Reproduction of Meloidogyne arenaria race 2 on Flue-cured tobacco possessing resistance genes Rk1 and/or Rk2

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.

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IDENTIFICATION OF RESISTANCE GENES IN BARLEY BY REACTIONS TO USTILAGO NUDA

Canadian Journal of Plant Science ◽

10.4141/cjps69-073 ◽

1969 ◽

Vol 49 (4) ◽

pp. 447-451 ◽

Cited By ~ 5

Author(s):

J. G. Moseman ◽

D. R. Metcalfe

Keyword(s):

Hordeum Vulgare ◽

Resistance Genes ◽

Smut Fungus ◽

Loose Smut ◽

Hordeum Vulgare L ◽

Race 1 ◽

Ustilago Nuda ◽

Race 2 ◽

Or Genes ◽

Similar Gene

The reactions of 18 cultivars and selections of barley, Hordeum vulgare L., to inoculations with three cultures of the loose smut fungus, Ustilago nuda (Jens.) Rostr., were determined. The following conclusions were derived by analyzing the reactions of cultivars Jet (CI 967) and Milton (CI 4966) and derivatives from them to inoculations with cultures 244 of race 2, 49-70 of race 2, and 10 of race 1. Jet was shown to have two genes, Un3 and Un6, and Milton, one gene, Un8. Derivatives from Jet with only gene Un6 were distinguished from those with genes Un3 and Un6. Five host selections known to have a gene or genes at the same locus as Jet were shown to have gene Un6 or a similar gene at that locus.

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Greenhouse and field resistance in cucumber to root-knot nematodes

Nematology ◽

10.1163/156854199508270 ◽

1999 ◽

Vol 1 (3) ◽

pp. 279-284 ◽

Cited By ~ 5

Author(s):

S. Alan Walters ◽

Todd C. Wehner ◽

Kenneth R. Barker

Keyword(s):

Cucumis Sativus ◽

Multiple Root ◽

Nematode Species ◽

Nematode Resistance ◽

Field Resistance ◽

Field Conditions ◽

Meloidogyne Arenaria ◽

Root Knot Nematode ◽

Root Knot Nematodes ◽

Race 2

Abstract Ten cultigens were evaluated for resistance to Meloidogyne arenaria races 1 and 2, and M. javanica under greenhouse and field conditions. Resistance to M. arenaria races 1 and 2, and M. javanica was verified in Cucumis sativus var. hardwickii line LJ 90430 and to M. arenaria race 2 in C. sativus var. sativus Southern Pickler and Mincu in a greenhouse test. Another cultigen of C. sativus var. hardwickii (PI 215589) was found to be resistant to M. arenaria race 2 but not to other root-knot nematode species tested. LJ 90430 is the cultigen of choice to develop root-knot nematode resistant cucumbers, since it has multiple root-knot nematode resistance and is cross-compatible with cucumber. Greenhouse and field data were positively correlated (r = 0.74) over both years. Experiment repeatabilities were calculated from the cultigens infected with root-knot nematodes under both greenhouse and field conditions. Four environments (greenhouse and field over 2 years) were used in the analysis. Repeatabilities were high in all instances (ranging from 0.83-0.99) and indicated that the environment (field or greenhouse) was not an important factor in assessing root-knot nematode resistance for the cultigens evaluated. Resistenz von Gurkengegen Wurzelgallennematoden im Gewachshaus undim Freiland - Unter Gewachshausund Freilandbedingungen wurden zehn Cultigene auf ihre Resistenz gegen Meloidogyne arenaria Rassen 1 und 2 und gegen M. javanica gepruft. Bei Cucumis sativus var. hardwickii Linie LJ 90430 wurde im Gewachshausversuch Resistenz gegen M. arenaria Rassen 1 und 2 sowie gegen M. javanica nachgewiesen, und in C. sativus var. sativus "Southern Pickler" und "Mincu" Resistenz gegen M. arenaria Rasse 2. Cultigen C. sativus var. hardwickii (PI 215589) war resistent gegen M. arenaria Rasse 2 aber nicht gegen die anderen gepruften Arten von Wurzelgallennematoden. LJ 90430 ist das Cultigen der Wahl bei der Entwicklung von Gurken, die gegen Wurzelgallennematoden resistent sind, da es multiple Resistenzen gegen Wurzelgallennematoden besitzt und kreuzungsvertraglich mit Gurke ist. Die Ergebnisse der Gewachshaus- und Feldversuche waren uber beide Versuchsjahre hin positiv korreliert (r = 0,74). Ausgehend von den Cultigenen, die im Gewachshaus und im Freiland mit Wurzelgallennematoden infiziert waren, wurden die Wiederholbarkeiten der Versuche berechnet. Dabei wurden vier verschiedene Umweltbedingungen (Gewachshaus und Freiland uber zwei Jahre) verwendet. Die Wiederholbarkeiten waren in allen Fallen hoch (0,83-0,99) und zeigten an, dass die Umwelt (Freiland oder Gewachshaus) kein wichtiger Faktor bei der Bestimmung der Resistenz gegen Wurzelgallennematoden bei den gepruften Cultigenen war.

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Characterization of Resistance Conferred by the N gene to Meloidogyne arenaria Races 1 and 2, M. hapla, and M. javanica in Two Sets of Isogenic Lines of Capsicum annuum L.

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.125.1.71 ◽

2000 ◽

Vol 125 (1) ◽

pp. 71-75 ◽

Cited By ~ 26

Author(s):

Judy A. Thies ◽

Richard L. Fery

Keyword(s):

Capsicum Annuum ◽

Nematode Resistance ◽

N Gene ◽

Recurrent Parent ◽

Resistance Locus ◽

Meloidogyne Arenaria ◽

Meloidogyne Hapla ◽

Root Knot Nematode ◽

Race 1 ◽

Race 2

Two isogenic sets of bell pepper (Capsicum annuum L.) lines (differing at the N root-knot nematode resistance locus) were characterized for resistance to Meloidogyne arenaria (Neal) Chitwood races 1 and 2, M. hapla Chitwood, and M. javanica (Treub) Chitwood in greenhouse and growth chamber tests. The isogenic sets of C. annuum were `Charleston Belle' (NN) and `Keystone Resistant Giant' (nn-recurrent parent), and `Carolina Wonder' (NN) and `Yolo Wonder B' (nn-recurrent parent). Meloidogyne arenaria race 1 is pathogenic to C. annuum. `Charleston Belle' and `Carolina Wonder' exhibited high resistance to M. arenaria race 1. Their respective recurrent backcross parents, `Keystone Resistant Giant' and `Yolo Wonder B', were susceptible to M. arenaria. Meloidogyne arenaria race 2 and M. javanica are not highly pathogenic to pepper. However, `Charleston Belle' and `Carolina Wonder' both exhibited higher (P≤0.05) resistance to M. arenaria race 2 and M. javanica than `Keystone Resistant Giant' and `Yolo Wonder B'. Meloidogyne hapla is pathogenic to pepper. Both `Charleston Belle' and `Carolina Wonder' and their respective recurrent parents, `Keystone Resistant Giant' and `Yolo Wonder B', were susceptible to M. hapla. We concluded that the N gene confers resistance to M. arenaria races 1 and 2, and M. javanica in C. annuum, but the N gene does not condition resistance to M. hapla.

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Reproduction of Meloidogyne arenaria race 2 on flue-cured tobacco with putative resistance derived from Nicotiana repanda

Journal of Nematology ◽

10.21307/jofnem-2021-064 ◽

2021 ◽

Vol 53 ◽

pp. 1-9

Author(s):

Noah Adamo ◽

Charles S. Johnson ◽

T. David Reed ◽

Jonathan D. Eisenback

Keyword(s):

Meloidogyne Arenaria ◽

Race 2

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Cosegregation of Avr4 and Avr6 in Phytophthora sojae

Canadian Journal of Botany ◽

10.1139/b96-100 ◽

1996 ◽

Vol 74 (5) ◽

pp. 800-802 ◽

Cited By ~ 29

Author(s):

Mark Gijzen ◽

Helga Förster ◽

Michael D. Coffey ◽

Brett Tyler

Keyword(s):

Glycine Max ◽

Genetic Mapping ◽

Resistance Genes ◽

Gene Interaction ◽

Phytophthora Sojae ◽

Phytophthora Megasperma ◽

Incomplete Dominance ◽

Soybean Plants ◽

Race 2 ◽

Gene For Gene

The F2 progeny resulting from a cross of Phytophthora sojae race 2 (avirulent on Rps4 and Rps6) and race 7 (virulent on Rps4 and Rps6) were tested for their ability to cause disease on soybean plants carrying the Rps4 or the Rps6 resistance genes. Of 55 F2 progeny analyzed, 41 individuals were avirulent on both of these genes and 14 were virulent on Rps4 and Rps6, indicating that avirulence on Rps4 and Rps6 is dominant and linked. These results support the suggestion that the soybean–Phytophthora relationship is a gene for gene interaction and that the presumptive Avr4 and Avr6 genes are either tightly linked or identical. Keywords: avirulence, genetic mapping, Glycine max, incomplete dominance, Phytophthora megasperma f.sp. glycinea.

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RFLP-based Analysis of Recombination Among Resistance Genes to Fusarium Wilt

HortScience ◽

10.21273/hortsci.39.4.868e ◽

2004 ◽

Vol 39 (4) ◽

pp. 868E-869

Author(s):

John W. Scott* ◽

Hesham A. Agrama ◽

John P. Jones

Keyword(s):

Fusarium Wilt ◽

Resistance Genes ◽

Dominant Gene ◽

Chromosome 7 ◽

Rflp Markers ◽

Single Dominant Gene ◽

Chromosome 11 ◽

Intermediate Resistance ◽

Race 1 ◽

Race 2

Tomato (Lycopersicon esculentum) line E427 has resistance genes to three races of Fusarium oxysporum f.sp. lycopersici derived from L. pennellii (L.pen) accession LA 716 and L. pimpinellifolium (L.pimp) accession PI 126915. E427 was crossed to susc. Bonny Best and F2 and backcross seed were obtained. Progeny were inoculated separately with Fusarium wilt races 1, 2, or 3. Lines with suspected recombination of resistance were selfed and re-inoculated until disease reactions were homozygous. Four lines were obtained with resistance to both races 2 and 3, but susceptible to race 1. These lines had the L.pen alleles at RFLP markers linked to I-3 on chromosome 7 and lacked L.pimp alleles linked to I and I-2 on chromosome 11. Complementation (F2) data indicated race 2 resistance on chromosome 7 was controlled by a single dominant gene. Three lines were resistant to race 2, but susceptible to races 1 and 3. These lines had L.pimp alleles at TG105 indicating the presence of I-2, and no L.pen alleles at markers linked to I-3. Three lines were resistant to race 1, but susceptible to races 2 and 3. All three had L.pimp alleles at TG523 confirming linkage to I on chromosome 11 and no L.pen alleles at markers tightly linked to I-3. However, one of the lines had L.pen alleles at CT113 on chromosome 7. This and F2 complementation data suggests the possible location of a race 1 resistant locus, I1. Two lines that were Fusarium wilt race 3 resistant and susceptible to race 1 had intermediate resistance to race 2. These two lines did not have the L. pennellii alleles at TG183, TG174, and CT43 near the I-3 locus indicating crossovers in this region reduced race 2 resistance.

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Soil temperature and egg mass formation by Meloidogyne arenaria on oriental melon (Cucumis melo L.)

Nematology ◽

10.1163/156854103322746896 ◽

2003 ◽

Vol 5 (5) ◽

pp. 721-725 ◽

Cited By ~ 6

Author(s):

So Deuk Park ◽

Dong Geun Kim ◽

Il Kweon Yeon

Keyword(s):

Soil Temperature ◽

Threshold Temperature ◽

Egg Mass ◽

Data Sets ◽

Meloidogyne Arenaria ◽

Degree Days ◽

Oriental Melon ◽

Race 2 ◽

Cucumis Melo L ◽

Mass Formation

AbstractEgg masses of Meloidogyne arenaria race 2 were observed on the second planting of oriental melon by the time of its first harvest under glasshouse conditions in Korea. Time and degree-days above 5°C (DD5) for egg mass formation after April were about 24.5 days and 500 DD5. Higher mean soil temperature shortened the days required for egg mass formation. A threshold temperature for degree-days accumulation of 12.2°C was selected on the basis of lowest coefficient of variation among data sets of time to egg mass formation. We propose the use of DD12.2 for predicting the time to egg mass formation of M. arenaria under these glasshouse conditions.

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First Report of the Root-Knot Nematode Meloidogyne arenaria Race 2 from Several Vegetable Crops in Jordan

Plant Disease ◽

10.1094/pd-89-0206b ◽

2005 ◽

Vol 89 (2) ◽

pp. 206-206 ◽

Cited By ~ 3

Author(s):

M. Karajeh ◽

W. Abu-Gharbieh ◽

S. Masoud

Keyword(s):

North Carolina ◽

Meloidogyne Arenaria ◽

Vegetable Crops ◽

Root Knot Nematode ◽

Lateral Field ◽

Differential Host ◽

First Report ◽

Race 1 ◽

Meloidogyne Spp ◽

Race 2

Meloidogyne arenaria (Neal) Chitwood (race 2) is reported for the first time in Jordan. The nematode populations were recovered from several vegetable crops, including tomato (Lycopersicon esulentum Mill), squash (Cucurbita pepo L.), cucumber (Cucumis sativus L.), and bean (Phaseolus vulgaris L.), at Dier Alla in the northern area of the Jordan Valley. Symptoms included root galling, leaf chlorosis, and stunting. Galled plant root samples were collected during a survey conducted from May 2002 to August 2003 covering most of the irrigated agricultural areas of Jordan. Eighty-three Meloidogyne spp. populations were collected from various vegetable crops and fruit trees. Identification to species and race levels of the nematode populations was based on combination of currently available methods including nematode morphology, host preference based on the North Carolina (NC) differential host test (1), and cytogenetics and DNA-fingerprinting. Seventy of the eighty-three collected populations were identified as M. javanica, five as M. incognita (race 1), three as M. incognita (race 2), and five as M. arenaria (race 2). The perineal patterns of M. arenaria were characterized by a low, round to indented dorsal arch near the lateral field with irregular forks in the lateral field, fine smooth striae, and a distinct whorl. Race 2 was identified with the NC differential host test. Cytogenetic studies indicated that M. arenaria populations were triploid with an average of 52.2 chromosomes, while the populations of M. incognita (race 1), M. incognita (race 2), and M. javanica were hypotriploid with an average of 45.2, 46.1, and 46.7 chromosomes, respectively. Two polymerase chain reaction (PCR)-based assays were used to confirm species identification and to study genetic variability of the Meloidogyne spp. populations including sequence characterized amplified regions (SCAR) and random amplified polymorphic DNA (RAPD). In the SCAR-PCR-based assay (2), typical DNA products of 420, 670, or 1,200 bp in size were amplified by using extracted DNA of M. arenaria (race 2), M. javanica, or M. incognita (race 1 or 2), respectively, as template DNA. The RAPD-PCR primer, OPA-01, produced DNA patterns with bands that clearly distinguished M. arenaria from the other two Meloidogyne spp. To our knowledge, this is the first report of the root-knot nematode, M. arenaria race 2, in Jordan. References: (1) A. Taylor and J. Sasser, North Carolina State University Graphics, Raleigh, NC, 1978. (2) C. Zijlstra et al. Nematology 2:847, 2000.

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UPDATE ON POWDERY MILDEW RESISTANCE SCREENING IN WATERMELON

HortScience ◽

10.21273/hortsci.40.3.872c ◽

2005 ◽

Vol 40 (3) ◽

pp. 872c-872

Author(s):

Angela R. Davis ◽

Todd C. Wehner ◽

Amnon Levi ◽

Stephen R. King

Keyword(s):

United States ◽

South Carolina ◽

Powdery Mildew ◽

Resistance Genes ◽

Citrullus Lanatus ◽

Germplasm Collection ◽

The United States ◽

The Past ◽

Race 1 ◽

Race 2

Powdery mildew has been reported on Citrullus lanatus in Africa and Europe for the past 9 years, and in the United States for the past 6 years. During this time, it has occurred in the main watermelon production areas in the U.S. and has been documented in nine states (South Carolina, Georgia, Florida, Oklahoma, Texas, Maryland, New York, Arizona, and California). This is of great concern to the watermelon industry since powdery mildew is difficult to control and can have a severe impact on yield and fruit quality due to loss of photosynthetic area and sunscald. Finding resistant C. lanatus germplasm is needed for the development of commercial varieties containing this resistance. This report summarized the status of an ongoing project to screen the entire USDA–ARS C. lanatus germplasm collection. Currently, the collection is being screened for race 1 and race 2 Podosphaera xanthii (syn. Sphaerotheca fuliginea auct. p.p.), the causal agent of powdery mildew in C. lanatus in the United States. Resistance genes appear to exist for both races and the genes conferring resistance to race 1 appear to be different than race 2 resistance genes. Allelism tests are currently in process to determine the number of resistance genes present.

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