Potato, as a cheap and energetic source of calories, is always one of the most important crop in the word and one of the fifteen nutrient which secure 90% of human nutritional requirement . One of the most important potato yield reducing factor is various fungal diseases such as old and well known potato and tomato disease which called "potato and tomato ring spot". The disease, which is due to several fungal species of Alternaria Nees genus, invade and destroys every years great deal of potato and tomato production. Following pathogen invasion, plant defense system will stimulate expression of diverse proteins in plant such as thaumatin-like proteins as a pathogenesis related proteins. This protein which belong to fifth group of 17 groups of pathogenesis related proteins, stimulate their expression with divers inducer such as different pathogens and stressful factors. Thaumatin like proteins possess different impasive activities which one of the most important is anti fungal activity. This propety would be a suitable tool in breeding activities. Some of the coding genes of this kind proteins such as TLP-3 gene is currently known. In this research in order to reducing chemical pesticides usage and enhance the resistance of potato crop against invading ring spot pathogen, the gene transfer to potato genome by Agrobacterium-mediated system. Considering the important role of optimizing tissue culture condition in success of transformation process, at first different factor of tissue culture optimized and appropriate variety and hormone mixture was selected. The selected variety were transformed by the Gram-negative soil phytopathogen Agrobacterum tumefaciens which carrying TLP-3 gene construct subsequently. The explants were regenerated in selective medium with the most appropriate hormone mixture. The regenerated plants which grow up in selective mediums, their transformation was proofed by polymerize chain reaction (PCR), reverse transcriptase polymerize chain reaction (RT-PCR) and fungal spore of ring spot generation and growth tests in media which contain transformed and untransformed plant extraction. In order to check signal peptide influence on antifungal activity of the protein, bioassay in greenhouse and inter and intra cellular protein extraction is necessary, so it is not possible to judge in this issue with the data. The results, in addition of proofing the antifungal TLP’s activity, have implied that the explant have the least influence on plant regeneration while genotype and hormone mixture in regeneration medium have greet influences on regeneration yield. It should be noticed that hormone mixture has the most important effect among the variety were studied in this research. According to the results, potato regeneration yield in medium contain high amount of cytokines with low level of axine is the best. Furthermore the most important factor in potato regeneration is callus quality not quantity