Genetic analysis of Vrn-B1 for vernalization requirement by using linked dCAPS markers in bread wheat (Triticum aestivum L.)

Abstract

To identify a molecular marker closely linked to Vrn-B1, the Vrn-1 ortholog on chromosome 5B, sequence polymorphism at four orthologous RFLP loci closely linked to the Vrn-1 gene family was analyzed by using near-isogenic lines of "Triple Dirk." At Xwg644, a RFLP locus, three types of nucleotide sequence differing by the number of (TG) repeats, two or three times, and base changes were detected. A (TG)(3)-type sequence proved to be specific to chromosome 5B by nulli-tetrasomic analysis, and substitution of single nucleotide (C/T) was detected between TD(B) carrying the former Vrn2 allele and TD(C) carrying the vrn2 allele. A mismatch primer was designed for dCAPS analysis of this single nucleotide polymorphism (SNP). Polymorphism was successfully detected between two NILs, through nested PCR by using a (TG)(3)-specific primer (1st) and a dCAPS primer (2nd) followed by a NsiI digest. The analysis of a BF(2) population [(TD(B)//TD(C)] revealed the close linkage (1.7 cM) between WG644-5B and Vrn2. It was therefore concluded that the former Vrn2 locus is located on chromosome 5B and equivalent to Vrn-B1.

Segregation analysis of heading traits in hexaploid wheat utilizing recombinant inbred lines

“…McIntosh et al (1998) summarized that the previous designations of Vrn2 and Vrn4 were probably the same, or allelic, and then were designated as Vrn-B1 in the new nomenclature system. Recently, Iwaki et al (2002) reported that Vrn2 should be equivalent to Vrn-B1 by analysis using monosomic lines of DwarfA, and identified a molecular marker closely linked to this gene on the long arm of chromosome 5B.…”

Putting genes into genetic coefficients

“…As mentioned previously, Pugsley (1983) and White and Hoogenboom (2003) have suggested that wheat phenology could be largely explained by genes controlling plant height (Rht), photoperiod (Ppd), and vernalization (Vrn). Certainly progress has been made in mapping (Laurie, 1997;Shah et al, 1999;Kato et al, 1999;Sourdille et al, 2000;Iwaki et al, 2002;Toth et al, 2003) and cloning (Danyluk et al, 2003;Peng et al, 1999;Trevaskis et al, 2003;Yan et al, , 2004 these genes. In addition, some of the necessary information on the physiological aspects of these genes may be obtained from other genera.…”

Molecular characterization of the allelic variation at the VRN-H2 vernalization locus in barley

“…Comparative RFLP mapping between wheat and barley has shown that the VRN-1 and VRN-2 genes from these species are orthologous. The VRN-H1 gene has been mapped on the long arm of chromosome 5H in barley, in the same region as the VRN-A1, VRN-B1, and VRN-D1 in wheat (Dubcovsky et al 1998;Barrett et al 2002;Galiba et al 1995;Laurie et al 1995;Iwaki et al 2002;Yan et al 2003). The VRN-H2 gene has been mapped in the distal part of chromosome arm 4HL in barley (Laurie et al 1995) and in the distal part of chromosome arm 5A m L in diploid wheat, in a region translocated from chromosome arm 4A m L (Devos et al 1995;Laurie et al 1995;Dubcovsky et al 1998;Yan et al 2004).…”