Mapping Seed Phytic Acid Concentration and Iron Bioavailability in a Pea Recombinant Inbred Line Population

Phytate, the storage form of P in seeds, is not well digested by monogastrics, thereby contributing to micronutrient deficiency, decreased feed efficiency, and environmental pollution. This research was aimed at developing a single nucleotide polymorphism (SNP) based genetic linkage map and mapping genomic regions associated with phytic acid-phosphorus (PAP) concentration using a recombinant inbred line (RIL) population (PR-15) derived from a cross between a low phytate (low phytic acid [lpa]) mutant pea (Pisum sativum L.) genotype, 1-2347-144, and a normal phytate cultivar CDC Meadow. A total of 163 RILs were genotyped using a 1536-SNP Illumina GoldenGate array. Three hundred and sixty-seven polymorphic SNP markers ordered into seven linkage groups (LGs) were used to generate a linkage map with a total length of 437.2 cM. PR -15 lines were grown in replicated field trails in Saskatoon and Rosthern, SK, in 2012 and 2013. Chi-square statistics confirmed the single gene inheritance of PA-P concentration in these RILs. Phytic acid-phosphorus (PA-P) phenotype was mapped to LG5. Iron bioavailability (FEBIO) of PR -15 lines estimated using the Caco-2 cell culture bioassay was negatively correlated with PA-P concentration. A quantitative trait locus (QTL) for FEBIO was mapped on to the same location on LG5 as phytic acid concentration. The QTL with a maximum LOD score of 15.1 explained 60.5% of the phenotypic variation in FEBIO. The markers flanking this QTL region can be employed in marker-assisted selection to select pea lines with low phytate and greater Fe bioavailability.