Quantitative trait loci analysis of phytate and phosphate concentrations in seeds and leaves of Brassica rapa

Phytate, being the major storage form of phosphorus in plants, is considered to be an anti-nutritional substance for human, because of its ability to complex essential micronutrients. In the present study, we describe the genetic analysis of phytate and phosphate concentrations in Brassica rapa using five segregating populations, involving eight parental accessions representing different cultivar groups. A total of 25 quantitative trait loci (QTL) affecting phytate and phosphate concentrations in seeds and leaves were detected, most of them located in linkage groups R01, R03, R06 and R07. Two QTL affecting seed phytate (SPHY), two QTL affecting seed phosphate (SPHO), one QTL affecting leaf phosphate and one major QTL affecting leaf phytate (LPHY) were detected in at least two populations. Co-localization of QTL suggested single or linked loci to be involved in the accumulation of phytate or phosphate in seeds or leaves. Some co-localizing QTL for SPHY and SPHO had parental alleles with effects in the same direction suggesting that they control the total phosphorus concentration. For other QTL, the allelic effect was opposite for phosphate and phytate, suggesting that these QTL are specific for the phytate pathway.