Identification of candidate genes for lutein esterification in common wheat (Triticum aestivum) using physical mapping and genomics tools

Abstract

A high carotenoid content is important for the production of pasta from durum wheat (Triticum durum Desf.) and yellow alkaline noodle from common wheat (T. aestivum L.). Carotenoid esters are more stable than free carotenoid during storage and processing, and thus they allow a higher retention through the food chain. Chromosome 7D carries gene(s) for lutein esterification. The aim of this study was the physical mapping of the gene(s) for lutein esterification on chromosome 7D and the identification of candidate genes for this trait. We developed crosses between a set of deletion lines for chromosome 7D in Chinese Spring (CS) background and the CS–Hordeum chilense substitution line CS(7D)7Hch. The F2 progeny derived from the deletion line 7DS4 produced a lower amount of lutein esters, which indicates that the main gene for lutein esterification is in the region of chromosome 7D lacking in 7DS4. Other gene(s) are contributing to lutein esterification because small amounts of lutein esters are produced in 7DS4. Genotyping by DArTSeq revealed that 7DS4 lacks a 127.7 Mb region of 7DS. A set of 10 candidate genes for lutein esterification was identified by using the wheat reference genome sequence along with the Wheat Expression Browser. This region contains the Lute locus previously identified in a different genetic background. Four genes with acyltransferase or GDSL esterase/lipase activity were identified in the vicinity of Lute. Our results indicate that the gene TraesCS7D01G094000 is a likely candidate for Lute but the gene TraesCS7D01G093200 cannot be ruled out. The candidate genes reported in this work are worthy for further investigation.