Provided are methods for enhancing plant cell disease resistance, comprising (1) generating a homozygous gene modification of AtSR1 (or AtSR1 ortholog or homolog) in a plant or plant cell characterized by sialic acid-mediated systemic acquired resistance (SA-mediated SAR), wherein said gene modification reduces or eliminates the calmodulin-binding activity of the respective AtSR1 or AtSR1 ortholog or homolog; or (2) expression of a recombinant or mutant AtSR1 sequence (or AtSR1 gene ortholog or homolog sequence) encoding a modified AtSR1, or AtSR1 ortholog or homolog protein, in a plant or plant cell, wherein said protein modification reduces or eliminates the calmodulin-binding activity of the respective AtSR1 or AtSR1 ortholog or homolog protein. Plants and/or plant cells comprising said modified AtSR1, or AtSR1 ortholog or homolog proteins, and/or said expression means (e.g., recombinant expression vector or expressible recombinant and/or mutant sequences), along with nucleic acids encoding said modified proteins are provided.