Developing more environmentally friendly and nutritious pea varieties

Abstract

Phytate is the major storage form of phosphorus in crop seeds, but is not well digested by humans and non-ruminant animals. In addition, phytate chelates several essential micronutrients which are also excreted contributing to phosphorus pollution in the environment. Environmental and nutritional concerns led to the development of cultivars with the low phytate trait. The present study is aimed at biochemical and molecular characterization of two low phytate pea mutant lines, 1-150-81 and 1-2347-144 developed at the Crop Development Centre, University of Saskatchewan in collaboration with Dr. Victor Raboy, USDA, Idaho. Biochemical characterization is in progress for the two low phytate lines, their progenitor, CDC Bronco and CDC Meadow that were grown in replicated field trials at Saskatoon and Rosthern, SK in 2010 and 2011. Samples of developing seeds were collected 7 days after pollination and at weekly intervals thereafter until maturity. The concentration of phytate-phosphorus, isomeric forms of phytatephosphorus and inorganic phosphorus in these developing cotyledons and seed coats will be assessed using colorimetric and HPLC methods. In this way, the pattern of phytate-phosphorus and inorganic phosphorus accumulation will be determined in developing seeds. Molecular characterization will include cloning, sequencing and mapping of the gene(s) associated with the low phytate trait. Molecular markers will be developed based on the gene sequences. Recombinant inbred lines (RILs) were developed from crosses between the two low phytate lines and CDC Meadow. One set of RILs was evaluated in a field trial in Saskatchewan in 2011, and will be evaluated again in 2012. The RILs will be genotyped using available microsatellite markers or SNP markers and phenotyped using colorimetric and HPLC assays. These data will then be used to identify the molecular marker(s) for the trait. The study will aid us to understand the nature of the low phytate mutation(s). Significant potential benefits that we could expect out of the project include improved bioavailability of phosphorus, iron and zinc in foods and feeds, less phosphorus excretion and environmental pollution and a substantial saving in feed costs.