Abstract

Konijeti Rangarajan, Neelam Raman and Srinivasa Prahalad

Phytopthora infestans (Mont.) de Bary, causal organism of late blight disease is referred to as the most destructive specific pathogen of potato (Solanum tuberosum L.). Casualties usually go beyond mere plant destruction, due to its flaring ability to also demolish scientific concerted efforts in establishing novel combat techniques. With high capacity to overcome control measures, it stands at par, and can simply be referred to as a potato-scientist tormentor. This retrospective work examines the role of pathogenesis related proteins and antimicrobial proteins in transgenic potato vis-à-vis P. infestans and prospect for associative introduction and overexpression of synergistically resistance conferring genes as a critical step for developing viable transgenic potatoes. The exploitation of enhanced pathogen-inducible promotor overexpressing key pathogenesis related proteins (PR) exemplified by PR-5 (especially osmotin and thaumatin-like (TL) proteins), PR-12 (defensins such as alfAFP (alfalfa antifungal peptide), Nicotiania megalosiphon defensins (NmDef02)), PR-13 (the thionins); and antimicrobial encoders such as StEREBP1 (Solanum tuberosum ethylene responsive element binding proteins), HEWL (hen egg white lysozyme), CAP (cationic antimicrobial peptide), Barnase cytotoxic protein and oxidative burst through glucose oxidase (GO) have all been incorporated in transgenic potato with variable successes. Apparently, engineering potato with an array of ‘transgenes construct’ of selected pathogenesis related proteins and antimicrobial proteins may provide a chance to terminate both the dissemination of P. infestans and consequent emergence of new strains, terminating the concept of a new agrochemical for P. infestans referred to as ‘oomicides.