RNA-Seq of Early-Infected Poplar Leaves by the Rust Pathogen Melampsora Larici-Populina Uncovers PtSultr3;5, a Fungal-Induced Host Sulfate Transporter

PLoS One. 2012;7(8):e44408. doi: 10.1371/journal.pone.0044408. Epub 2012 Aug 30.


Biotroph pathogens establish intimate interactions with their hosts that are conditioned by the successful secretion of effectors in infected tissues and subsequent manipulation of host physiology. The identification of early-expressed pathogen effectors and early-modulated host functions is currently a major goal to understand the molecular basis of biotrophy. Here, we report the 454-pyrosequencing transcriptome analysis of early stages of poplar leaf colonization by the rust fungus Melampsora larici-populina. Among the 841,301 reads considered for analysis, 616,879 and 649 were successfully mapped to Populus trichocarpa and M. larici-populina genome sequences, respectively. From a methodological aspect, these results indicate that this single approach is not appropriate to saturate poplar transcriptome and to follow transcript accumulation of the pathogen. We identified 19 pathogen transcripts encoding early-expressed small-secreted proteins representing candidate effectors of interest for forthcoming studies. Poplar RNA-Seq data were validated by oligoarrays and quantitatively analysed, which revealed a highly stable transcriptome with a single transcript encoding a sulfate transporter (herein named PtSultr3;5, POPTR_0006s16150) showing a dramatic increase upon colonization by either virulent or avirulent M. larici-populina strains. Perspectives connecting host sulfate transport and biotrophic lifestyle are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Basidiomycota / physiology*
  • Gene Expression Profiling*
  • Gene Expression Regulation, Plant
  • Genes, Plant / genetics
  • Host-Pathogen Interactions / genetics
  • Membrane Transport Proteins / genetics*
  • Membrane Transport Proteins / metabolism
  • Oligonucleotide Array Sequence Analysis
  • Plant Diseases / genetics
  • Plant Diseases / microbiology
  • Plant Leaves / genetics
  • Plant Leaves / microbiology*
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Populus / genetics*
  • Populus / microbiology*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Plant / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sulfates / metabolism
  • Transcriptome / genetics


  • Membrane Transport Proteins
  • Plant Proteins
  • RNA, Messenger
  • RNA, Plant
  • Sulfates

Grant support

This work was founded by grants of the CG Lorraine (France) to S. Duplessis and F. Martin and an INRA innovating grant to S. Duplessis. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Sequencing was supported by the CEA-Genoscope in the frame of a collaborative project. The CEA-Genoscope had no role in the study design, analysis of the data or preparation of the manuscript. The CEA-Genoscope was in charge of 454-data production and collection, and provided agreement on the final version of the manuscript prior publication.