Medicago truncatula Transcriptome or Gene expression. Medicago truncatula

Legumes interact with soil microbes, leading to the development of nitrogen-fixing root nodules and arbuscular mycorrhizal (AM) roots. While nodule initiation by diffusible lipochitooligosaccharide (LCO) Nod-factors of bacterial origin (Nod-LCOs) is well characterized, diffusible AM fungal signals were only recently identified as sulphated and non-sulphated LCOs (sMyc-LCOs and nsMyc-LCOs). Applying Myc-LCOs in parallel to Nod-LCOs, we used GeneChips to detail the global programme of gene expression in response to the external application of symbiotic LCOs. Overall design: To harvest tissues for transcriptome profiling, three biological replicates consisting of 20 plantlets per treatment were selected. After 6 h of incubation in the climate chamber, 10 plantlets per batch were removed from the treatment (Myc-LCOs or Nod-LCOs) or control solutions and harvested, while the other 10 remained in the respective solutions for a total of 24 h. During harvest, one mm of the root tip of each plantlet was removed and discarded. The remaining 2 to 2.5 cm of the distal root region were cut off and directly frozen in liquid nitrogen.