scholarly journals Pathogenic and Genetic Variation in the Japanese Strains of Fusarium oxysporum f. sp. melonis

1998 ◽  
Vol 88 (8) ◽  
pp. 804-810 ◽  
Author(s):  
Fumio Namiki ◽  
Toshiki Shiomi ◽  
Kazufumi Nishi ◽  
Tsuruo Kayamura ◽  
Takashi Tsuge
Keyword(s):  
Genetic Variation ◽  
Fusarium Oxysporum ◽  
Dna Sequences ◽  
Nuclear Markers ◽  
Oriental Melon ◽  
Genetic Groups ◽  
Pathogenic Variation ◽  
Pathogenicity Tests ◽  
Race 2 ◽  
Single Cluster

Pathogenic variation among 41 Japanese strains of Fusarium oxysporum f. sp. melonis was analyzed by pathogenicity tests with muskmelon, oriental melon, and oriental pickling melon cultivars. Based on pathogenicity to muskmelon cvs. Amus and Ohi and oriental melon cv. Ogon 9, 41 strains were divided into 3 groups that corresponded completely to Risser's races 0, 2, and 1,2y. To further characterize pathogenic variation within the forma specialis and races, strains were assayed for pathogenicity to 42 additional muskmelon, oriental melon, and oriental pickling melon cultivars. All strains of race 1,2y were pathogenic to all cultivars tested. Strains of race 0 were divided into six variants based on differences in pathogenicity to three muskmelon cultivars; strains of race 2 also were classified into six variants based on differences in pathogenicity to two muskmelon cultivars and one oriental melon cultivar. Genetic variation among strains was analyzed by DNA fingerprinting with four repetitive DNA sequences: FOLR1 to FOLR4. Thirty-six fingerprint types were detected among forty-one strains by pooling results of fingerprinting with four probes. Cluster analysis showed distinct genetic groups correlated with races: the fingerprint types detected in each of races 2 and 1,2y were grouped into a single cluster, and two distinct genetic groups were found in race 0. However, pathogenic variation detected within races 0 and 2 could not be differentiated based on the nuclear markers examined.

scholarly journals Genetic Diversity of Fusarium oxysporum f. sp. dianthi in Southern Spain

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Raúl Castaño ◽  
Barbara Scherm ◽  
Manuel Avilés
Keyword(s):  
Fusarium Oxysporum ◽  
Phylogenetic Analyses ◽  
Gene Sequencing ◽  
Southern Spain ◽  
Specific Pcr ◽  
Rapd Pcr ◽  
Race 1 ◽  
Pathogenicity Tests ◽  
Specific Band ◽  
Race 2

The diversity of races and prevalence of pathogenic populations of Fusarium oxysporum f. sp. dianthi (Fod) were surveyed in an area in southern Spain. From 54 farms, 132 isolates were collected from wilted carnation plants. Isolates were characterized by RAPD-PCR, DNA sequence analysis of the TEF1-α gene, and race-specific molecular markers. Selected isolates from RAPD groups were phenotypically evaluated by pathogenicity tests. Data analysis showed that Fod race 2 was the most frequent and prevalent race in the study area, followed by race 1/8. Moreover, phylogenetic analyses showed similar results, which were different to those of the race-specific PCR assays. It was concluded that (i) seven isolates were not classified in groups where Fod testers were clustered; even they showed different results when race-specific markers were used, (ii) ten isolates with retarded race 1 or race 8 specific band were characterized as F. proliferatum by TEF1-α gene sequencing and clustered into an outgroup, and (iii) six isolates failed to generate an amplification signal using race-specific markers. Furthermore, three of them were grouped close to race 2 tester according to the phylogenetic analyses, showing the same differential pathogenicity as race 2. This may indicate a Fod race 2 subgroup in this region.

Comparing vegetative compatibility and protein banding patterns for identification of Fusarium oxysporum f.sp. apii race 2

1991 ◽  
Vol 37 (9) ◽  
pp. 669-674 ◽  
Author(s):  
K. F. Toth ◽  
M. L. Lacy
Keyword(s):  
Fusarium Oxysporum ◽  
Polyacrylamide Gel Electrophoresis ◽  
Vegetative Compatibility ◽  
Wild Type ◽  
Banding Patterns ◽  
Formae Speciales ◽  
Compatibility Group ◽  
Race 1 ◽  
Pathogenicity Tests ◽  
Race 2

Vegetative compatibility grouping and electrophoretic separation of total proteins were compared as possible techniques for identifying isolates of Fusarium oxysporum f.sp. apii race 2, the cause of fusarium yellows of celery. Vegetative compatibility grouping was determined by pairing chlorate-tolerant, nitrate-nonutilizing mutants on a minimal medium containing nitrate as the sole nitrogen source. Heterokaryon formation, which resulted in wild-type growth, occurred only between mutants from vegetatively compatible isolates. All isolates of F. oxysporum f.sp. apii race 2 examined were placed within a unique vegetative compatibility group that excluded F. oxysporum f.sp. apii race 1 and the 11 other formae speciales of F. oxysporum tested. Few differences were observed in protein banding patterns among isolates of F. oxysporum f.sp. apii race 2, F. oxysporum f.sp. apii race 1, 11 other formae speciales of F. oxysporum, and 2 formae speciales of F. solani on 12% polyacrylamide gels. No banding pattern unique to F. oxysporum f.sp. apii race 2 was observed. Vegetative compatibility grouping could be accomplished more rapidly than greenhouse pathogenicity tests and more accurately identified race 2 isolates in a population of isolates of F. oxysporum from muck soils than did greenhouse pathogenicity tests or electrophoretic protein banding patterns. Key words: celery, fusarium yellows, nitrate-nonutilizing mutants, polyacrylamide gel electrophoresis.

Genetic variation within Saurodactylus and its phylogenetic relationships within the Gekkonoidea estimated from mitochondrial and nuclear DNA sequences

2008 ◽  
Vol 29 (1) ◽  
pp. 25-34 ◽  
Author(s):  
David James Harris ◽  
Catarina Rato
Keyword(s):  
Genetic Variation ◽  
Dna Sequences ◽  
Phylogenetic Relationships ◽  
Nuclear Dna ◽  
Taxonomic Position ◽  
Gene Region ◽  
12S Rrna ◽  
Nuclear Marker ◽  
Nuclear Markers ◽  
Mtdna Variability

Abstract Phylogenetic relationships of the three morphological forms within the gecko genus Saurodactylus were estimated using mtDNA (12S rRNA and ND4) sequences. High between morphological forms variation (up to 25% with ND4), confirms that all three deserve specific status. Saurodactylus mauritanicus and Saurodactylus brosseti are strongly supported as sister taxa. Our results again highlight the extremely high mtDNA variability almost universally reported from within gecko species. The position of Saurodactylus within the Gekkonoidea was also investigated. Although considered as a member of the sphaerodactyl geckos, its taxonomic position is still highly uncertain. Evaluation of C-mos nuclear DNA sequences supports many of the recent taxonomic rearrangements within the Gekkonoidea. Using this marker, Saurodactylus is paraphyletic, with S. mauritanicus and S. brosseti sister taxa to Teratoscincus przewalskii rather than Saurodactylus fasciatus. This is supported by a further nuclear marker, RAG1, although for this gene region sampling is more limited. Based on this paraphyly, supported by two independent nuclear markers, we suggest it likely that Saurodactylus will need to be partitioned into two genera, pending further investigations.

scholarly journals Population genetic variation analysis of bitter gourd wilt caused by Fusarium oxysporum f. sp. momordicae in China using inter simple sequence repeats (ISSR) molecular markers

2021 ◽  
Author(s):  
Rui Zang ◽  
Ying Zhao ◽  
Kangdi Guo ◽  
Kunqi Hong ◽  
Huijun Xi ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Differentiation ◽  
Fusarium Oxysporum ◽  
Diversity Index ◽  
Gene Diversity ◽  
Pcr Amplification ◽  
Bitter Gourd ◽  
Diseased Plant ◽  
Variation Analysis ◽  
Group I

AbstractBitter gourd wilt caused by Fusarium oxysporum f. sp. momordicae (FOM) is a devastating crop disease in China. A total of 173 isolates characteristic of typical Fusarium oxysporum with abundant microconidia and macroconidia on white or ruby colonies were obtained from diseased plant tissues. BLASTn analysis of the rDNA-ITS of the isolates showed 99% identity with F. oxysporum species. Among the tested isolates, three were infectious toward tower gourd and five were pathogenic to bottle gourd. However, all of the isolates were pathogenic to bitter gourd. For genetic differences analysis, 40 ISSR primers were screened and 11 primers were used for ISSR-PCR amplification. In total, 127 loci were detected, of which 76 were polymorphic at a rate of 59.84%. POPGENE analysis showed that Nei’s gene diversity index (H) and Shannon’s information index (I) were 0.09 and 0.15, respectively, which indicated that the genetic diversity of the 173 isolates was low. The coefficient of gene differentiation (Gst = 0.33 > 0.15) indicated that genetic differentiation was mainly among populations. The strength of gene flow (Nm = 1.01 > 1.0) was weak, indicating that the population differentiation caused by gene drift was blocked to some degree. The dendrogram based on ISSR markers showed that the nine geographical populations were clustered into two groups at the threshold of genetic similarity coefficient of 0.96. The Shandong and Henan populations were clustered into Group I, while the Guangdong, Hainan, Guangxi, Fujian, Jiangxi, and Hubei populations constituted Group II. Results of the genetic variation analysis showed that the Hunan and Guangxi populations had the highest degree of genetic differentiation, while the Hubei population had the lowest genetic differentiation. Our findings enrich the knowledge of the genetic variation characteristics of FOM populations with the goal of developing effective disease-management programs and resistance breeding programs.

scholarly journals Marker Development for Differentiation of Fusarium oxysporum f. sp. Niveum Race 3 from Races 1 and 2

2021 ◽  
Vol 22 (2) ◽  
pp. 822
Author(s):  
Owen Hudson ◽  
Sumyya Waliullah ◽  
James C. Fulton ◽  
Pingsheng Ji ◽  
Nicholas S. Dufault ◽  
...  
Keyword(s):  
South Carolina ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Conventional Polymerase Chain Reaction ◽  
Detection Methods ◽  
Limiting Factors ◽  
Pcr Marker ◽  
Primer Sets ◽  
Race Differentiation ◽  
Race 2

Fusarium wilt of watermelon, caused by Fusarium oxysporum f. sp. niveum (FON), is pathogenic only to watermelon and has become one of the main limiting factors in watermelon production internationally. Detection methods for this pathogen are limited, with few published molecular assays available to differentiate FON from other formae speciales of F. oxysporum. FON has four known races that vary in virulence but are difficult and costly to differentiate using traditional inoculation methods and only race 2 can be differentiated molecularly. In this study, genomic and chromosomal comparisons facilitated the development of a conventional polymerase chain reaction (PCR) assay that could differentiate race 3 from races 1 and 2, and by using two other published PCR markers in unison with the new marker, the three races could be differentiated. The new PCR marker, FNR3-F/FNR3-R, amplified a 511 bp region on the “pathogenicity chromosome” of the FON genome that is absent in race 3. FNR3-F/FNR3-R detected genomic DNA down to 2.0 pg/µL. This marker, along with two previously published FON markers, was successfully applied to test over 160 pathogenic FON isolates from Florida, Georgia, and South Carolina. Together, these three FON primer sets worked well for differentiating races 1, 2, and 3 of FON. For each marker, a greater proportion (60 to 90%) of molecular results agreed with the traditional bioassay method of race differentiation compared to those that did not. The new PCR marker should be useful to differentiate FON races and improve Fusarium wilt research.

scholarly journals Genetic variation in native and farmed populations of Tambaqui (Colossoma macropomum) in the Brazilian Amazon: regional discrepancies in farming systems

2013 ◽  
Vol 85 (4) ◽  
pp. 1439-1447 ◽  
Author(s):  
Jonas Aguiar ◽  
Horacio Schneider ◽  
Fatima Gomes ◽  
Jeferson Carneiro ◽  
Simoni Santos ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Dna Sequences ◽  
Amazon Basin ◽  
Farming Systems ◽  
Wild Populations ◽  
The West ◽  
Colossoma Macropomum ◽  
Breeding Stock ◽  
History Of

The tambaqui, Colossoma macropomum, is the most popular fish species used for aquaculture in Brazil but there is no study comparing genetic variation among native and farmed populations of this species. In the present study, we analyzed DNA sequences of the mitochondrial DNA to evaluate the genetic diversity among two wild populations, a fry-producing breeding stock, and a sample of fish farm stocks, all from the region of Santarém, in the west of the Brazilian state of Pará. Similar levels of genetic diversity were found in all the samples and surprisingly the breeding stock showed expressive representation of the genetic diversity registered on wild populations. These results contrast considerably with those of the previous study of farmed stocks in the states of Amapá, Pará, Piauí, and Rondônia, which recorded only two haplotypes, indicating a long history of endogamy in the breeding stocks used to produce fry. The results of the two studies show two distinct scenarios of tambaqui farming in the Amazon basin, which must be better evaluated in order to guarantee the successful expansion of this activity in the region, and the rest of Brazil, given that the tambaqui and its hybrids are now farmed throughout the country.

scholarly journals Multiple Evolutionary Trajectories Have Led to the Emergence of Races in Fusarium oxysporum f. sp. lycopersici

2016 ◽  
Vol 83 (4) ◽  
Author(s):  
V. Chellappan Biju ◽  
Like Fokkens ◽  
Petra M. Houterman ◽  
Martijn Rep ◽  
Ben J. C. Cornelissen
Keyword(s):  
Transposable Elements ◽  
Fusarium Oxysporum ◽  
Resistance Genes ◽  
Pcr Analysis ◽  
Genomic Fragment ◽  
Avirulence Genes ◽  
Content Type ◽  
Race 1 ◽  
Tomato Cultivars ◽  
Race 2

ABSTRACT Race 1 isolates of Fusarium oxysporum f. sp. lycopersici (FOL) are characterized by the presence of AVR1 in their genomes. The product of this gene, Avr1, triggers resistance in tomato cultivars carrying resistance gene I. In FOL race 2 and race 3 isolates, AVR1 is absent, and hence they are virulent on tomato cultivars carrying I. In this study, we analyzed an approximately 100-kb genomic fragment containing the AVR1 locus of FOL race 1 isolate 004 (FOL004) and compared it to the sequenced genome of FOL race 2 isolate 4287 (FOL4287). A genomic fragment of 31 kb containing AVR1 was found to be missing in FOL4287. Further analysis suggests that race 2 evolved from race 1 by deletion of this 31-kb fragment due to a recombination event between two transposable elements bordering the fragment. A worldwide collection of 71 FOL isolates representing races 1, 2, and 3, all known vegetative compatibility groups (VCGs), and five continents was subjected to PCR analysis of the AVR1 locus, including the two bordering transposable elements. Based on phylogenetic analysis using the EF1-α gene, five evolutionary lineages for FOL that correlate well with VCGs were identified. More importantly, we show that FOL races evolved in a stepwise manner within each VCG by the loss of function of avirulence genes in a number of alternative ways. IMPORTANCE Plant-pathogenic microorganisms frequently mutate to overcome disease resistance genes that have been introduced in crops. For the fungus Fusarium oxysporum f. sp. lycopersici, the causal agent of Fusarium wilt in tomato, we have identified the nature of the mutations that have led to the overcoming of the I and I-2 resistance genes in all five known clonal lineages, which include a newly discovered lineage. Five different deletion events, at least several of which are caused by recombination between transposable elements, have led to loss of AVR1 and overcoming of I. Two new events affecting AVR2 that led to overcoming of I-2 have been identified. We propose a reconstruction of the evolution of races in FOL, in which the same mutations in AVR2 and AVR3 have occurred in different lineages and the FOL pathogenicity chromosome has been transferred to new lineages several times.

Construction of a linkage map and identification of DNA markers linked to Fom-1, a gene conferring resistance to Fusarium oxysporum f.sp. melonis race 2 in melon

Euphytica ◽  
2009 ◽  
Vol 168 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Takahiro Tezuka ◽  
Keisuke Waki ◽  
Kazutoshi Yashiro ◽  
Maki Kuzuya ◽  
Tomoko Ishikawa ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Linkage Map ◽  
Dna Markers ◽  
Race 2

scholarly journals The Root Rot-Fusarium Wilt Complex of Peas

1963 ◽  
Vol 16 (1) ◽  
pp. 55 ◽  
Author(s):  
A Kerr
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Root Rot ◽  
Fungal Pathogens ◽  
South Australia ◽  
Pythium Ultimum ◽  
Wilt Symptom ◽  
Intensive Cropping ◽  
Race 2

At least four fungal pathogens are involved in the root rot-Fusarium wilt complex of peas which is a serious problem following intensive cropping of peas in South Australia. The pathogens are Fusarium oxysporum f. pisi race 2 Snyder & Hansen, F. solani f. pisi Snyder & Hansen, Pythium ultimum Trow, and Ascochyta pinodella L. K. Jones. In susceptible pea cultivars there is a marked interaction between F. oxysporum and P. ultimum. P. ultimum alone causes initial stunting from which plants gradually recover; F. OX1Jsporum alone probably CRuses little damage; both fungi together CRuse initial stunting followed by severe wilt symptom about 6 weeks after sowing and death 2 weeks later. The importance ofF. solani and A. pinodella has not been fully determined, but they probably cause only minor damage.

Quantifying genetic variation at the molecular level

2019 ◽  
pp. 34-66
Author(s):  
Asher D. Cutter
Keyword(s):  
Genetic Variation ◽  
Dna Sequences ◽  
Migration Rate ◽  
Population Genetic ◽  
Quantitative Methods ◽  
Molecular Level ◽  
Effective Population ◽  
Fundamental Properties ◽  
Site Frequency Spectrum ◽  
Population Genetic Variation

Chapter 3, “Quantifying genetic variation at the molecular level,” introduces quantitative methods for measuring variation directly in DNA sequences to help decipher fundamental properties of populations and what they can tell us about evolution. It provides an overview of the evolutionary factors that contribute to genetic variation, like mutational input, effective population size, genetic drift, migration rate, and models of migration. This chapter surveys the principal ways to measure and summarize polymorphisms within a single population and across multiple populations of a species, including heterozygosity, nucleotide polymorphism estimators of θ‎, the site frequency spectrum, and F ST, and by providing illustrative natural examples. Populations are where evolution starts, after mutations arise as the spark of population genetic variation, and Chapter 3 describes how to quantify the variation to connect observations to predictions about how much polymorphism there ought to be under different circumstances.

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