cell- and tissue-specific transcriptome analyses of Medicago truncatula root nodules

PLoS One. 2013 May 29;8(5):e64377. doi: 10.1371/journal.pone.0064377. Print 2013.

Abstract

Legumes have the unique ability to host nitrogen-fixing Rhizobium bacteria as symbiosomes inside root nodule cells. To get insight into this key process, which forms the heart of the endosymbiosis, we isolated specific cells/tissues at different stages of symbiosome formation from nodules of the model legume Medicago truncatula using laser-capture microdissection. Next, we determined their associated expression profiles using Affymetrix Medicago GeneChips. Cells were collected from the nodule infection zone divided into a distal (where symbiosome formation and division occur) and proximal region (where symbiosomes are mainly differentiating), as well as infected cells from the fixation zone containing mature nitrogen fixing symbiosomes. As non-infected cells/tissue we included nodule meristem cells and uninfected cells from the fixation zone. Here, we present a comprehensive gene expression map of an indeterminate Medicago nodule and selected genes that show specific enriched expression in the different cells or tissues. Validation of the obtained expression profiles, by comparison to published gene expression profiles and experimental verification, indicates that the data can be used as digital "in situ". This digital "in situ" offers a genome-wide insight into genes specifically associated with subsequent stages of symbiosome and nodule cell development, and can serve to guide future functional studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Gene Expression Profiling*
  • Gene Expression Regulation, Plant
  • Host-Pathogen Interactions
  • In Situ Hybridization
  • Laser Capture Microdissection / methods
  • Medicago truncatula / cytology
  • Medicago truncatula / genetics*
  • Medicago truncatula / microbiology
  • Oligonucleotide Array Sequence Analysis
  • Plant Roots / cytology
  • Plant Roots / genetics*
  • Plant Roots / microbiology
  • Root Nodules, Plant / genetics*
  • Root Nodules, Plant / microbiology
  • Sinorhizobium meliloti / physiology
  • Symbiosis / genetics

Associated data

  • GEO/GSE43354

Grant support

This work was supported by the the Dutch Organization for Scientific Research (NWO grant 3184319448). Helge Küster and Jörg D. Becker acknowledge support from the Fundação para a Ciência e a Tecnologia project PTDC/AGR–GPL/70592/2006. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.