The impact of cross-breeding two low phytic acid (lpa) rice mutants on the content of phytic acid and the metabolite profile of the resulting double mutant was investigated. Progenies resulting from the cross of Os-lpa-XS110-1, a rice mutant carrying the myo-inositol kinase (OsMIK) mutated gene, and Os-lpa-XS110-2, with the multidrug resistance-associated protein ABC transporter gene 5 (OsMRP5) as the mutation target, were subjected to high-pressure ion chromatography. The reduction of the phytic acid content in the double mutant (-63%) was much more pronounced than in the single mutants (-26 and -47%). Gas chromatography-based metabolite profiling revealed a superimposition of the metabolite profiles inherited from the lpa progenitors in the double mutant progenies; the resulting metabolite signature was predominated by the OsMIK mutation effect. The study demonstrated that cross-breeding of two single lpa mutants can be employed to generate double lpa rice mutants showing both a significant reduction in the content of phytic acid and the imprinting of a specific mutation-induced metabolite signature.
Keywords: cross-breeding; double mutant; low phytic acid mutant; metabolite profiling; rice (Oryza sativa L.).