Phytophthora infestans-triggered response of growth- and defense-related genes in potato cultivars with different levels of resistance under the influence of nitrogen availability.
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.
Ros
Barbara
B
Department of Plant Sciences, Center for Life and Food Sciences Weihenstephan, Technische Universität München, Am Hochanger 2, 85350 Freising, Germany. barbara.ros@fabi.up.ac.za
Mohler
Volker
V
Wenzel
Gerhard
G
Thümmler
Fritz
F
D018533:Biomass; D002244:Carbon; D002734:Chlorophyll / Q000378:metabolism; D005308:Fertilizers; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D007113:Immunity, Innate / Q000235:genetics* / Q000276:immunology; D009584:Nitrogen / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010838:Phytophthora / Q000502:physiology*; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D011198:Solanum tuberosum / Q000235:genetics* / Q000276:immunology / Q000382:microbiology*
D005308:Fertilizers; D002734:Chlorophyll; D002244:Carbon; D009584:Nitrogen