Reactive oxygen species signalling is involved in alkamide-induced altered root development.

Alkamides are alpha unsaturated N-acylamides structurally related to N-acyl ethanolamides (NAEs) and N-acyl-L-homoserine lactones (AHLs). Studies have shown that alkamides induce prominent changes in root architecture, a significant metabolic readjustment, and transcriptional reprogramming. Some alkamide responses have been associated with redox signalling; however, this involvement and ROS sources have not been fully described. We utilized a genetic approach to address ROS signalling in alkamide-induced processes and found that in Arabidopsis, treatment with the alkamide affinin (50{micro}M) increased the in-situ accumulation of H2O2 in lateral root emergence sites and reduced H2O2 accumulation in primary root meristems implying that altered root growth was dependent on endogenous H2O2. Results show that ROS sourced from PRX34, RBOHC and RBOHD were involved in promotion of lateral root emergence by alkamides. RBOHC was required for affinin-induced enhanced root hair expansion. Furthermore, affinin-induced changes in lateral root emergence, but not root hair length, were dependent on a change in extracellular pH. Finally, reverse genetic experiments suggest heterotrimeric G-proteins were involved in plant response to alkamides; nevertheless, further studies with additional higher order G-protein mutants will be required to resolve this question. These results support that alkamides recruit specific ROS signaling programs to mediate alterations in root architecture. HighlightReactive oxygen species (ROS) are involved in alkamide-induced altered root development. Heterotrimeric G-protein complex, extracellular acidification, and ROS sourced from peroxidases and NADPH-oxidases are involved in these processes.