GRAS transcription factors activated in arbuscule-containing cells of Medicago truncatula

Arbuscular mycorrhiza (AM) interactions between plants and Glomeromycota fungi primarily support phosphate aquisition by the host. To unravel the role of the AM-specific GRAS transcription factors MtGras1 and MtRam1, we performed genome-wide transcriptome profiling in RNAi-mediated MtGras1 knockdown and MtRam1 (ram1-1) mutant roots. Specifically, we used GeneChip Medicago Transcriptome Assays to identify genes differentially regulated in mycorrhizal MtGras1 knockdown or MtRam1 (ram1-1) mutant roots in comparison to control roots. Mycorrhized Medicago truncatula Gaertn ‘Jemalong’ genotype A17 plants were grown in the climate chamber, applying growth conditions reported by Hartmann et al. (2019).