Revealing the importance of meristems and roots for the development of hypersensitive responses and full foliar resistance to Phytophthora infestans in the resistant potato cultivar Sarpo Mira

• Published in: Journal of experimental botany Vol. 63; no. 13; pp. 4765 - 4779
• Main Authors: Orłowska, Elżbieta, Basile, Alessio, Kandzia, Izabela, Llorente, Briardo, Kirk, Hanne Grethe, Cvitanich, Cristina
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press [etc.] 01.08.2012; Oxford University Press
• Subjects: Agronomy. Soil science and plant productions; Anti-Infective Agents - chemistry; Anti-Infective Agents - pharmacology; antimicrobial agents; antimicrobial properties; Biological and medical sciences; cultivars; Disease Resistance; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Gene Expression Regulation, Plant - genetics; genes; Genetics and breeding of economic plants; hypersensitive response; leaves; Meristem - chemistry; Meristem - genetics; Meristem - immunology; Meristem - parasitology; meristems; Models, Biological; pathogens; Phytopathology. Animal pests. Plant and forest protection; Phytophthora infestans; Phytophthora infestans - pathogenicity; Plant Diseases - immunology; Plant Diseases - parasitology; plant extracts; Plant Extracts - chemistry; Plant Extracts - pharmacology; Plant Leaves - chemistry; Plant Leaves - genetics; Plant Leaves - immunology; Plant Leaves - parasitology; Plant physiology and development; Plant Proteins - genetics; Plant Roots - chemistry; Plant Roots - genetics; Plant Roots - immunology; Plant Roots - parasitology; Plant Shoots - chemistry; Plant Shoots - genetics; Plant Shoots - immunology; Plant Shoots - parasitology; potatoes; Research Paper; roots; shoots; Signal Transduction; Solanum tuberosum - chemistry; Solanum tuberosum - genetics; Solanum tuberosum - immunology; Solanum tuberosum - parasitology; Plant pathogen; Mycosis; Potato; Dicotyledones; Angiospermae; Botany; Development; Phytophthora infestans; Solanaceae; Stramenopila; Hypersensitive response; late blight; Root; Solanum tuberosum; Hypersensitivity; Sarpo Mira; Plant leaf; Oomycota; Meristem; Infection; Resistance; Spermatophyta; Tuber plant; plant signalling; Cultivar
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/ers154

The defence responses of potato against Phytophthora infestans were studied using the highly resistant Sarpo Mira cultivar. The effects of plant integrity, meristems, and roots on the hypersensitive response (HR), plant resistance, and the regulation of PR genes were analysed. Sarpo Mira shoots and roots grafted with the susceptible Bintje cultivar as well as non-grafted different parts of Sarpo Mira plants were inoculated with P. infestans. The progress of the infection and the number of HR lesions were monitored, and the regulation of PR genes was compared in detached and attached leaves. Additionally, the antimicrobial activity of plant extracts was assessed. The presented data show that roots are needed to achieve full pathogen resistance, that the removal of meristems in detached leaves inhibits the formation of HR lesions, that PR genes are differentially regulated in detached leaves compared with leaves of whole plants, and that antimicrobial compounds accumulate in leaves and roots of Sarpo Mira plants challenged with P. infestans. While meristems are necessary for the formation of HR lesions, the roots of Sarpo Mira plants participate in the production of defence-associated compounds that increase systemic resistance. Based on the literature and on the presented results, a model is proposed for mechanisms involved in Sarpo Mira resistance that may apply to other resistant potato cultivars.