Hordeum chilense genome, a useful tool to investigate the endosperm yellow pigment content in the Triticeae

BACKGROUND: The wild barley Hordeum chilense fulfills some requirements for being a useful tool to investigate the endosperm yellow pigment content (YPC) in the Triticeae including its diploid constitution, the availability of genetic resources (addition and deletion stocks and a high density genetic map) and, especially, its high seed YPC not silenced in tritordeums (amphiploids derived from H. chilense and wheat). Thus, the aim of this work was to test the utility of the H. chilense genome for investigating the YPC in the Triticeae. RESULTS: Twelve genes related to endosperm carotenoid content and/or YPC in grasses (Dxr, Hdr [synonym ispH], Ggpps1, Psy2, Psy3, Pds, Zds, e-Lcy, b-Lcy, Hyd3, Ccd1 and Ppo1) were identified, and mapped in H. chilense using rice genes to identify orthologs from barley, wheat, sorghum and maize. Macrocolinearity studies revealed that gene positions were in agreement in H. vulgare and H. chilense. Additionally, three main regions associated with YPC were identified in chromosomes 2H(ch), 3H(ch) and 7H(ch) in H. chilense, the former being the most significant one. CONCLUSIONS: The results obtained are consistent with previous findings in wheat and suggest that Ggpps1, Zds and Hyd3 on chromosome 2H(ch) may be considered candidate genes in wheat for further studies in YPC improvement. Considering the syntenic location of carotenoid genes in H. chilense, we have concluded that the H(ch) genome may constitute a valuable tool for YPC studies in the Triticeae.