AUTHOR=Sashidhar Niharika , Harloff Hans J. , Jung Christian 

TITLE=Knockout of MULTI-DRUG RESISTANT PROTEIN 5 Genes Lead to Low Phytic Acid Contents in Oilseed Rape

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00603

DOI=10.3389/fpls.2020.00603

ISSN=1664-462X

ABSTRACT=<p>Understanding phosphate uptake and storage is interesting to optimize the plant performance to phosphorus fluctuations. Phytic acid (PA) is the major source of inorganic phosphorus (Pi) in plants. Genetic analyses of PA pathway transporter genes (<italic>BnMRP5</italic>) and their functional characterization might provide clues in better utilizing the available phosphate resources. Furthermore, the failure to assimilate PA by monogastric animals results in its excess accumulation in manure, which ultimately causes groundwater eutrophication. As a first step toward breeding low PA mutants in oilseed rape (<italic>Brassica napus</italic> L.), we identified knockout mutants in PA biosynthesis and transporter genes. The obtained M<sub>3</sub> single mutants of <italic>Bn.MRP5.A10</italic> and <italic>Bn.MRP5.C09</italic> were combined by crossing to produce double mutants. Simultaneously, crosses were performed with the non-mutagenized EMS donor genotype to reduce the background mutation load. Double mutants identified from the F<sub>2</sub> progeny of direct M<sub>3</sub> crosses and BC<sub>1</sub> plants showed 15% reduction in PA contents with no significant differences in Pi. We are discussing the function of <italic>BnMRP5</italic> paralogs and the benefits for breeding <italic>Bnmrp5</italic> mutants in respect to low PA, yield, and stress tolerances.</p>