Lutein esterification in wheat endosperm is controlled by the homoeologous group 7, and is increased by the simultaneous presence of chromosomes 7D and 7Hch from Hordeum chilense

Abstract

The high carotenoid content in tritordeum (×Tritordeum Ascherson et Graebner) grains is derived from its wild parent, Hordeum chilense Roem. et Schulz. Phytoene synthase 1 (Psy1) is located on chromosome 7HchS and plays a major role in this trait. This study investigates the impact of the introgression of chromosome 7Hch into common wheat background on carotenoid composition, including xanthophylls esterified with fatty acids (monoesters and diesters). All of the genetic stocks carrying Psy1 from H. chilense increased their carotenoid content relative to common wheat. In addition, significant changes in the carotenoid profile were detected in different genetic stocks. The most relevant was the increase in content of lutein diesters when both 7Hch and 7D were present, which indicates the existence of genes involved in the esterification of xanthophylls in both chromosomes. Furthermore, our results suggest that 7Hch genes preferentially esterify lutein with palmitic acid, whereas 7D is either indifferent to the fatty acid or it prefers linoleic acid for lutein esterification. The involvement and complementarity of 7Hch and 7D are highly significant considering the scarcity of previous results on lutein esterification in wheat.