RAPD and SCAR markers linked to resistance to frogeye leaf spot in soybean

Abstract

The soybean (Glycine max (L.) Merrill) frogeye leaf spot is caused by the fungus Cercospora sojina Hara and is a widespread disease in Brazil and other countries, causing severe losses in grain yield and also affecting seed quality. The availability of DNA markers linked to genes for resistance to this disease would accelerate breeding programs, particularly when other traits are also being evaluated. Bulked segregant analysis was applied to 3 F 2 populations derived from crosses between the resistant cultivars Parana, Cristalina and Uberaba, and the susceptible cultivar Bossier. In the cross 'Parana' x 'Bossier', 2 RAPD markers were identified, CSOPA1 800C and CSOPA2 1,250C , located at 4.4 ± 1.8 centiMorgans (cM) and 3.4 ± 1.7 cM respectively from the resistance locus. DNA fragments of similar molecular weight were observed in the population derived from the cross 'Cristalina' x 'Bossier' at 2.3 ± 1.2 and 4.7 ± 1.5 cM from the resistance locus, respectively. In the offspring of the cross 'Uberaba' x 'Bossier', a DNA fragment corresponding to marker CSOPA1 800C was detected at 5.6 ± 2.1 cM from the resistance locus. Although marker CSOPA2 1,250C was not observed in this population, an additional marker was detected (CSOUB1 1,100C ) at 6.7 ± 2.2 cM from the resistance locus. The 1,250 bp fragment of CSOPA2 1,250C was cloned and converted into a SCAR marker, which amplified a single fragment whose size corresponded to the cloned segment of the crosses involving cultivars Cristalina and Parana. Markers CSOPA1 800C , CSOPA2 1,250C and CSOUB1 1,100C were mapped to soybean linkage group J with the aid of known SSRs linked to the Rcs3 locus, indicating that the RAPD and SCAR markers identified in our research also tag this resistance gene.

Marcadores RAPD para detecção de resistência à ferrugem-asiática-da-soja

“…Diversos estudos identifi caram marcadores RAPD ligados a genes de resistência a patógenos em várias culturas, entre eles: resistência ao nematóide-de-cistoda-soja, à mancha olho-de-rã, ao míldio e ao cancroda-haste em soja (Heer et al, 1998;Carvalho et al, 2002;Chowdhury et al, 2002;Martins Filho et al, 2002;Gavioli et al, 2007); resistência à manchaangular em feijoeiro (Ferreira et al, 1999); resistência à brusone em arroz (Araújo et al, 2004 Garcia et al (2008).…”

Molecular Markers: Assisted Selection in Soybeans

“…It is expected that with advances in functional genomics projects, some markers will lose its practical application, because knowing the sequence of the allele, the job is much more accurate. Martins Filho et al (2002) used the technique BSA, in a survey of three F 2 populations of soybean exhibiting resistance to the fungus Cercospora sojina. The authors have built on resistant and susceptible groups, with six plants in each one of them and were able to identify RAPD markers in three populations.…”

“…The process resulted in the loss of polymorphism, which was resolved by digesting the fragments with the enzyme HincII (Figure 2 There are numerous studies to obtain SCAR markers linked to disease resistance of crops. In soybean there are the surveys conducted by Heer et al (1998) who worked with resistance to soybean cyst nematode; Martins Filho et al (2002), in studies on resistance to the fungus Cercospora sojina; Zheng et al (2003) in relation to the mosaic virus and Carvalho et al (2002) in the evaluation of soybean plants resistant to stem canker.…”

Identificação de marcador RAPD e SCAR relacionados ao caractere florescimento precoce em <i>Eucalyptus grandis</i>.

“…O desenvolvimento de SCARs (Paran e Michelmore, 1993) pode ser utilizado na seleção assistida para resistência a doenças, mapeamento de genes de interesse e identificação de cultivares, entre outras finalidades (Nietsche et al, 2000;Martins Filho et al, 2002;Rameau et al, 1998;Tar'an et al, 2003).…”