Effect of the sunn mutation on systemic signalling of the plant N demand in Medicago truncatula plants inoculated for 2 or 7 days with Sinorhizobium medicae

The experiment aims to investigate the effect of the sunn mutation on systemic signaling of the plant N demand in Medicago truncatula roots inoculated with Sinorhizobium medicae MD4 at 2 and 7 days post-inoculation (dpi). We compared the TR122/sunn-2 mutant to the wild type Jemalong A17. For each plant genotype, we divided the roots systems into two parts; one of them was supplied with a nutrient solution with mineral N (10 mM NH4NO3 for N-satisfied plants, 0.5 mM for N-limited plants) whereas the non-N treated part was kept in a nutrient solution without mineral N. All roots were inoculated 48h after initiation of the N treatments. To characterize specifically the impact of systemic signaling of N demand, we collected for both genotypes the roots of the non-N treated sides of the split roots systems, and we isolated total RNA for RNAseq analysis. Root transcriptomes of N-limited and N-satisfied plants were compared in both genotypes at 2 or 7 dpi.