Screening of the Romanian maize (Zea mays L.) germplasm for crtRB1 and lcyE alleles enhancing the provitamin A concentration in endosperm

Abstract

Maize occupies a significant place in the world agriculture. Yellow kernel maize contains mainly non-provitamin A carotenoids: lutein and zeaxanthin. The accumulation of provitamin A carotenoids is regulated by favourable alleles of lcyE and crtRB1 genes and could be used for the enhancement of these carotenoids in the maize grain through breeding. In this study, molecular screening of the Romanian germplasm was performed, looking for favourable alleles of the crtRB1 and lcyE genes, and the level of carotenoids was determined in a few selected lines. A number of 2746 inbred lines from seven research stations were subjected to a PCR amplification of crtRB1 and lcyE genes in order to identify the favourable alleles. It was selected 27 lines carrying the favourable alleles and nine lines with unfavourable alleles (four groups in total), from which total carotenoids, lutein, zeaxanthin, β-cryptoxanthin, β-carotene and retinol equivalents were determined by HPLC. Out of 2746 inbred lines analysed, 23.53% contained one or both genes with favourable alleles. The favourable allele of the crtRB1 gene was the most widespread (584 lines), followed by the lcyE gene (55 lines), while alleles favourable for both genes were detected in only 7 lines. Inbred lines with the favourable allele of the crtRB1 gene showed the highest levels of β-carotene and β-cryptoxanthin, while those with favourable allele of lcyE gene showed a high level of β-cryptoxanthin; the lines with favourable alleles for both genes had a level of β-carotene 60% higher than the lines with two unfavourable alleles.