Phosphite-induced changes of the transcriptome and secretome in Solanum tuberosum leading to resistance against Phytophthora infestans

Abstract

BackgroundPotato 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.ResultsPhosphite 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.ConclusionsOur 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-014-0254-y) contains supplementary material, which is available to authorized users.

Plant Resistance Inducers against Pathogens in Solanaceae Species—From Molecular Mechanisms to Field Application

“…In potato it has been reported that phosphite leads to excessive accumulation of hydrogen peroxide and PR1 transcripts [80], which is associated with SA signaling. A time-course study of phosphite applications in potato by genome-wide microarrays did not detect up-regulation of PR1 transcripts, even if phosphite caused a major, but transient, change of the transcriptome within 24 h [75]. Instead, genes associated with defense, wounding and oxidative stress were found to constitute the core of the phosphite response, together with changes in primary metabolism and cell wall-related processes.…”

“…Instead, genes associated with defense, wounding and oxidative stress were found to constitute the core of the phosphite response, together with changes in primary metabolism and cell wall-related processes. Interestingly, there was an overlap of 40% between phosphite- and BABA-regulated transcripts, indicating that similar processes are affected upon induction of resistance even though the effect of BABA on the transcriptome lasts longer and goes on for at least 48 h [11,75]. In a study of soluble proteins from potato leaves treated with the phosphite product Confine™, Lim et al [77] found increased abundance of proteins involved in SA-dependent defense responses, reactive oxygen species (ROS) and calcium-dependent pathways, whereas proteins involved in amino acid and starch metabolism were down-regulated.…”

Achievements and prospects of applying high-throughput sequencing techniques to potato genetics and breeding

“…Этот ресурс Европейского института биоинформатики содержит результаты 77 экс периментов по анализу экспрессии генов картофеля (Ali et al, 2014;Burra et al, 2014). Основные типы экспери ментов, данные по которым опубликованы в ArrayExpress для S. tuberosum, это высокопроизводительное секвени рование транскриптома ('RNAseq of coding RNA', 9 экс периментов) и анализ экспрессии с помощью микрочипов ('transcription profiling by array', 62 эксперимента).…”

Metabolomics Profile of Potato Tubers after Phosphite Treatment

“…Although several studies have reported the negative effects of Phi on the growth of plants [64]- [69], its mode of action at the molecular level is not fully understood [23] [70]. Even though the proteomic analysis [9], transcriptomic profiling [24] and high-performance ion chromatography (HPIC) method [10] have been used for assessing the accumulation of Phi in potato tubers, a detailed study of metabolite changes in response to Phi can increase our understanding of plant defense responses, interactions between metabolic networks and basic plant metabolism. Metabolomics is a powerful approach to gain a comprehensive perspective of how metabolic networks are regulated and has increasingly been applied by many researchers in recent years.…”

“…Lovatt and Mikkelsen [63] also reported that Phi may influence sugar metabolism, cause internal hormonal and chemical changes, and induce the SA pathway, resulting in increased floral intensity, and fruit yield and quality in various crops including onions, potatoes and tomatoes. Burra et al [24] investigated transcriptome analysis of potatoes after Phi treatment and found that transcripts associated with defense, wounding, and oxidative stress constituted the core of the Phi response. They also observed changes in primary metabolism and cell wall related processes.…”