The study identifies MtFTb1 and MtFTb2 as essential, redundant regulators of long‑day flowering in the legume Medicago truncatula, demonstrating that they are required for up‑regulating MtFTa1 under vernalised long‑day conditions. Using CRISPR/Cas9‑generated single and double mutants, the authors show that double mutants are specifically delayed in flowering under long days while retaining vernalization responsiveness, and transcriptomic analyses reveal that MtFTb1/2 activate MADS‑box genes and other flowering regulators.
Authors: Orosz, J., Lin, E. X., Torres Ascurra, Y. C., Kappes, M., Lindsay, P. L., Bashyal, S., Everett, H., Gautam, C. K., Jackson, D., Mueller, L. M.
The study identifies the pseudokinase CRN in Medicago truncatula as a regulator of inflorescence meristem branching and a negative modulator of root interactions with arbuscular mycorrhizal (AM) fungi, operating partially independently of the AM autoregulation CLE peptide MtCLE53. Transcriptomic profiling of crn mutant roots reveals disruptions in nutrient, symbiosis, and stress signaling pathways, highlighting the multifaceted role of MtCRN in plant development and environmental interactions.
The study investigated whether nitrogen‑fixing rhizobial symbiosis in Medicago truncatula primes defense against the pea aphid Acyrthosiphon pisum. Metabolite profiling (LC‑MS, GC‑MS) and qPCR revealed that symbiotic plants uniquely accumulated triterpenoid saponins and up‑regulated flavonoid‑biosynthetic genes after aphid infestation, suggesting that NFS enhances pest‑specific defenses.