Polyamine Metabolism Is Involved in the Direct Regeneration of Shoots from Arabidopsis Lateral Root Primordia

Plants can be regenerated from various explants/tissues via de novo shoot meristem formation. Most of these regeneration pathways are indirect and involve callus Besides plant hormones, the role polyamines (PAs) has been implicated in processes. Interestingly, lateral root primordia (LRPs) Arabidopsis directly converted to meristems by exogenous cytokinin application. In this system, no formation takes place. We report that level PAs, especially spermidine (Spd), increased during conversion application Spd improved its efficiency. The high endogenous could due enhanced synthesis as indicated augmented relative expression PA genes (AtADC1,2, AtSAMDC2,4, AtSPDS1,2) process. However, effect PAs on might also dependent their catabolism. POLYAMINE OXIDASE 5 (AtPAO5) was shown specifically process ectopic overexpression LRP-to-shoot This correlated with accumulation roots ROS converting LRPs. potential ways how PAO5 may influence direct organogenesis LRPs discussed.