Phytophthora infestans-triggered response of growth- and defense-related genes in potato cultivars with different levels of resistance under the influence of nitrogen availability
Ros. B Mohler. V Wenzel. G Thummler. F
Physiologia Plantarum ; 2008 [Vol.133] Pages:386-396
Abstract
The effects of high and low N concentrations on the Solanum tuberosum–
Phytophthora infestans interaction were studied in the potato cultivars Bettina, New York 121, Indira and Arkula,which exhibited different levels of resistance. Aboveground biomass and Chl and N content were significantly higher in all cultivars grown in higher N environments, while C:N ratios were lower, confirming successful application of N. High availability of N significantly increased susceptibility of three of the four potato cultivars, and amounts of pathogen within the infected leaflets determined in a quantitative real-time reverse transcriptase–polymerase chain reaction reflected this. Differential gene expression of P. infestans- induced and -repressed genes derived from three subtracted cDNA libraries at 0, 24, 48 and 72 h post-inoculation was studied in parallel. P. infestans attack led to an induction of defense-related and at the same time repression of growth-related potato genes mainly encoding photosynthetic genes. High N supply led to higher transcript abundance of photosynthetic genes such as Chl a/b-binding protein and ribulose bisphosphate carboxylase. N-dependent suppression of defense-related compounds in absence of the pathogen was not observed. Better N nutrition appeared to allow the plants to invest more resources in defense reactions.
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