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A high-resolution map of the Grp1 locus on chromosome V of potato harbouring broad-spectrum resistance to the cyst nematode species Globodera pallida and Globodera rostochiensis.

Finkers-Tomczak A, Danan S, van Dijk T, Beyene A, Bouwman L, Overmars H, van Eck H, Goverse A, Bakker J, Bakker E - Theor. Appl. Genet. (2009)

Bottom Line: A high-resolution map has been developed using the diploid mapping population RHAM026, comprising 1,536 genotypes.Interval mapping of the resistances to G. pallida Pa2 and G. rostochiensis Ro5 resulted in two nearly identical LOD graphs with the highest LOD score just north of marker TG432.It is suggested that the quantitative resistance to both nematode species at the Grp1 locus is mediated by one or more tightly linked R genes that might belong to the NBS-LRR class.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Nematology, Plant Science Group, Wageningen University, Wageningen, The Netherlands.

ABSTRACT
The Grp1 locus confers broad-spectrum resistance to the potato cyst nematode species Globodera pallida and Globodera rostochiensis and is located in the GP21-GP179 interval on the short arm of chromosome V of potato. A high-resolution map has been developed using the diploid mapping population RHAM026, comprising 1,536 genotypes. The flanking markers GP21 and GP179 have been used to screen the 1,536 genotypes for recombination events. Interval mapping of the resistances to G. pallida Pa2 and G. rostochiensis Ro5 resulted in two nearly identical LOD graphs with the highest LOD score just north of marker TG432. Detailed analysis of the 44 recombinant genotypes showed that G. pallida and G. rostochiensis resistance could not be separated and map to the same location between marker SPUD838 and TG432. It is suggested that the quantitative resistance to both nematode species at the Grp1 locus is mediated by one or more tightly linked R genes that might belong to the NBS-LRR class.

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Related in: MedlinePlus

Distribution graphs for the number of G. rostochiensis cysts (a) and G. pallida cysts (b). The Y axes represent the number of cysts per plant. The X axes represent the potato genotypes. In the potato genotypes to the left of the dashed vertical line, marker TG432 is present and in the potato genotypes to the right of this line, marker TG432 is absent. Potato genotypes in the grey areas are classified as intermediate, while those above the grey areas are classified as susceptible and those below as resistant. Potato genotypes that are discussed in the text are indicated with a code
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Fig3: Distribution graphs for the number of G. rostochiensis cysts (a) and G. pallida cysts (b). The Y axes represent the number of cysts per plant. The X axes represent the potato genotypes. In the potato genotypes to the left of the dashed vertical line, marker TG432 is present and in the potato genotypes to the right of this line, marker TG432 is absent. Potato genotypes in the grey areas are classified as intermediate, while those above the grey areas are classified as susceptible and those below as resistant. Potato genotypes that are discussed in the text are indicated with a code

Mentions: Grp1 resistance is located in an interval that is known to harbour single dominant R genes in other potato genotypes (Kuang et al. 2005; Ballvora et al. 2007). In addition, because PCN are obligatory outbreeding nematode species, the nematode populations used to test for resistance are most likely a mixture of virulent and avirulent genotypes (Janssen et al. 1990). Therefore, it is possible that the quantitative effect of the Grp1 resistance is caused by the genetic diversity of the nematodes and that resistance is monogenic. To test this, the plant genotypes were first sorted on the presence or absence of the closest marker, which is TG432 for both G. rostochiensis (LOD 7.3) and G. pallida (LOD 7.9) resistance, and then according to ascending cyst numbers (Fig. 3). For the majority of the genotypes, the presence of marker TG432 was indicative of the degree of resistance (Fig. 3). A small number of genotypes with an intermediate level of resistance lacked a correlation with marker TG432, indicating that also other regions in the potato genome affect the degree of resistance.Fig. 3


A high-resolution map of the Grp1 locus on chromosome V of potato harbouring broad-spectrum resistance to the cyst nematode species Globodera pallida and Globodera rostochiensis.

Finkers-Tomczak A, Danan S, van Dijk T, Beyene A, Bouwman L, Overmars H, van Eck H, Goverse A, Bakker J, Bakker E - Theor. Appl. Genet. (2009)

Distribution graphs for the number of G. rostochiensis cysts (a) and G. pallida cysts (b). The Y axes represent the number of cysts per plant. The X axes represent the potato genotypes. In the potato genotypes to the left of the dashed vertical line, marker TG432 is present and in the potato genotypes to the right of this line, marker TG432 is absent. Potato genotypes in the grey areas are classified as intermediate, while those above the grey areas are classified as susceptible and those below as resistant. Potato genotypes that are discussed in the text are indicated with a code
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2690855&req=5

Fig3: Distribution graphs for the number of G. rostochiensis cysts (a) and G. pallida cysts (b). The Y axes represent the number of cysts per plant. The X axes represent the potato genotypes. In the potato genotypes to the left of the dashed vertical line, marker TG432 is present and in the potato genotypes to the right of this line, marker TG432 is absent. Potato genotypes in the grey areas are classified as intermediate, while those above the grey areas are classified as susceptible and those below as resistant. Potato genotypes that are discussed in the text are indicated with a code
Mentions: Grp1 resistance is located in an interval that is known to harbour single dominant R genes in other potato genotypes (Kuang et al. 2005; Ballvora et al. 2007). In addition, because PCN are obligatory outbreeding nematode species, the nematode populations used to test for resistance are most likely a mixture of virulent and avirulent genotypes (Janssen et al. 1990). Therefore, it is possible that the quantitative effect of the Grp1 resistance is caused by the genetic diversity of the nematodes and that resistance is monogenic. To test this, the plant genotypes were first sorted on the presence or absence of the closest marker, which is TG432 for both G. rostochiensis (LOD 7.3) and G. pallida (LOD 7.9) resistance, and then according to ascending cyst numbers (Fig. 3). For the majority of the genotypes, the presence of marker TG432 was indicative of the degree of resistance (Fig. 3). A small number of genotypes with an intermediate level of resistance lacked a correlation with marker TG432, indicating that also other regions in the potato genome affect the degree of resistance.Fig. 3

Bottom Line: A high-resolution map has been developed using the diploid mapping population RHAM026, comprising 1,536 genotypes.Interval mapping of the resistances to G. pallida Pa2 and G. rostochiensis Ro5 resulted in two nearly identical LOD graphs with the highest LOD score just north of marker TG432.It is suggested that the quantitative resistance to both nematode species at the Grp1 locus is mediated by one or more tightly linked R genes that might belong to the NBS-LRR class.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Nematology, Plant Science Group, Wageningen University, Wageningen, The Netherlands.

ABSTRACT
The Grp1 locus confers broad-spectrum resistance to the potato cyst nematode species Globodera pallida and Globodera rostochiensis and is located in the GP21-GP179 interval on the short arm of chromosome V of potato. A high-resolution map has been developed using the diploid mapping population RHAM026, comprising 1,536 genotypes. The flanking markers GP21 and GP179 have been used to screen the 1,536 genotypes for recombination events. Interval mapping of the resistances to G. pallida Pa2 and G. rostochiensis Ro5 resulted in two nearly identical LOD graphs with the highest LOD score just north of marker TG432. Detailed analysis of the 44 recombinant genotypes showed that G. pallida and G. rostochiensis resistance could not be separated and map to the same location between marker SPUD838 and TG432. It is suggested that the quantitative resistance to both nematode species at the Grp1 locus is mediated by one or more tightly linked R genes that might belong to the NBS-LRR class.

Show MeSH
Related in: MedlinePlus