Suppression of defense response genes in the black medic to infections under conditions of effective symbiosis with arbuscular mycorrhizal fungus Rhizophagus irregularis
Keywords:
Medicago lupulina, mycorrhizal symbiosis, arbuscular mycorrhiza, powdery mildewAbstract
The mycorrhization effect was analyzed concerning gene expression including GO:0050832 (defense reaction to fungal infection) and GO:0042742 (defence reaction to bacterial infection) groups of gene ontology under conditions of effective symbiosis in the model system “Medicago lupulina + Rhizophagus irregularis”. Massive Analysis of cDNA Ends (MACE-Seq) was applied. Under conditions of low phosphorus level, the 44 and 42 genes from defense response to the fungal and bacterial infections, respectively, were downregulated in M. lupulina leaves at the stage of 2nd leaf development and flowering. Significantly lower expression levels of genes (orthologs Medtr1g021100, Medtr1g021110) encoding powdery mildew resistance protein RPW8 were shown during mycorrhization by the fungus R. irregularis in both the vegetative and reproductive stages of development of the plant. The role of the arbuscular mycorrhiza fungus in the formation of a nonspecific reaction to pathogenic microorganisms during the development of effective symbiosis is discussed.
