scholarly journals Characterization of California Isolates of Fusarium oxysporum f. sp. vasinfectum

Plant Disease ◽  
2005 ◽  
Vol 89 (4) ◽  
pp. 366-372 ◽  
Author(s):  
Y. Kim ◽  
R. B. Hutmacher ◽  
R. M. Davis

Thirty isolates of Fusarium oxysporum f. sp. vasinfectum from California, Australia, China, and the American Type Culture Collection were characterized by partial sequences of translational elongation factor (EF-1α), phosphate permase (PHO), and beta-tubulin (BT) genes, restriction digests of the intergenic spacer (IGS) region of nuclear rDNA, and pathogenicity tests. Based on phylogenetic analysis of combined sequences of EF-1α, PHO, and BT genes, California isolates represented four lineages. Lineage I contained race 3, lineage II contained races 1, 2, and 6, lineage III contained race 8, and lineage IV contained race 4. The Australian isolates formed a strongly supported independent clade. There were nine haplotypes based on restriction digests of the IGS region. In greenhouse pathogenicity tests with California isolates, those from the race 4 lineage were highly aggressive on certain Pima cotton (Gossypium barbadense) cultivars and less aggressive on Upland cotton (Gossypium hirsutum) cultivars. All isolates belonging to the other lineages caused relatively mild symptoms on both Pima and Upland cultivars. This is the first report of the occurrence of races 3, 4, and 8 in California.

2015 ◽  
Vol 105 (4) ◽  
pp. 525-532 ◽  
Author(s):  
Kazunori Sasaki ◽  
Katsuya Nakahara ◽  
Shuhei Tanaka ◽  
Masayoshi Shigyo ◽  
Shin-ichi Ito

Fusarium oxysporum f. sp. cepae causes Fusarium basal rot in onion (common onion) and Fusarium wilt in Welsh onion. Although these diseases have been detected in various areas in Japan, knowledge about the genetic and pathogenic variability of F. oxysporum f. sp. cepae is very limited. In this study, F. oxysporum f. sp. cepae was isolated from onion and Welsh onion grown in 12 locations in Japan, and a total of 55 F. oxysporum f. sp. cepae isolates (27 from onion and 28 from Welsh onion) were characterized based on their rDNA intergenic spacer (IGS) and translation elongation factor-1α (EF-1α) nucleotide sequences, vegetative compatibility groups (VCGs), and the presence of the SIX (secreted in xylem) homologs. Phylogenetic analysis of IGS sequences showed that these isolates were grouped into eight clades (A to H), and 20 onion isolates belonging to clade H were monophyletic and assigned to the same VCG. All the IGS-clade H isolates possessed homologs of SIX3, SIX5, and SIX7. The SIX3 homolog was located on a 4 Mb-sized chromosome in the IGS-clade H isolates. Pathogenicity tests using onion seedlings showed that all the isolates with high virulence were in the IGS-clade H. These results suggest that F. oxysporum f. sp. cepae isolates belonging to the IGS-clade H are genetically and pathogenically different from those belonging to the other IGS clades.


Pathogens ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 70 ◽  
Author(s):  
Sandra L. Carmona ◽  
Diana Burbano-David ◽  
Magda R. Gómez ◽  
Walter Lopez ◽  
Nelson Ceballos ◽  
...  

In Colombia, tomato production under protected conditions represents an important economic contribution to the agricultural sector. Fusarium wilt diseases, caused by pathogenic formae speciales of the soil-borne fungus Fusarium oxysporum Schltdl., cause significant yield losses in tomatoes throughout the world. Investigation of the F. oxysporum–tomato pathosystem in Colombia is required to develop appropriate alternative disease management. In this study, 120 fungal isolates were obtained from four different departments in the Central Andean Region in Colombia from tomato crops with symptoms of wilt disease. A molecular characterization of the fungal isolates was performed using the SIX1, SIX3, and SIX4 effector genes of Fusarium oxysporum f. sp. lycopersici W.C. Snyder & H.N. Hansen (Fol). Additionally, we developed a new specific marker to distinguish between Fusarium oxysporum f. sp. radicis-lycopersici Jarvis & Shoemaker (Forl) and Fol isolates. Furthermore, a phylogenetic analysis using the Translation Elongation Factor 1-alpha (EF1a) gene was performed with the collected isolates. Two isolates (named Fol59 and Fol-UDC10) were identified as Fol race 2, four isolates were identified as Forl, six isolates were identified as F. solani, and most of the isolates were grouped within the F. oxysporum species complex. The phylogenetic tree of EF1a showed that most of the isolates could potentially correspond to nonpathogenic strains of F. oxysporum. Additional pathogenicity assays carried out with Fol59 and Fol-UDC10 confirmed that both isolates were highly virulent strains. This study represents a contribution to the understanding of the local interaction between tomatoes and F. oxysporum in Colombia.


Plant Disease ◽  
2015 ◽  
Vol 99 (12) ◽  
pp. 1678-1688 ◽  
Author(s):  
Antonia Carlucci ◽  
Francesca Cibelli ◽  
Francesco Lops ◽  
Maria Luisa Raimondo

Botryosphaeriaceae spp. have a cosmopolitan distribution and a wide range of plant hosts. Over the last 15 years, worldwide, 21 species of this family have been associated with grapevine trunk diseases that cause cankers and dieback on grapevines. Here, we surveyed vineyards of Vitis vinifera ‘Lambrusco’, ‘Sangiovese’, and ‘Montepulciano’ in three areas of the Foggia province (Cerignola, Foggia, and San Severo) in southern Italy. Wood samples from grapevines showing general decline, dieback, cankers, and wood and foliar discoloration yielded 344 fungal isolates identified as Botryosphaeriaceae spp. A phylogenetic study combining internal transcribed spacer and translation elongation factor 1-α sequences of 60 representative isolates identified nine botryosphaeriaceous species: Botryosphaeria dothidea, Diplodia corticola, D. mutila, D. seriata, Dothiorella iberica, Do. sarmentorum, Lasiodiplodia citricola, L. theobromae, and Neofusicoccum parvum. Pathogenicity tests confirmed that all nine species cause canker and dieback of grapevines. However, this is the first report of L. citricola as causal agent of wood cankers and dieback of grapevine. To date, including L. citricola, there are 25 botryosphaeriaceous species associated with V. vinifera worldwide, of which 12 have been reported for grapevines in Italy.


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

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.


2020 ◽  
Vol 10 (9) ◽  
pp. 3261-3269
Author(s):  
Hannah C Halpern ◽  
Peng Qi ◽  
Robert C Kemerait ◽  
Marin T Brewer

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.


Plant Disease ◽  
2018 ◽  
Vol 102 (3) ◽  
pp. 552-560 ◽  
Author(s):  
Patrick Karangwa ◽  
Diane Mostert ◽  
Privat Ndayihanzamaso ◽  
Thomas Dubois ◽  
Björn Niere ◽  
...  

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.


1995 ◽  
Vol 46 (1) ◽  
pp. 167 ◽  
Author(s):  
KG Pegg ◽  
RG Shivas ◽  
NY Moore ◽  
S Bentley

A unique population of Fusarium oxysporum f. sp. cubense affecting Cavendish cv. Williams banana plants was characterized using vegetative compatibility, volatile production, RAPD-PCR analysis, pectic enzyme production and pathogenicity. The isolates were more like race 1 isolates than race 4 isolates, although they were capable of attacking Cavendish clones. The Carnarvon isolates did not belong to any of the vegetative compatibility groups (VCGs) known to occur in Australia or overseas; they belonged in the 'inodoraturn' volatile group; they had 29% genetic similarity to race 4 isolates and 76% similarity to race 1 isolates based on RAPD-PCR banding patterns; they belonged in the same pectic zymogram group as race 1 isolates and were virulent on 3-month-old Cavendish cv. Williams, Gros Michel and Pisang Gajih Merah plants in glasshouse tests.


2007 ◽  
Vol 97 (1) ◽  
pp. 87-98 ◽  
Author(s):  
Gladys Y. Mbofung ◽  
Soon Gyu Hong ◽  
Barry M. Pryor

Fusarium oxysporum f. sp. lactucae, causal agent of Fusarium wilt of lettuce, is a serious pathogen recently reported in Arizona. Sequence analysis of the mitochondrial small subunit (mtSSU), translation elongation factor 1-α (EF-1α) gene, and the nuclear ribosomal DNA intergenic spacer (IGS) region was conducted to resolve relationships among f. sp. lactucae isolates, F. oxysporum isolates from other hosts, and local non-pathogenic isolates. Analysis of mtSSU sequences provided limited phylogenetic resolution and did not differentiate the lactucae isolates from 13 other F. oxysporum isolates. Analysis of EF-1α sequences resulted in moderate resolution, grouping seven formae speciales with the lactucae isolates. Analysis of the IGS region revealed numerous sequence polymorphisms among F. oxysporum formae speciales consisting of insertions, deletions, and single nucleotide transitions and substitutions. Repeat sequence analysis revealed several duplicated subrepeat units that were distributed across much of the region. Based on analysis of the IGS sequence data, lactucae race 1 isolates resolved as a monophyletic group with three other formae speciales of F. oxysporum. In all analyses, lactucae race 2 isolates composed a separate lineage that was phylo-genetically distinct and distantly related to the lactucae race 1 isolates.


Plant Disease ◽  
2015 ◽  
Vol 99 (6) ◽  
pp. 780-787 ◽  
Author(s):  
M. C. Cañizares ◽  
C. Gómez-Lama ◽  
M. D. García-Pedrajas ◽  
E. Pérez-Artés

Fusarium wilt, caused by Fusarium oxysporum f. sp. dianthi, is the most important disease of carnation worldwide. Knowing the diversity of the F. oxysporum f. sp. dianthi population present in a carnation growing area is a key component of preventing dramatic losses in production. Sequence analyses of partial β-tubulin, translation elongation factor 1α genes, and the full-length ribosomal DNA intergenic spacer (IGS) were conducted to resolve phylogenetic relationships in a wide collection of Spanish F. oxysporum f. sp. dianthi isolates, along with some representatives from Italy. We found that, among the three different gene regions, the IGS sequence was the best choice to resolve phylogenetic relationships among F. oxysporum f. sp. dianthi isolates. The phylogenetic tree generated with the complete IGS region was the only one showing a clear clustering of isolates according to the molecular group (virulence grouping) and the vegetative compatibility group. In order to develop a more practical tool based on a shorter DNA sequence to quickly analyze diversity in F. oxysporum f. sp. dianthi populations, we examined IGS nucleotide alignments and identified a region of approximately 300 bp that accumulates enough “informative” changes to resolve intraspecific relationships and determine pathogenic variants in F. oxysporum f. sp. dianthi. Moreover, the “condensed” alignment of this short IGS region showing only the informative positions revealed the existence of virulence group-discriminating positions. In addition to clarifying the phylogenetic relationships among F. oxysporum f. sp. dianthi isolates of the recently described race groups by using multigene genealogies, we have developed simple tools for the phylogenetic analyses of F. oxysporum f. sp. dianthi populations and the determination of the molecular group of uncharacterized F. oxysporum f. sp. dianthi isolates.


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