Enhancement of tocopherols in sweet corn by marker-assisted backcrossing of ZmVTE4

Vitamin E is a group of lipid-soluble antioxidants, which is indispensable and unable to be biosynthesized by the human body. Sweet corn is one of the most popular vegetables and important vitamin E resource for human. In this study, one common corn line with favorable allele on the InDel7 (deletion) and InDel118 (deletion) sites in the locus of ZmVTE4 (SY999) was introduced as the donor parent line, 4 elite sweet corn lines were selected as the recipient lines. The ZmVTE4 gene was introgressed into 4 sweet corn lines by functional molecular marker assisted selection. Two flanking SSR markers were selected to reduce the linkage drag. Few agronomic traits were investigated in the BC1F1 and BC2F1 generations and some individuals differing from the recurrent parents had been abandoned. The investigation of few agricultural traits showed no difference between the converted lines and their recipient lines. Five selected BC3F2 families per backcross progenies and their recurrent parent lines were sown to measure the content of tocopherols. The quantification showed that the alpha-tocopherol content of three backcross progenies increased except for M14. The introduction of ZmVTE4 gene also improved the content of gamma-tocopherol and total tocopherols content. The average content of gamma-tocopherol and total tocopherols content were 29.11 and 36.63 mu g/g in the four selected elite sweet corn lines and the average content in the four converted lines were 51.45 and 63.34 mu g/g. This result indicated that ZmVTE4 had different expression in the sh (2) genetic background or the non-target genome introgression into the recipient parent lines affecting the content of tocopherols.