November 2017: Carotenoid Genes in Wheat from Colasuonno et al.

Fifteen carotenoid biosynthetic and catabolic genes in wheat coupled with 41 quality-related QTL from Colasuonno et al. has been added to GrainGenes and is available here.
Maps from Wheat AB, Carotenoid QTL, 2017 report loci every ~10 cM and are aligned with the 15 genes with SNPs that segregate in this population and 41 QTL for Grain Yellow Index or Grain Yellow Pigment Content. Work was done on a collection of tetraploid wheat and results were broken out into whole collection vs. durum lines.

Maps reported in this study are subsets of Wheat AB Consensus Maps curated from Maccaferri et al in 2015.

Abstract from Colasuonno et al.
"Background: In plants carotenoids play an important role in the photosynthetic process and photo-oxidative protection, and are the substrate for the synthesis of abscisic acid and strigolactones. In addition to their protective role as antioxidants and precursors of vitamin A, in wheat carotenoids are important as they influence the colour (whiteness vs. yellowness) of the grain. Understanding the genetic basis of grain yellow pigments, and identifying associated markers provide the basis for improving wheat quality by molecular breeding. Results: Twenty-four candidate genes involved in the biosynthesis and catabolism of carotenoid compounds have been identified in wheat by comparative genomics. Single nucleotide polymorphisms (SNPs) found in the coding sequences of 19 candidate genes allowed their chromosomal location and accurate map position on two reference consensus maps to be determined. The genome-wide association study based on genotyping a tetraploid wheat collection with 81,587 gene-associated SNPs validated quantitative trait loci (QTLs) previously detected in biparental populations and discovered new QTLs for grain colour-related traits. Ten carotenoid genes mapped in chromosome regions underlying pigment content QTLs indicating possible functional relationships between candidate genes and the trait. Conclusions: The availability of linked, candidate gene-based markers can facilitate breeding wheat cultivars with desirable levels of carotenoids. Identifying QTLs linked to carotenoid pigmentation can contribute to understanding genes underlying carotenoid accumulation in the wheat kernels. Together these outputs can be combined to exploit the genetic variability of colour-related traits for the nutritional and commercial improvement of wheat products."