The present invention describes an alternative approach to increase GABA production in prokaryotes or eukaryotes, namely by the insertion of the putrescine catabolic pathway in organisms where the pathway does not exist or has not clearly been identified. The invention describes methods for the use of polynucleotides that encode functional putrescine aminotransferase (PAT) and gamma-aminobutyricaldehyde dehydrogenase (GABAlde DeHase) polypeptides in plants to increase GABA production. The preferred embodiment of the invention is in plants but other organisms may be used. Changes in GABA availability will improve growth and increase tolerance to biotic and abiotic stress.