Genetic and physical characterization of grain texture-related loci in diploid wheat

Abstract

Endosperm texture, i.e. the hardness or softness of the grain, is an important quality criterion in cereals because it determines many grain end-use properties. Grain softness is the dominant trait and is mainly controlled by the Ha locus on the short arm of chromosome 5D in hexaploid bread wheat. Genes for puroindoline a (Pina-D1), puroindoline b (Pinb-D1), and grain softness related protein (Gsp-D1) have been shown to be linked to the Ha locus in dierent mapping populations and have been associated with the expression of grain softness. The study of the linkage relationships among these genes has been limited by the low level of polymorphism in the D genome of hexaploid Triticum aestivum. In the present study, a highly polymorphic Triticum monococcum mapping population was used to analyze linkage relationships among these three genes. Gsp-A m 1 and Pina-A m 1 were found to be completely linked and lie 0.14 cM distal to Pinb-A m 1 in the distal region of the short arm of chromosome 5A m . The tight genetic linkage among these three genes was paralleled by their physical proximity within a single 105-kb clone isolated from a T. monococcum bacterial arti®cial chromosome (BAC) library. A restriction map of this BAC clone showed that Pina-A m

Substitutions and Deletions of Genes Related to Grain Hardness in Wheat and Their Effect on Grain Texture

“…The translocation of the T monococcum segment of chromosome 5A m S in the CS recombinant substitution line was detected with probes for the Gsp‐A m 1 , Pina‐A m 1 , and Pinb‐A m 1 genes using restriction enzyme Hind III These three loci were reported to be present and tightly linked on the distal end of chromosome 5A m in another accession of T monococcum (Tranquilli et al, 1999).…”

“…In order to detect natural deletions at the studied loci, restriction fragment length polymorphism (RFLP) markers were used to characterize the chromosome substitution lines listed above. Nuclear DNA was isolated from leaves, following the procedure described by Dvorak et al (1988) Southern blots and hybridizations were performed as described by Dubcovsky et al (1994) Sample DNAs were digested with Alu I, Bam HI, Bgl II, Dde I, Dra I, Eco RI, Eco RV, Hae III, Hind III, Hinf I, Mbo I, Pvu II, Rsa I, Sty I, Taq I, and Xba I restriction enzymes and screened for polymorphism at Pina‐D1 , Pinb‐D1 , and Gsp‐1 loci with clones pTa31 (Sourdille et al, 1996), pTam19B2 (Tranquilli et al, 1999), and pGsp (Rahman et al, 1994), respectively. Clone pTa31, which corresponds to the Pina‐D1 cDNA, was provided by Dr. P. Joudrier (INRA, Montpellier, France).…”

“…Puroindoline loci, Pina‐D1 and Pinb‐D1 , have been detected only on chromosome 5D, while homoeologous Gsp‐1 loci have been conserved in all the three genomes, on chromosomes 5A, 5B and 5D (Dubcovsky and Dvorak, 1995; Jolly et al, 1996; Sourdille et al, 1996; Giroux and Morris, 1997). Puroindoline genes from chromosomes 5A and 5B are present in the diploid donors of the A and B genomes but have been deleted in polyploid wheats (Tranquilli et al, 1999; Gautier et al, 2000). The Ha ‐related genes may act together to affect grain softness, and it was observed that genotypes having the deletion at Pina‐D1 were harder than those having the single nucleotide mutation in Pinb‐D1 (Giroux et al, 2000).…”

Molecular Markers Linked to Important Genes in Hard Winter Wheat

“…For example, in 2010, dominant stripe rust races overcame some long‐term Yr ‐resistance genes, such as Yr17 . Only a few wheat cultivars, such as Hatcher, TAM 111, Snowmass, Doans, Fannin, and Winterhawk, showed resistance in yield trials of Texas A&M AgriLife Research (Haley et al, 2005, 2011; Lazar et al, 2004; Texas A&M University, 2012). In 2012, however, different predominant stripe rust races caused severe infections on TAM 111, Everest, Snowmass, and Armour, while those cultivars heavily infected in 2010 showed low infection, including several of them carrying Yr17 .…”

Detection of QTLs for bread‐making quality in wheat using a recombinant inbred line population

“…The hardness ( Ha ) locus on chromosome 5D is the main determinant of grain texture in hexaploid wheat. The puroindoline a ( Pina ), puroindoline b ( Pinb ) and grain softness‐related protein ( Gsp‐D1 ) loci are tightly linked at the Ha locus (Tranquilli et al. 1999) and the Ha locus has been sequenced (Chantret et al.…”