Comparative Nutritional Assessment and Metabolomics of a WRKY Rice Mutant with Enhanced Germination Rates

Abstract

Rice is the primary staple food for half the world’s population. Climate change challenges and food insecurity supports the need for rice with agronomically advantageous traits. We report on a transposon insertional rice mutant with enhanced germination rates. This trait is advantageous for rice growth in limited water regions and to reduce yield constraints caused by weed and bird competition. Evaluations of vital nutritional components, compositional analysis, and comparative metabolomics on threshed grain samples are performed, as these assays are those used to assess the safety of foods from genetically modified crops. Compared with the wild type (cv. Nipponbare), oswrky71 mutant grains have a similar size, shape, amount of crude fiber, crude fat, and ash content but higher crude protein. Mineral analyses reveal higher contents of phosphorus and zinc but lower calcium, potassium, sodium, and manganese in the mutant. Analysis of B vitamins reveals significantly higher riboflavin concentrations but lower choline chloride, calcium pantothenate, and thiamine. In addition, untargeted metabolomics analyses identify approximately 50 metabolites whose levels differed between the mutant and its wild type. Physical traits and compositional parameters analyzed are mostly similar and within the range or very close to being considered safe for consumption by the International Life Sciences Institute Crop Composition Database. Further agronomic evaluation and cooked rice sensory properties assessment are needed before positioning this mutant for human consumption.