220, and 01222), which all belong to one lineage (Foc lineage VI), were widely distributed throughout the region. VCGs 0128 and 01220 are reported for the first time in Burundi, the Democratic Republic of Congo (DRC), Rwanda, Tanzania, and Uganda, while VCG 01212 is reported in the DRC and Rwanda. Isolates that did not belong to any of the known VCGs were identified as Foc lineage VI members by phylogenetic analysis and may represent novel VCGs. CAV 2734, a banana pathogen collected in Rwanda, clustered with nonpathogenic F. oxysporum isolates in lineage VIII. Results from this study will contribute significantly toward the implementation of banana Fusarium wilt disease management practices in the region, such as the restricted movement of infected planting material and the selective planting of resistant banana varieties.

scholarly journals The Population of Fusarium oxysporum f. sp. lactucae in California and Arizona

Plant Disease ◽  
2020 ◽  
Vol 104 (6) ◽  
pp. 1811-1816
Author(s):  
Kelley R. Paugh ◽  
Thomas R. Gordon
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Elongation Factor ◽  
Intergenic Spacer ◽  
Intermediate Step ◽  
Translation Elongation ◽  
Intergenic Spacer Region ◽  
Nit Mutants ◽  
Compatibility Group ◽  
Race 1

Fusarium wilt of lettuce, caused by Fusarium oxysporum f. sp. lactucae, is now found in all major lettuce producing regions in California and Arizona. The population structure of F. oxysporum f. sp. lactucae in California and Arizona was characterized based on somatic compatibility and sequences of the translation elongation factor 1-α gene (EF-1α) and rDNA intergenic spacer region (IGS). In this study, 170 isolates were tested for somatic compatibility based on heterokaryon formation, using complementary nitrate nonutilizing (nit) mutants. Five subgroups (A to E) of somatic compatibility group 0300 were identified. Isolates associated with the same subgroup had a strong complementation reaction, whereas reactions between isolates of different subgroups were weak or delayed. An isolate from the first known infestation of Fusarium wilt of lettuce in California was associated with subgroup A, which predominated among isolates in our collection. Isolates representative of each subgroup were confirmed to be associated with race 1, based on the reaction of differential lettuce cultivars. It is possible that somatic compatibility subgroups B to E of F. oxysporum f. sp. lactucae were derived from subgroup A, as a consequence of somatic mutations affecting compatibility. If so, subgroups of F. oxysporum f. sp. lactucae may represent an intermediate step in divergence that will lead to clearly separable compatibility groups. Sequences of EF-1α and IGS were both identical for 58 isolates of F. oxysporum f. sp. lactucae that represented all somatic compatibility subgroups and locations from which isolates were obtained, indicating that subgroups were derived from the same clonal lineage (VCG 0300).

scholarly journals Fusarium oxysporumf. sp.mori, a New Forma Specialis Causing Fusarium Wilt of Blackberry

Plant Disease ◽  
2017 ◽  
Vol 101 (12) ◽  
pp. 2066-2072 ◽  
Author(s):  
A. M. Pastrana ◽  
S. C. Kirkpatrick ◽  
M. Kong ◽  
J. C. Broome ◽  
T. R. Gordon
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Elongation Factor ◽  
Intergenic Spacer ◽  
Translation Elongation ◽  
Data Set ◽  
Tubulin Genes ◽  
Forma Specialis ◽  
Sequence Types ◽  
Strawberry Cultivars

Fusarium oxysporum has recently been identified as the cause of a wilt disease affecting blackberry in California and Mexico. Thirty-six isolates of F. oxysporum obtained from symptomatic blackberry plants in California and Mexico were comprised of nine distinct somatic compatibility groups (SCGs). Phylogenetic analysis of a concatenated data set, consisting of sequences of the translation elongation factor 1-α and β-tubulin genes and the intergenic spacer of the ribosomal DNA, identified nine three-locus sequence types, each of which corresponded to an SCG. Six SCGs were present only in California, two only in Mexico, and one in both California and Mexico. An isolate associated with the most common SCG in California was tested for pathogenicity on blueberry, raspberry, strawberry, and lettuce. All blueberry, raspberry, and lettuce plants that were inoculated remained healthy, but two of the five strawberry cultivars tested developed symptoms. The three strawberry cultivars that were resistant to the blackberry pathogen were also resistant to F. oxysporum f. sp. fragariae, the cause of Fusarium wilt of strawberry. We propose to designate strains of F. oxysporum that are pathogenic to blackberry as Fusarium oxysporum f. sp. mori forma specialis nov.

scholarly journals Evaluation of Nonpathogenic Fusarium oxysporum and Pseudomonas fluorescens for Panama Disease Control

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 951-959 ◽  
Author(s):  
A. Belgrove ◽  
C. Steinberg ◽  
A. Viljoen
Keyword(s):  
Fusarium Oxysporum ◽  
Pseudomonas Fluorescens ◽  
Fusarium Wilt ◽  
Intergenic Spacer ◽  
Polymorphism Analysis ◽  
Panama Disease ◽  
Intergenic Spacer Region ◽  
Soil Microbial ◽  
Fusarium Wilt Of Banana ◽  
Species Specific

Nonpathogenic Fusarium oxysporum endophytes from healthy banana roots were evaluated for their ability to reduce Fusarium wilt of banana (Panama disease). Isolates were identified morphologically and by using species-specific primers. Pathogenicity was confirmed by inoculating banana plantlets in the greenhouse. Nonpathogenic F. oxysporum isolates were grouped into 14 haplotype groups by polymerase chain reaction restriction fragment length polymorphism analysis of the intergenic spacer region, and representative isolates evaluated for biocontrol of F. oxysporum f. sp. cubense. In the greenhouse, 10 nonpathogenic F. oxysporum isolates were able to significantly reduce Fusarium wilt of banana. The isolate that protected banana plantlets best in the greenhouse, a nonpathogenic F. oxysporum from the root rhizosphere, and Pseudomonas fluorescens WCS 417 were then field tested. When the putative biological control organisms were tested in the field, neither the nonpathogenic F. oxysporum, P. fluorescens, nor combinations thereof reduced Fusarium wilt development significantly. A number of factors could contribute to the lack of field protection, including soil microbial and chemical composition and reduced survival of biocontrol organisms in banana roots. A lack of knowledge regarding the etiology of Fusarium wilt of ‘Cavendish’ banana in the subtropics and the effect of F. oxysporum f. sp. cubense race and banana cultivar in protection of banana by biocontrol organisms should be further investigated.

scholarly journals Genetic Diversity and Population Structure of Races of Fusarium oxysporum Causing Cotton Wilt

2020 ◽  
Vol 10 (9) ◽  
pp. 3261-3269
Author(s):  
Hannah C Halpern ◽  
Peng Qi ◽  
Robert C Kemerait ◽  
Marin T Brewer
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Fusarium Oxysporum ◽  
Principal Components ◽  
Phylogenetic Trees ◽  
Elongation Factor ◽  
Intergenic Spacer ◽  
Pathogenic Fungi ◽  
The United States ◽  
Intergenic Spacer Region

Abstract To better understand the evolution of virulence we are interested in identifying the genetic basis of this trait in pathogenic fungi and in developing tools for the rapid characterization of variation in virulence among populations associated with epidemics. Fusarium oxysporum f. sp. vasinfectum (FOV) is a haploid fungus that causes devastating outbreaks of Fusarium wilt of cotton wherever it is grown. In the United States, six nominal races and eleven genotypes of FOV have been characterized based on the translation elongation factor (EF-1α) gene and intergenic spacer region (IGS), but it is unclear how race or genotype based on these regions relates to population structure or virulence. We used genotyping-by-sequencing to identify SNPs and determine genetic diversity and population structure among 86 diverse FOV isolates. Six individuals of Fusarium oxysporum closely related to FOV were genotyped and included in some analyses. Between 193 and 354 SNPs were identified and included in the analyses depending on the pipeline and filtering criteria used. Phylogenetic trees, minimum spanning networks (MSNs), principal components analysis (PCA), and discriminant analysis of principal components (DAPC) demonstrated that races and genotypes of FOV are generally not structured by EF-1α genotype, nor are they monophyletic groups with the exception of race 4 isolates, which are distinct. Furthermore, DAPC identified between 11 and 14 genetically distinct clusters of FOV, whereas only eight EF-1α genotypes were represented among isolates; suggesting that FOV, especially isolates within the widely distributed and common race 1 genotype, is more genetically diverse than currently recognized.

scholarly journals Phylogenetic and Biological Characterization of Fusarium oxysporum Isolates Associated with Onion in South Africa

Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1250-1261 ◽  
Author(s):  
Michael J. Southwood ◽  
Altus Viljoen ◽  
Lizel Mostert ◽  
Lindy J. Rose ◽  
Adéle McLeod
Keyword(s):  
South Africa ◽  
Fusarium Oxysporum ◽  
Mating Type ◽  
Elongation Factor ◽  
Intergenic Spacer ◽  
Small Subunit ◽  
Limited Information ◽  
Vegetative Compatibility Groups ◽  
Intergenic Spacer Region ◽  
Fusarium Basal Rot

Fusarium oxysporum f. sp. cepae causes Fusarium basal rot of onion, a disease of worldwide importance. Limited information is available on the phylogenetic diversity, vegetative compatibility groups (VCGs), mating type idiomorphs, and virulence of F. oxysporum isolates associated with onion. Therefore, these characteristics were investigated in 19 F. oxysporum f. sp. cepae isolates from Colorado, 27 F. oxysporum f. sp. cepae and 33 F. oxysporum isolates nonpathogenic to onion from South Africa. Six F. oxysporum f. sp. cepae VCGs (0421 to 0426) were identified, of which three were new. The dominant VCGs in Colorado and South Africa were VCG 0421 (47% of isolates) and VCG 0425 (74%), respectively. VCG 0423 was the only VCG that was shared between the two regions. Molecular phylogenies (intergenic spacer region of the rDNA, elongation factor 1α, and mitochondrial small-subunit) confirmed the polyphyletic nature of F. oxysporum f. sp. cepae and showed that some F. oxysporum f. sp. cepae and nonpathogenic F. oxysporum isolates were genetically related. Most F. oxysporum f. sp. cepae isolates clustered into two distinct, well-supported clades. The largest clade only contained highly virulent isolates, including the two main VCGs (0421 and 0425), whereas the basal clade mostly contained moderately virulent isolates. These groupings along with the VCG data provide an important basis for selection of isolates for use in breeding programs, and for the development of molecular makers to identify VCGs. Mating type genotyping revealed the distribution of both mating type (MAT1-1 and MAT1-2) idiomorphs across phylogenetic clades, and the fact that several isolates contained both idiomorphs.

scholarly journals The development of a multiplex PCR assay for the detection of Fusarium oxysporum f. sp. cubense lineage VI strains in East and Central Africa

2020 ◽  
Vol 158 (2) ◽  
pp. 495-509 ◽  
Author(s):  
P. Ndayihanzamaso ◽  
P. Karangwa ◽  
D. Mostert ◽  
G. Mahuku ◽  
G. Blomme ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Multiplex Pcr ◽  
Fusarium Wilt ◽  
Central Africa ◽  
East African ◽  
Pcr Assay ◽  
Vegetative Compatibility Groups ◽  
Worldwide Population ◽  
Multiplex Pcr Assay ◽  
Disease Free

Abstract Banana is a staple food and cash crop grown in East and Central Africa (ECA). The main banana varieties grown in ECA are the East African highland bananas (EAHB), although dessert/beer bananas such as Sukari Ndizi, Kayinja (Pisang Awak) and Gros Michel are also produced due to their high value at local markets. The Fusarium wilt fungus Fusarium oxysporum f. sp. cubense (Foc) causes disease of susceptible dessert/beer bananas, which significantly reduces yields. Banana Fusarium wilt is managed by excluding the pathogen from disease-free areas and by planting disease-resistant varieties in infested fields. Six phylogenetically closely-related vegetative compatibility groups (VCGs) of Foc, VCGs 0124, 0125, 0128, 01212, 01220 and 01222 are present in ECA, which all group together in Foc Lineage VI. Rapid and accurate detection of Foc Lineage VI strains is thus important to prevent its spread to disease-free areas. In this study, molecular markers specific to Foc Lineage VI were therefore developed. Primer sets were then combined in a multiplex PCR assay, and validated on a worldwide population of 623 known Foc isolates, other formae speciales and non-pathogenic Fusarium oxysporum isolates. The Foc Lineage VI multiplex PCR was used to identify Foc isolates collected in banana fields at five locations in Uganda and Tanzania. Foc Lineage VI DNA was detected at a concentration as low as 0.1 ng/μl, both in the absence and presence of banana DNA, and can therefore be used as an accurate diagnostic tool for Foc Lineage VI strains.

Isolation and Phylogenetic Analysis of Avian Mycoplasmas from Poultry Affected with Respiratory Infections in India

2020 ◽  
Author(s):  
Y. Singh ◽  
P. Tomar ◽  
N. K. Mahajan ◽  
N. Jindal
Keyword(s):  
Phylogenetic Analysis ◽  
Broiler Chicken ◽  
Respiratory Infections ◽  
Intergenic Spacer ◽  
Mycoplasma Gallisepticum ◽  
Epidemiological Investigation ◽  
Wild Type ◽  
Tissue Samples ◽  
Growth Inhibition Test ◽  
Intergenic Spacer Region

Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) are the two most pathogenic avian mycoplasmas. In the present study, examination of 92 pooled tissue samples from broiler chicken of 92 different poultry flocks of Haryana (India) exhibiting respiratory infections resulted in isolation of 13 (14%) Mollicutes. Based on biochemical reactions, growth inhibition test, PCR and/or sequencing, 8 (8.6%) isolates could be characterized as MG, 1 (1.08%) as MS, 3 (3.24%) as M. gallinarum and 1 (1.08%) as Acholeplasma laidlawii. The phylogenetic analysis using Intergenic spacer region (IGSR) of these MG isolates revealed that they clustered with USA strain whereas the vaccine strains were in different clade. Single locus sequence typing (SLST) revealed considerable nucleotides variation between 8 MG isolates and vaccine strains. Conclusively, Sequencing of IGSR region of MG can be used as a valuable epidemiological investigation tool for the differentiation of wild-type MG strains from vaccine strains.

scholarly journals First Report of Fusarium Wilt of Paper Flower (Bougainvillea glabra) Caused by Fusarium oxysporum in Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 483-483 ◽  
Author(s):  
G. Polizzi ◽  
D. Aiello ◽  
V. Guarnaccia ◽  
A. Vitale ◽  
G. Perrone ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Disease Incidence ◽  
Elongation Factor ◽  
Gene Sequences ◽  
Single Spore ◽  
Potential Threat ◽  
First Report ◽  
Potted Plants ◽  
Bougainvillea Glabra

Paper flower (Bougainvillea glabra Choisy), native to Brazil, is the most widely and intensively cultivated species of bougainvillea as a potted plant in Sicily (Italy). During 2008 and 2009, a wilting of vegetatively produced B. glabra cv. Sanderiana was observed in several nurseries in eastern Sicily (Catania and Messina provinces). Disease incidence was higher (~10 to 30%) in the tree-shaped potted plants (standards). Occasionally, wilting was detected on plants that were not tree shaped. Internally, symptomatic plants showed conspicuous vascular orange discoloration from the crown to the canopy. Diseased crown and stem tissues were surface disinfested for 30 s in 1% NaOCl, rinsed in sterile water, plated on potato dextrose agar (PDA) amended with 100 mg/liter of streptomycin sulfate, and incubated at 25°C. A Fusarium sp. was consistently isolated from affected plant tissue. Colonies with light purple or purple mycelia and violet reverse colony colors developed after 10 days. On carnation leaf agar, single-spore isolates produced microconidia in false heads on short monophialides, macroconidia that were 3-septate with a pedicellate base, and solitary and double-celled or aggregate chlamydospores. A PCR assay was conducted on two representative strains (DISTEF-BGS1 and DISTEF-BGS2) by analyzing sequences of the parzial translation elongation factor alpha gene (TEF-1α) and CaM gene (coding calmodulin protein). The primers used are previously used by O'Donnell et al. (1,2). Calmodulin sequences of BGS1 and BGS2 strains (GenBank Nos. FN645740 and FN645741, respectively) exhibited 99% homology with Fusarium oxysporum strain ITEM 2367 (GenBank No. AJ560774), and have homology of 99.6% between them. TEF-1 gene sequences of BGS1 (GenBank No. FN645739) exhibited an identity of 100% to F. oxysporum f. sp. lycopersici MUCL 22544 GenBank No. EF056785.1) and TEF-1α gene sequences of BGS2 (GenBank No. FN655742) exhibited an identity of 100% to F. oxysporum strain NRRL 45954 (GenBank No. FJ985431.1), whereas the homology between the two strains is 98.5%. Both PCR approaches established the identity of the isolates to the F. oxysporum Schlechtend:Fr (1,2). Pathogenicity tests were performed by placing 1-cm2 plugs of PDA from 10-day-old mycelial cultures near the crown on 40 potted, healthy, 6-month-old cuttings of paper flower. Twenty plants for each isolate were used. The same number of plants served as noninoculated controls. All plants were enclosed for 5 days in plastic bags and placed in a growth chamber at 24 ± 1°C. Plants were then moved to a greenhouse where temperatures ranged from 24 to 26°C. Symptoms identical to those observed in nurseries developed 1 month after inoculation with both strains. Crown and stem orange discoloration was detected in all inoculated plants after 2 months. Control plants remained symptomless. F. oxysporum was consistently reisolated from symptomatic tissues and identified as previously described. To our knowledge, F. oxysporum was previously reported on paper flower in Ghana (3). However, this is the first demonstration of the pathogenicity of F. oxysporum on paper flower and it is the first report in Europe of the disease. The presence of Fusarium wilt in Sicily is a potential threat to paper flower production in nurseries. References: (1) K. O'Donnell et al. Proc. Natl. Acad. Sci. USA 95:2044, 1998. (2) K. O'Donnell et al. Mycoscience 41:61, 2000. (3) P. Spaulding. USDA Agric. Handb. 197:1, 1961.

scholarly journals Genetic and Morphological Variability among the Isolates of Fusarium oxysporum f. sp. lentis causing Wilt of Lentil

2021 ◽  
Author(s):  
Anshul Arya ◽  
Sujata Singh ◽  
K.P.S. Kushwaha ◽  
Yogita Bohra ◽  
Arun Kushwaha ◽  
...  
Keyword(s):  
Disease Management ◽  
Fusarium Oxysporum ◽  
Morphological Variability ◽  
Management Strategies ◽  
Uttar Pradesh ◽  
Morphological Diversity ◽  
Population Diversity ◽  
Yield Losses ◽  
Diversity Methods ◽  
Ssr Primers

Background: Lentil wilt is one of the most important diseases of lentil directly contributing to the yield losses of the crop. It is caused by Fusarium oxysporum f. sp. lentis which shows the great genetic and morphological diversity. Methods: Present investigation was conducted during 2017-2019 with 22 isolates of the pathogen, collected from lentil grown areas of Uttarakhand and Uttar Pradesh to explore genetic and morphological variability employing eight ISSR and five SSR primers. Result: The isolates showed huge morphological variability based on the color, pigmentation and shape of conidia. Study on molecular variability revealed the versatility in the genome of different isolates of pathogen. The diversity among the isolates of pathogens collected from Uttarakhand and Uttar Pradesh was also evident. Generated work on genetic and morphological variability and the population diversity among the different isolates of the pathogen impact on developing ideal disease management strategies.

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