Colocation between a gene encoding the bZip factor SPA and an eQTL for a high-molecular-weight glutenin subunit in wheat (Triticum aestivum)

Abstract

The quality of wheat grain is largely determined by the quantity and composition of storage proteins (prolamins) and depends on mechanisms underlying the regulation of expression of prolamin genes. The endosperm-specific wheat basic region leucine zipper (bZIP) factor storage protein activator (SPA) is a positive regulator that binds to the promoter of a prolamin gene. The aim of this study was to map SPA (the gene encoding bZIP factor SPA) and genomic regions associated with quantitative variations of storage protein fractions using F7 recombinant inbred lines (RILs) derived from a cross between Triticum aestivum "Renan" and T. aestivum "Récital". SPA was mapped through RFLP using a cDNA probe and a specific single nucleotide polymorphism (SNP) marker. Storage protein fractions in the parents and RILs were quantified using capillary electrophoresis. Quantitative trait loci (QTLs) for protein were detected and mapped on six chromosome regions. One QTL, located on the long arm of chromosome 1B, explained 70% of the variation in quantity of the x subunit of Glu-B1. Genetic mapping suggested that SPA is located on chromosome arm 1L and is also present in the confidence interval of the corresponding QTL for Glu-B1x on 1BL, suggesting that SPA might be a candidate gene for this QTL.

Rice Metabolomics

“…QTL have traditionally been statistically analyzed by comparison between the genotypes of marker genes and the occurrence of the trait among naturally occurring genetic variants [5,11,27,59]. Recently, transcripotmic information has been used for QTL, which is referred to as expression QTL (eQTL), thereby clarifying the genes directly related to metabolism, such as those coding for enzymes and transporters, and the regulator genes such as the transcription factors [16,40,53,55,56,86]. In addition to transcriptomic data, metabolomic data may be capable of application to QTL analysis.…”

Genomic regions influencing gene expression of the HMW glutenins in wheat

“…Genes controlling expression may be identified in a mapping study that isolates regions of these chromosome arms conferring variation for glutenin protein. Previous investigations have identified the chromosomal location of storage protein regulators (Guillaumie et al 2004;Prasad et al 1999;Colas des Frances and Thiellement 1985). Guillaumie et al (2004) mapped SPA to chromosome group 1L, the same chromosomal arm as the HMW glutenin structural genes.…”

“…Previous investigations have identified the chromosomal location of storage protein regulators (Guillaumie et al 2004;Prasad et al 1999;Colas des Frances and Thiellement 1985). Guillaumie et al (2004) mapped SPA to chromosome group 1L, the same chromosomal arm as the HMW glutenin structural genes. Perretant et al (2000) mapped bread-making quality and identified QTLs for dough strength on chromosomes 5D, 1A and 3B.…”

“…Approaches to the identification and mapping of regulators have included genetic mapping using aneuploid wheat (Galili and Feldman 1985;Rogers et al 1990;Wanous et al 2003) and genetic linkage analysis using wheat populations (Guillaumie et al 2004). Guillaumie et al (2004) genetically mapped SPA to the long arm of chromosome 1B, and Ravel et al (2006) mapped Dof to the long arm of chromosome 5.…”

“…Guillaumie et al (2004) genetically mapped SPA to the long arm of chromosome 1B, and Ravel et al (2006) mapped Dof to the long arm of chromosome 5. Wanous et al (2003) analyzed HMW glutenin proteins in ditelosomic wheat lines, and results indicated genes on several chromosome arms affected the regulation of each glutenin.…”