Functional Residues in Plant Nutrient Transporters: An Opportunity for Gene Editing to Improve Agronomic Traits

Plants require essential nutrients for maintaining normal physiological, biochemical, and molecular functions. Plasma membrane-localized nutrient transporters play key roles in acquiring and allocating plant nutrients. Extensive studies have been performed on the functional characterization of key plant nutrient transporters in the past decades. Crystal structures of a few plant nutrient transporters and bacterial or fungal homologs were solved, which helped to predict the key residues and transport mechanisms of plant nutrient transporters. Site-directed mutagenesis and yeast complementation studies have also identified functional residues. This review presents a comprehensive list of the functional residues of various macro- and micro-nutrient transporters involved in acquiring and redistributing nutrients in the plant. We have also analyzed the functionally important residues of various plant nutrient transporters with bioinformatics tools. We then draw insights on the possible application of CRISPR/Cas tools to edit key residues to improve nutrient transport and agronomical performance. Utilization of genome editing tools like CRISPR could help develop DNA-free GM crops for quicker approval for field cultivation, contributing to food security amidst global climate change.