Increasing protein content in rice grain using genome engineering
In Rice, High zinc concentration alone is not enough, it also needs to be nutritionally available. Phytic acid ( chemical name: Inositol hexaphoshate; abbreviated PA) through a storage compound, -strongly chelates metal cations including but not limited to P, Fe, Zn, and Ca form phytate ( Sandberg et al., Raboy et al., 2001). Once the food is consumed by humans, the important micronutrients are bound by PA in the intestinal tract to form mixed salts that are mostly excreted. Since phytate reduces the bioavailability of important micronutrients including zinc, iron, and calcium it is considered an anti-nutrient. Enzymatic hydrolysis of grain PA, ( InsP6) by phytase to less phosphorylated inositol phosphates like Inositol pentaphosphate ( InsP5), Inositol tetraphosphate ( InsP4), Inositol triphosphate ( InsP3), Inositol diphosphate ( InsP2) and Inositol monophosphate ( InsP1) is possible during grain storage, germination, food processing and in the gut of human during digestion ( Perera et al.,2018).
Two different approaches will be tried here 1) targeted disabling of specific genes involved in PA synthesis using knowledge of the biochemical pathway. 2) using mutations from other species as a template to modify targeted sites in the rice genome.