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Peroxidase profiling reveals genetic linkage between peroxidase gene clusters and basal host and non-host resistance to rusts and mildew in barley.

González AM, Marcel TC, Kohutova Z, Stam P, van der Linden CG, Niks RE - PLoS ONE (2010)

Bottom Line: We examined the association between the Prxs mapped and the QTLs for resistance of barley to homologous and heterologous rusts, and to the barley powdery mildew fungus.We conclude that Prx-Profiling was effective in finding the genetic location of Prx genes on the barley genome.The finding that QTLs for basal resistance to rusts and powdery mildew fungi tend to co-locate with Prx clusters provides a base for exploring the functional role of Prx-related genes in determining natural differences in levels of basal resistance.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Plant Breeding, Wageningen University and Research Center, Wageningen, The Netherlands.

ABSTRACT

Background: Higher plants possess a large multigene family encoding secreted class III peroxidase (Prx) proteins. Peroxidases appear to be associated with plant disease resistance based on observations of induction during disease challenge and the presence or absence of isozymes in resistant vs susceptible varieties. Despite these associations, there is no evidence that allelic variation of peroxidases directly determines levels of disease resistance.

Methodology/principal findings: The current study introduces a new strategy called Prx-Profiling. We showed that with this strategy a large number of peroxidase genes can be mapped on the barley genome. In order to obtain an estimate of the total number of Prx clusters we followed a re-sampling procedure, which indicated that the barley genome contains about 40 peroxidase gene clusters. We examined the association between the Prxs mapped and the QTLs for resistance of barley to homologous and heterologous rusts, and to the barley powdery mildew fungus. We report that 61% of the QTLs for partial resistance to P. hordei, 61% of the QTLs for resistance to B. graminis and 47% of the QTLs for non-host resistance to other Puccinia species co-localize with Prx based markers.

Conclusions/significance: We conclude that Prx-Profiling was effective in finding the genetic location of Prx genes on the barley genome. The finding that QTLs for basal resistance to rusts and powdery mildew fungi tend to co-locate with Prx clusters provides a base for exploring the functional role of Prx-related genes in determining natural differences in levels of basal resistance.

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Location of 200 Prx-targeted markers on a high–density integrated map of barley, linkage groups 1H to 4H [22], to be continued in Figure 2.The QTLs were originally mapped in several individual barley linkage maps [13], [14]. Lengths of QTL boxes correspond to the LOD-1 support intervals (from the peak marker) on the basis of results of restricted (r) MQM. Numbers on the left side show the distance in centiMorgans (according to Kosambi) from the top of each chromosome. The red markers correspond to Prx markers mapped in Vada×SusPtrit progenies, the green markers correspond to Prx markers mapped in L94×Vada progenies, and the blue markers correspond to Prx based molecular markers that were available from different sources, such as ESTs. In the cases of different markers matching the same position, the markers are adjacent on the same line. The black markers correspond to the first and the last marker of the linkage group. Different colours of blue inside the chromosome bars correspond to QTL for basal host and non-host resistances that overlapped.
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pone-0010495-g001: Location of 200 Prx-targeted markers on a high–density integrated map of barley, linkage groups 1H to 4H [22], to be continued in Figure 2.The QTLs were originally mapped in several individual barley linkage maps [13], [14]. Lengths of QTL boxes correspond to the LOD-1 support intervals (from the peak marker) on the basis of results of restricted (r) MQM. Numbers on the left side show the distance in centiMorgans (according to Kosambi) from the top of each chromosome. The red markers correspond to Prx markers mapped in Vada×SusPtrit progenies, the green markers correspond to Prx markers mapped in L94×Vada progenies, and the blue markers correspond to Prx based molecular markers that were available from different sources, such as ESTs. In the cases of different markers matching the same position, the markers are adjacent on the same line. The black markers correspond to the first and the last marker of the linkage group. Different colours of blue inside the chromosome bars correspond to QTL for basal host and non-host resistances that overlapped.

Mentions: Nine of the polymorphic bands in the L94×Vada and eight in the Vada×SusPtrit RILs were excluded because they could not be mapped to linkage groups without changing marker order and genetic distances. Finally, 168 polymorphic bands (84 in each population) were mapped and placed on an integrated map of barley [22] (Table S1). These 168 Prx Profiling markers (identified by the label PERO in the marker name, e.g. Figures 1 and 2). were added to 32 Prx markers that were mapped previously [13], [22], and that were considered to be Defense Gene Homologues (DGH). This made a total of 200 Prx-based markers. These were not homogeneously distributed among the seven chromosomes and tended to map in clusters (Figures 1 and 2). Both populations showed a similar distribution of the markers, with the lowest number of Prx Profiling markers for chromosome 4H (4 PERO-markers for Vada×SusPtrit and 1 for L94×Vada). Chromosomes 1H and 7H had the highest number of markers (with 21 PERO-markers on 1H and 16 PERO-markers on 7H for Vada×SusPtrit and 20 PERO-markers on 1H and 15 PERO-markers on 7H for L94×Vada).


Peroxidase profiling reveals genetic linkage between peroxidase gene clusters and basal host and non-host resistance to rusts and mildew in barley.

González AM, Marcel TC, Kohutova Z, Stam P, van der Linden CG, Niks RE - PLoS ONE (2010)

Location of 200 Prx-targeted markers on a high–density integrated map of barley, linkage groups 1H to 4H [22], to be continued in Figure 2.The QTLs were originally mapped in several individual barley linkage maps [13], [14]. Lengths of QTL boxes correspond to the LOD-1 support intervals (from the peak marker) on the basis of results of restricted (r) MQM. Numbers on the left side show the distance in centiMorgans (according to Kosambi) from the top of each chromosome. The red markers correspond to Prx markers mapped in Vada×SusPtrit progenies, the green markers correspond to Prx markers mapped in L94×Vada progenies, and the blue markers correspond to Prx based molecular markers that were available from different sources, such as ESTs. In the cases of different markers matching the same position, the markers are adjacent on the same line. The black markers correspond to the first and the last marker of the linkage group. Different colours of blue inside the chromosome bars correspond to QTL for basal host and non-host resistances that overlapped.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2914007&req=5

pone-0010495-g001: Location of 200 Prx-targeted markers on a high–density integrated map of barley, linkage groups 1H to 4H [22], to be continued in Figure 2.The QTLs were originally mapped in several individual barley linkage maps [13], [14]. Lengths of QTL boxes correspond to the LOD-1 support intervals (from the peak marker) on the basis of results of restricted (r) MQM. Numbers on the left side show the distance in centiMorgans (according to Kosambi) from the top of each chromosome. The red markers correspond to Prx markers mapped in Vada×SusPtrit progenies, the green markers correspond to Prx markers mapped in L94×Vada progenies, and the blue markers correspond to Prx based molecular markers that were available from different sources, such as ESTs. In the cases of different markers matching the same position, the markers are adjacent on the same line. The black markers correspond to the first and the last marker of the linkage group. Different colours of blue inside the chromosome bars correspond to QTL for basal host and non-host resistances that overlapped.
Mentions: Nine of the polymorphic bands in the L94×Vada and eight in the Vada×SusPtrit RILs were excluded because they could not be mapped to linkage groups without changing marker order and genetic distances. Finally, 168 polymorphic bands (84 in each population) were mapped and placed on an integrated map of barley [22] (Table S1). These 168 Prx Profiling markers (identified by the label PERO in the marker name, e.g. Figures 1 and 2). were added to 32 Prx markers that were mapped previously [13], [22], and that were considered to be Defense Gene Homologues (DGH). This made a total of 200 Prx-based markers. These were not homogeneously distributed among the seven chromosomes and tended to map in clusters (Figures 1 and 2). Both populations showed a similar distribution of the markers, with the lowest number of Prx Profiling markers for chromosome 4H (4 PERO-markers for Vada×SusPtrit and 1 for L94×Vada). Chromosomes 1H and 7H had the highest number of markers (with 21 PERO-markers on 1H and 16 PERO-markers on 7H for Vada×SusPtrit and 20 PERO-markers on 1H and 15 PERO-markers on 7H for L94×Vada).

Bottom Line: We examined the association between the Prxs mapped and the QTLs for resistance of barley to homologous and heterologous rusts, and to the barley powdery mildew fungus.We conclude that Prx-Profiling was effective in finding the genetic location of Prx genes on the barley genome.The finding that QTLs for basal resistance to rusts and powdery mildew fungi tend to co-locate with Prx clusters provides a base for exploring the functional role of Prx-related genes in determining natural differences in levels of basal resistance.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Plant Breeding, Wageningen University and Research Center, Wageningen, The Netherlands.

ABSTRACT

Background: Higher plants possess a large multigene family encoding secreted class III peroxidase (Prx) proteins. Peroxidases appear to be associated with plant disease resistance based on observations of induction during disease challenge and the presence or absence of isozymes in resistant vs susceptible varieties. Despite these associations, there is no evidence that allelic variation of peroxidases directly determines levels of disease resistance.

Methodology/principal findings: The current study introduces a new strategy called Prx-Profiling. We showed that with this strategy a large number of peroxidase genes can be mapped on the barley genome. In order to obtain an estimate of the total number of Prx clusters we followed a re-sampling procedure, which indicated that the barley genome contains about 40 peroxidase gene clusters. We examined the association between the Prxs mapped and the QTLs for resistance of barley to homologous and heterologous rusts, and to the barley powdery mildew fungus. We report that 61% of the QTLs for partial resistance to P. hordei, 61% of the QTLs for resistance to B. graminis and 47% of the QTLs for non-host resistance to other Puccinia species co-localize with Prx based markers.

Conclusions/significance: We conclude that Prx-Profiling was effective in finding the genetic location of Prx genes on the barley genome. The finding that QTLs for basal resistance to rusts and powdery mildew fungi tend to co-locate with Prx clusters provides a base for exploring the functional role of Prx-related genes in determining natural differences in levels of basal resistance.

Show MeSH
Related in: MedlinePlus