Identification and characterization of phytic acid synthesis mutations in oilseed rape

• Applicant: Professor Dr. Christian Jung
• Subject Area: Plant Breeding and Plant Pathology
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 277148037

Phytic acid plays a major role as a phosphate storage compound in plants. While many phytic acid synthesis and transporter genes have been identified in model species as well as in crop species, the corresponding genes from rapeseed, their expression and function are largely unknown. This project aims at the identification of all genes involved in phytic acid synthesis and the isolation of mutants to study gene function. Moreover, those mutants could be beneficial for oilseed rape breeding First, we will perform a comparative sequence analysis of the rapeseed genome to identify all phytic acid synthesis genes that will then be tested for their expression in leaves and seeds.We will focus our studies on phytic acid accumulation in seeds, as high contents of phytic acid in the protein-rich defatted rapeseed meal limit its use in animal and human nutrition.After in silico identification of the genes, we will search an EMS mutagenized winter rapeseed population for missense and nonsense mutations within phytic acid synthesis and transporter genes using a TILLING-by-Sequencing approach. Single mutants will be characterized and crossed among each other to produce low phytic acid double mutants. In a second experiment, mutations within phytic acid synthesis genes will be induced by the CRISPR/Cas9 technique.Selected phytic acid mutants will be further characterized measuring gene expression, enzyme or transporter activity and phytic acid accumulation in developing seeds as well as inositol phosphate intermediates, soluble and total phosphate for phosphate balancing to study metabolic fluxes. Enzyme kinetics measurements after overexpression of rapeseed phytic acid synthesis genes in E. coli will confirm the function of the candidate genes.

• DFG Programme: Research Grants
• Co-Investigator: Dr. Hans-Joachim Harloff