Overlaps in the transcriptional profiles of Medicago truncatula roots inoculated with two different Glomus fungi provide insights into the genetic program activated during arbuscular mycorrhiza.
Arbuscular mycorrhiza (AM) is a widespread symbiotic association between plants and fungal microsymbionts that supports plant development under nutrient-limiting and various stress conditions. In this study, we focused on the overlapping genetic program activated by two commonly studied microsymbionts in addition to identifying AM-related genes. We thus applied 16,086 probe microarrays to profile the transcriptome of the model legume Medicago truncatula during interactions with Glomus mosseae and Glomus intraradices and specified a total of 201 plant genes as significantly coinduced at least 2-fold, with more than 160 being reported as AM induced for the first time. Several hundred genes were additionally up-regulated during a sole interaction, indicating that the plant genetic program activated in AM to some extent depends on the colonizing microsymbiont. Genes induced during both interactions specified AM-related nitrate, ion, and sugar transporters, enzymes involved in secondary metabolism, proteases, and Kunitz-type protease inhibitors. Furthermore, coinduced genes encoded receptor kinases and other components of signal transduction pathways as well as AM-induced transcriptional regulators, thus reflecting changes in signaling. By the use of reporter gene expression, we demonstrated that one member of the AM-induced gene family encoding blue copper binding proteins (MtBcp1) was both specifically and strongly up-regulated in arbuscule-containing regions of mycorrhizal roots. A comparison of the AM expression profiles to those of nitrogen-fixing root nodules suggested only a limited overlap between the genetic programs orchestrating root endosymbioses.
Hohnjec
Natalija
N
Lehrstuhl für Genetik, Fakultät für Biologie, Universität Bielefeld, D-33615 Bielefeld, Germany.
Vieweg
Martin F
MF
Pühler
Alfred
A
Becker
Anke
A
Küster
Helge
H
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D020869:Gene Expression Profiling; D017343:Genes, Plant; D046913:Medicago truncatula / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology*; D008969:Molecular Sequence Data; D038821:Mycorrhizae / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010937:Plant Growth Regulators / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology; D015398:Signal Transduction; D013559:Symbiosis / Q000235:genetics; D014158:Transcription, Genetic
D002352:Carrier Proteins; D010937:Plant Growth Regulators; D010940:Plant Proteins