Mapping strategy for resistance genes in tomato based on RFLPs between cultivars: Cf9 (resistance to Cladosporium fulvum) on chromosome 1

Beek, J.G. van der; Verkerk, Ruud; Zabel, P.; Lindhout, P.

doi:10.1007/bf00223988

Cited by 154 publications

(73 citation statements)

References 24 publications

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“…For the construction of chimeric Hcr9s, genomic DNA was isolated (20) from Lp plants and used as a template for PCR. Fragments of Hcr9s encoding LRRs 1-17 were amplified with primers CF1 and BR1 and cloned into the ClaI and BamHI restriction sites, thereby constructing chimeric Hcr9s (Fig.…”

Section: Methodsmentioning

confidence: 99%

Intragenic recombination generated two distinct Cf genes that mediate AVR9 recognition in the natural population of Lycopersicon pimpinellifolium

Hoorn

Kruijt

Roth

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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Resistance gene Cf-9 of cultivated tomato (Lycopersicon esculentum) confers recognition of the AVR9 elicitor protein of the fungal pathogen Cladosporium fulvum. The Cf-9 locus, containing Cf-9 and four homologs (Hcr9s), originates from Lycopersicon pimpinellifolium (Lp). We examined naturally occurring polymorphism in Hcr9s that confer AVR9 recognition in the Lp population. AVR9 recognition occurs frequently throughout this population. In addition to Cf-9, we discovered a second gene in Lp, designated 9DC, which also confers AVR9 recognition. Compared with Cf-9, 9DC is more polymorphic, occurs more frequently, and is more widely spread throughout the Lp population, suggesting that 9DC is older than Cf-9. The sequences of Cf-9 and 9DC suggest that Cf-9 evolved from 9DC by intragenic recombination between 9DC and another Hcr9. The fact that the 9DC and Cf-9 proteins differ in 61 aa residues, and both mediate recognition of AVR9, shows that in nature Hcr9 proteins with the same recognitional specificity can vary significantly. R ecognition of a diverse range of pathogens, followed by an adequate defense response, is crucial for the survival of plants. Resistance (R) genes, which mediate recognition of products of matching avirulence (Avr) genes, play a key role in the recognition of pathogens (1). Most R gene products contain a leucine-rich repeat (LRR) domain with putative solventexposed amino acid residues that decorate the surface of the protein, where specific interactions with other proteins are thought to occur (2). R proteins with different specificities differ predominantly at putative solvent-exposed positions, which are often thought to result from adaptive evolution (3).Plants need to generate R genes with new specificities because pathogens continuously try to circumvent recognition by the host plant. New R genes are thought to evolve by sequence exchange between homologous genes and by accumulation of random point mutations in codons that encode amino acids located at putative solvent-exposed positions (3, 4).The continuous generation of new recognitional specificities by the host, followed by subsequent adaptation of the pathogen to circumvent this recognition, can be seen as an ''arms race'' between plants and pathogens (5). Recent observations suggest that in nature, this arms race is a slow process and that the battle between plants and pathogens is more likely to be similar to ''trench warfare.'' In this model, frequencies of R genes in the plant population fluctuate in time, following the frequency of the matching Avr gene in the pathogen population (6). Consistent with this model, gene-for-gene pairs like AvrRpm1-RPM1 and AvrPto-Pto are ancient (6, 7), and plants carrying or lacking the RPM1 gene coexist in the plant population (6).The tomato R genes Cf-9 and Cf-4 mediate recognition of strains of the leaf mold fungus Cladosporium fulvum carrying the Avr9 or Avr4 gene, respectively (8). Recognition by resistant plants results in the activation of multiple defense responses that limit further fun...

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Section: Methodsmentioning

confidence: 99%

Intragenic recombination generated two distinct Cf genes that mediate AVR9 recognition in the natural population of Lycopersicon pimpinellifolium

Hoorn

Kruijt

Roth

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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“…Tomato DNA was extracted by a method described previously (Van Der Beek et al, 1992). Southern hybridizations and radioactive labelling of probes were done according to standard procedures (Church and Gilbert, 1984;Sambrook et al, 1989).…”

Section: Dna Isolation and Cloningmentioning

confidence: 99%

Identification and Ds‐tagged isolation of a new gene at the Cf‐4 locus of tomato involved in disease resistance to Cladosporium fulvum race 5

Takken¹,

Schipper²,

Nijkamp³

et al. 1998

The Plant Journal

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SummaryLeaf mould disease in tomato is caused by the biotrophic fungus Cladosporium fulvum. An Ac/Ds targeted transposon tagging strategy was used to isolate the gene conferring resistance to race 5 of C. fulvum, a strain expressing the avirulence gene Avr4. An infection assay of 2-weekold seedlings yielded five susceptible mutants, of which two had a Ds element integrated in the same gene at different positions. This gene, member of a gene family, showed high sequence homology to the C. fulvum resistance genes Cf-9 and Cf-2. The gene is predicted to encode an extracellular transmembrane protein containing a divided domain of 25 leucine-rich repeats. Three mutants exhibited a genomic deletion covering most of the Lycopersicon hirsutum introgressed segment, including the Cf-4 locus. Southern blot analysis revealed that this deletion includes the tagged gene and five homologous sequences. To test whether the tagged gene confers resistance to C. fulvum via Avr4 recognition, the Avr4 gene was expressed in planta. Surprisingly, expression of the Avr4 gene still triggered a specific necrotic response in the transposon-tagged plants, indicating that the tagged resistance gene is not, or is not the only gene, involved in Avr4 recognition. Mutants harbouring the genomic deletion did not show this Avr4-specific response. The deleted segment apparently contains, in addition to the tagged gene, one or more other genes, which play a role in the Avr4 responses. The tagged gene is present at the Cf-4 locus, but it does not necessarily recognize Avr4 and is therefore designated Cf-4A.

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“…Genomic DNA was isolated according to Van der Beek et al (1992) from four-week-old leaves of the breeding line Ontario 7518 (Cf18) showing Cf-Ecp2-mediated resistance (Lauge´et al 1998). DNA was partially digested with Sau3A I to an average size of 40 kb.…”

Section: Experimental Procedures Pcld04541 Binary Cosmid Library Consmentioning

confidence: 99%

“…Genomic DNA from 4-week-old leaves of the breeding line Ontario 7518 (Cf18) showing Cf-Ecp2-mediated resistance (Lauge´et al 1998) was isolated according to the protocol described of Van der Beek et al (1992). DNA was partially digested with Sau3A I to an average size of 40 kb and size-fractionated on a 10-40% sucrose gradient (Sambrook et al 1989).…”

Section: K-bluestar Library Construction and Screeningmentioning

confidence: 99%

“…A number of Cf resistance genes have been mapped at four different loci. Cf-2 and Cf-5 are closely linked and map on chromosome 6 (Dixon et al 1996(Dixon et al , 1998, Cf-4, Cf-4E and Cf-9 have been mapped on the short arm of chromosome 1 at the Milky Way (MW) locus (Van der Beek et al 1992;Balint-Kurti et al 1994;Takken et al 1998), Cf-Ecp5 at the Aurora (AU) locus, 4 cM(centiMorgan) proximal to the MW cluster (Haanstra et al 2000) and Cf-Ecp2 and Cf-Ecp3 at the Orion (OR) locus, 12 cM proximal to the MW locus (Haanstra et al 1999;Yuan et al 2002), see also Figure 5. Several Cf genes, notably Cf-9 , Cf-2 (Dixon et al 1996) Cf-4 (Thomas et al 1997, Cf-4E (Takken et al 1998), Cf-5 (Dixon et al 1998) and 9DC (Van der Hoorn et al 2001a; M. Kruijt et al 2004) have been cloned and sequenced.…”

Section: Introductionmentioning

confidence: 99%

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The tomato Orion locus comprises a unique class of Hcr9 genes

et al. 2005

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Resistance against the tomato fungal pathogen Cladosporium fulvum is often conferred by Hcr9 genes (Homologues of the C. fulvum resistance gene Cf-9) that are located in the Milky Way cluster on the short arm of chromosome 1. These Hcr9 genes mediate recognition of fungal avirulence gene products. In contrast, the resistance gene Cf-Ecp2 mediates recognition of the virulence factor Ecp2 and is located in the Orion (OR) cluster on the short arm of chromosome 1. Here, we report the map-and homology-based cloning of the OR Hcr9 cluster. A method was optimised to generate clone-specific fingerprint data that were subsequently used in the efficient calculation of genomic DNA contigs. Three Hcr9s were identified as candidate Cf-Ecp2 genes. By PCR-based cloning using specific OR sequences, orthologous Hcr9 genes were identified from different Lycopersicon species and haplotypes. The OR Hcr9s are very homologous. However, based on the relative low sequence homology to other Hcr9s, the OR Hcr9s are classified as a new subgroup.

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Mapping strategy for resistance genes in tomato based on RFLPs between cultivars: Cf9 (resistance to Cladosporium fulvum) on chromosome 1

Cited by 154 publications

References 24 publications

Intragenic recombination generated two distinct Cf genes that mediate AVR9 recognition in the natural population of Lycopersicon pimpinellifolium

Intragenic recombination generated two distinct Cf genes that mediate AVR9 recognition in the natural population of Lycopersicon pimpinellifolium

Identification and Ds‐tagged isolation of a new gene at the Cf‐4 locus of tomato involved in disease resistance to Cladosporium fulvum race 5

The tomato Orion locus comprises a unique class of Hcr9 genes

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