News & events

IFAPA-CICE (Junta de Andalucia),
CIFA Alameda del Obispo,
Apdo. 3092,
14080 Cordoba,
Spain

Mini-biography
Dr Ana Maria Torres has been a research scientist at the Breeding and Biotechnology Department (IFAPA, Córdoba, Spain) since 1991. Her laboratory's interests are focused on classical breeding, disease resistance studies and use of molecular markers for mapping purposes and tagging genes of interest in legumes. Concerning field bean, the group has developed the only genetic maps available so far in the species. Most of the efforts of the group have been focussed on resistance to broomrape, Ascochyta fabae, Uromyces viciae-fabae as well as several yield components by identifying resistant/tolerant germplasm, determining the genetics of the traits and the map positions of the genes and QTLs of interest. Besides, some nutritional aspects, such as low content of tannins and vicine-convicine have been also addressed and molecular markers useful for MAS are already available.


Molecular markers for breeding disease resistance in pea, chickpea and faba bean
Ana M. Torres
IFAPA, Centro "Alameda del Obispo" ; Área de Mejora y Biotecnología; Avda. Menéndez Pidal s/n; Apdo. 3092; 14080 Córdoba, SPAIN
anam.torres.romero@juntadeandalucia.es

The potential benefits of using markers linked to genes of interest in breeding programmes have been obvious for many decades. Molecular markers allow high-density DNA marker maps to be constructed, thus providing the framework needed for eventual applications of MAS (Marker-Assisted Selection). Using the maps, putative genes affecting traits of interest can be detected by testing for statistical associations between markers variants and any trait of interest. These traits might be genetically simple as many disease resistance traits in plants, which are controlled by one or a few genes. Alternatively, they could be genetically complex quantitative traits, involving many genes, so-called quantitative trait loci (QTLs), and environmental effects. Most economically important agronomic traits tend to fall into the second category. Having identified markers physically located beside, or even within, genes of interest, it is now possible in the next step, to carry out MAS, i.e. to select identifiable marker variants (alleles) in order to select for non-identifiable favourable variants of the genes of interest. In this talk we provide a brief summary of the current status regarding genetic improvement of faba bean, chickpea and pea against several important biotic stresses.

Molecular breeding of faba bean (Vicia faba) for disease resistance, particularly for resistance to rust, broomrape and Ascochyta, is one of the main targets of our group and promising results have been obtained (Román 2002; 2003; Avila 2003; 2004). QTLs controlling resistance to broomrape and to Ascochyta blight have been identified and their stability in different environments and populations assessed. The use of MAS is possible not only by locating a gene of interest in a map, but also by flanking the gene with tightly linked, densely saturated markers. This process termed “fine mapping” has also been undertaken by our group to develop reliable markers for MAS (see a review in Torres et al. 2006).

Concerning chickpea (Cicer ssp.), the two more important biotic stresses are fusarium wilt and ascochyta blight. Other diseases like rust can be important in some environmental conditions. We have developed molecular markers tightly linked to one gene conferring resistance to fusarium wilt race zero (Foc0/foc0) (Cobos et al., 2005) and to 2 QTLs, related to resistance to ascochyta blight (Iruela et al. 2006; Iruela et al., in press).

In pea (Pisum ssp.), 2 SCAR markers linked to Er3 (one of the 3 resistant genes conferring resistance to powdery mildew described so far) have recently been developed. The validation for polymorphism in different genetic backgrounds and advanced breeding material confirmed the utility of these SCAR markers for MAS. In addition to this, molecular markers flanking QTLs controlling resistance to Mycosphaerella pinodes have recently been identified (Fondevilla PhD thesis). Finally, the study of an F2 population between 2 P. fulvum accessions segregating for resistance to rust has recently allowed the detection of 1 QTL explaining more than 60% of the phenotypic variation of the trait (Barilli PhD thesis).
The information obtained so far will facilitate the strategy for gene pyramiding and the future development of lines and cultivars with multiple traits of interest in these legume species.

Avila CM, Sillero JC, Rubiales D, Moreno MT, Torres AM (2003) Identification of RAPD markers linked to Uvf-1 gene conferring hypersensitive resistance against rust (Uromyces viciae-fabae) in Vicia faba L. Theor Appl Genet 107 (2): 353-358.

Avila CM, Satovic Z, Sillero JC, Rubiales D, Moreno MT, Torres AM (2004) Isolate and organ-specific QTLs for ascochyta blight resistance in faba bean. Theor. Appl. Genet. 108: 1071-1078.

Cobos, M.J.; M.J. Fernández; J. Rubio; M. Kharrat; M.T. Moreno; J. Gil, T. Millán. 2005. A linkage map in chickpea (Cicer arietinum L.) in two populations from Kabuli x Desi crosses: location of a resistance gene for fusarium wilt race 0. Theoretical and Applied Genetics 110:1347-1353.

Fondevilla S, Rubiales D, Moreno MT and Torres AM. Identification and validation of RAPD and SCAR markers linked to the gene Er3 conferring resistance to Erysiphe pisi DC in pea (submitted)

Iruela, M., J. Rubio, F. Barro, J.I. Cubero, T. Millan, J. Gil, 2006. Detection of two QTL for resistance to Ascochyta Blight in an intraspecific cross of chickpea (Cicer arietinum L.): Development of SCAR markers associated to resistance. Theor Appl Genet 112: 278–287.

Iruela, M., P Castro, J. Rubio, J.I. Cubero, C. Jacinto, T. Millan, J. Gil. 2007. Validation of a QTL for resistance to ascochyta blight linked to resistance to fusarium wilt race 5 in chickpea (Cicer arietinum L.) European Journal of plant pathology. In press

Roman B, Torres AM, Rubiales D, Cubero JI, Satovic Z (2002) Mapping of quantitative trait loci controlling broomrape (Orobanche crenata Forsk.) resistance in faba bean (Vicia faba L.). Genome 45: 1057-1063.

Roman B, Satovic Z, Avila CM, Rubiales D, Moreno MT, Torres AM (2003) Locating genes associated with Ascochyta fabae resistance in Vicia faba L. Aust J Agric Res 54 (1): 85-90.

Torres AM, Román B, Avila CM, Satovic Z, Rubiales D., Sillero JC, Cubero JI, Moreno MT(2006) Faba bean breeding for resistance against biotic stresses: towards application of marker technology. Euphytica 147: 67–80


Molecular markers linked to loci controlling low tannin, vicine and convicine contents in faba bean
Ana Maria Torres
IFAPA, Centro "Alameda del Obispo"; Área de Mejora y Biotecnología; Avda. Menéndez Pidal s/n; Apdo. 3092; 14080 Córdoba, SPAIN
anam.torres.romero@juntadeandalucia.es

Molecular markers linked to desired traits are valuable tools for efficient selection of genotypes of interest. These markers allow precocious screening to be performed directly on DNA extracted from young leaves without waiting for the specific developmental stage at which the trait is expressed (e.g. flower colour or complete seed ripeness in case of tannins, or vicine and convicine (v-c), respectively).
Here, we aimed to develop markers tightly linked to loci controlling low tannin and v-c contents in faba bean for reliable and rapid screening of segregating populations.

Three F2 populations involving lines with zero tannin genes (zt-1, y, zt-2) and with the zero vicine-convicine mutant (vc- = line 1268) have been analysed. Bulked Segregant Analysis (BSA) (Michelmore et al., 1991) was used to identify linked Random Amplified Polymorphic DNA (RAPD) markers. The RAPD fragments associated with tannin and v-c content were transformed into more consistent PCR-based markers, the Sequence-Characterised Amplified Regions (SCAR) (Paran and Michelmore, 1993). When the SCARs were monomorphic, i.e. producing similar DNA fragments in both high and low tannin or v-c content plants, restriction enzyme digestion was performed in order to develop CAPS (Cleaved Amplified Polymorphic Sequences) markers able to differentiate the two genotypes thanks to a polymorphism of restriction site.

Following this procedure, we developed two CAPS markers linked in coupling and repulsion phase to the allele vc- (Gutierrez et al., 2006) and one SCAR marker allowing the prediction of zt-1 genotypes with 95% accuracy (Gutierrez et al., 2007). In addition to these published data, we will present our latest unpublished data on the development of new molecular markers allowing the prediction of zt-2 genotypes with 85% accuracy (Gutierrez, personal communication).

These markers can be used in MAS to introgress the appropriate alleles to develop cultivars with low v-c content and improved nutritional value, thus avoiding the cost and difficulties associated with the chemical determination of these products.

Gutierrez N, C.M. Avila, G. Duc, P. Marget, M.J. Suso, M.T. Moreno and A.M. Torres (2006). CAPS markers to assist selection for low vicine and convicine contents in faba bean (Vicia faba L.). Theoretical and Applied Genetics (2006) 49:1227-1237

Gutierrez N, C.M. Avila, C Rodriguez-Suarez, M.T. Moreno and A.M. Torres (2007). Development of SCAR markers linked to a gene controlling absence of tannins in faba bean. Molecular Breeding (in press).

Michelmore R, Paran I, Keselli V (1991). Identification of markers linked to disease-resistance genes by bulk segregant analysis: A rapid method to detect markers in specific genomic regions by using segregating populations. Proc Natl Acad Sci USA 88: 9828-9832.

Paran I, Michelmore R (1993). Development of reliable PCR-based markers linked to downy mildew resistance genes in lettuce. Theor Appl Genet 85: 985-993.

Tanksley SD, Young ND, Paterson AH, Bonierbale MW (1989). RFLP mapping in plant breeding: New tools for an old science. Bio/Technology 7: 257-264.