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

Abstract

ABSTRACT 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 (PA‐P) 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.