High-Throughput Assay for Measuring Phytate and Available Phosphorus in Ground Maize Seed Samples

Abstract

Phosphorus is an important nutrient for plants and animals. In maize seeds, phosphorus is stored in the form of phytate, which is the phosphorylated form of the sugar inositol. Monogastric animals lack the enzymes required to break phytate down, so it passes through their digestive systems, to create phosphorus-rich waste. This waste contaminates ground water and leads to water quality problems, such as eutrophication, or excessive concentration of nutrients. Phytate reduces the phosphorus available to animals from their feed, requiring animal feed to be supplemented with phosphate. In addition, phytate chelates nutritionally important metal cations, such as iron and zinc, contributing to globally important nutrient deficiencies in human diets. Development of low-phytate corn is an important breeding objective. To achieve this objective, it is crucial to be able to measure phytate, as well as available phosphorus, in maize seeds. Throughout, precision and cost are important considerations in plant breeding programs. This protocol describes methods for quantifying phytate and available phosphorus in maize seeds, in high-throughput 96 well plate assays, suitable for analysis of large-scale field studies and breeding efforts.