Low Phytate crops have reduced levels of phytic acid in seeds with increased amounts of inorganic phosphate. Phytic acid and related metabolites, including inositol, are important in various cellular functions. Little is known concerning low phytic acid (lpa) mutations on gene expression and other cellular processes. Microarray analysis using the Barley1 GeneChip was used to assay gene expression levels over two separate years in developing seeds of M955, a low phytic acid mutation with a 90% reduction in the level of phytic acid. The expression of a total of 11 genes was increased > 2-fold, in both years, in M955-lpa seeds compared with wild-type, and the expression of a total of 63 genes was decreased >2-fold in both years. Interestingly, no large (> 2-fold) changes were observed in the expression of genes related to inositol and phytic acid synthesis. Differences were observed in many genes related to carbohydrate and cell wall metabolism. Pyrophosphatase genes known to be associated with protein storage vacuoles and phytin-containing globoids showed reductions in expression in the M955-lpa genotype, as compared with wild-type. Relative RT-PCR analysis is being conducted to confirm apparent differences in gene expression in various stages of seed development between the 955-lpa and wild-type isolines. These results demonstrate that mutations that block inositol and inositol phosphate metabolism in seeds have downstream impacts on carbohydrate and cell wall polysaccharide. Describing the molecular identity of these impacts will aid in understanding the negative effects of lpa mutations on crop productivity and stress tolerance.