title: Phosphite-induced changes of the transcriptome and secretome in Solanum tuberosum leading to resistance against Phytophthora infestans.
abstract: BACKGROUND
  Potato late blight caused by the oomycete pathogen Phytophthora infestans can lead to immense yield loss. We investigated the transcriptome of Solanum tubersoum (cv. Desiree) and characterized the secretome by quantitative proteomics after foliar application of the protective agent phosphite. We also studied the distribution of phosphite in planta after application and tested transgenic potato lines with impaired in salicylic and jasmonic acid signaling.
  
  
  RESULTS
  Phosphite had a rapid and transient effect on the transcriptome, with a clear response 3 h after treatment. Strikingly this effect lasted less than 24 h, whereas protection was observed throughout all time points tested. In contrast, 67 secretome proteins predominantly associated with cell-wall processes and defense changed in abundance at 48 h after treatment. Transcripts associated with defense, wounding, and oxidative stress constituted the core of the phosphite response. We also observed changes in primary metabolism and cell wall-related processes. These changes were shown not to be due to phosphate depletion or acidification caused by phosphite treatment. Of the phosphite-regulated transcripts 40% also changed with β-aminobutyric acid (BABA) as an elicitor, while the defence gene PR1 was only up-regulated by BABA. Although phosphite was shown to be distributed in planta to parts not directly exposed to phosphite, no protection in leaves without direct foliar application was observed. Furthermore, the analysis of transgenic potato lines indicated that the phosphite-mediated resistance was independent of the plant hormones salicylic and jasmonic acid.
  
  
  CONCLUSIONS
  Our study suggests that a rapid phosphite-triggered response is important to confer long-lasting resistance against P. infestans and gives molecular understanding of its successful field applications.
authors.forename: Dharani Dhar
authors.initials: DD
authors.lastname: Burra
authors.forename: Oliver
authors.initials: O
authors.lastname: Berkowitz
authors.forename: Pete E
authors.initials: PE
authors.lastname: Hedley
authors.forename: Jenny
authors.initials: J
authors.lastname: Morris
authors.forename: Svante
authors.initials: S
authors.lastname: Resjö
authors.forename: Fredrik
authors.initials: F
authors.lastname: Levander
authors.forename: Erland
authors.initials: E
authors.lastname: Liljeroth
authors.forename: Erik
authors.initials: E
authors.lastname: Andreasson
authors.forename: Erik
authors.initials: E
authors.lastname: Alexandersson
mesh_terms: D000613:Aminobutyrates / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D063990:Gene Ontology; D017905:Phosphites / Q000032:analysis / Q000494:pharmacology*; D055750:Phytophthora infestans / Q000502:physiology*; D010935:Plant Diseases / Q000276:immunology*; D057865:Plant Immunity; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011198:Solanum tuberosum / Q000187:drug effects* / Q000235:genetics / Q000276:immunology; D059467:Transcriptome
chemical_list: D000613:Aminobutyrates; D017905:Phosphites; D010940:Plant Proteins; C047667:3-aminobutyric acid