Development of low-phytate maize inbred lines through marker-assisted introgression of lpa1

Abstract

Context. Phytic acid is the major storage form of phosphorus in cereals and is considered an antinutritional factor because it chelates major mineral micronutrient cations, resulting in micronutrient malnutrition in humans. For monogastric animals fed maize (Zea mays L.) grains, the stored phosphorus does not release into the digestive tract, leading to phosphorus deficiency and environmental pollution. Aims. The aim of the study was to develop maize lines with a lower level of phytic acid that might substantially enhance the nutritional value of maize. Methods. The lpa1 mutant allele conferring low phytic acid was transferred into the parental lines of popular maize hybrid DMH 121 (i.e. BML 6 and BML 45) through marker-assisted backcross breeding. Foreground selection was performed using a co-dominant single nucleotide polymorphism marker through a high-resolution melting approach, and background selection was undertaken using 50–55 polymorphic sequence-tagged microsatellite site markers. Key results. Near-isogeneic lines were produced with >90% recurrent parental genome and reduction of phytic acid content by up to 44–56% compared with the original lines. Conclusions. The near-isogeneic lines carrying lpa1 can be used to reconstitute DHM 121 with low phytate content. Implications. The low-phytate maize hybrids produced can be useful in reducing micronutrient malnutrition in humans, as well as environmental pollution.