Control of meristem determinacy by trehalose 6-phosphate phosphatases is uncoupled from enzymatic activity

Meristem fate is regulated by trehalose 6-phosphate phosphatases (TPPs), but their mechanism of action remains mysterious. Loss of the maize TPPs RAMOSA3 and TPP4 leads to reduced meristem determinacy and more inflorescence branching. However, analysis of an allelic series revealed no correlation between enzymatic activity and branching, and a catalytically inactive version of RA3 complements the ra3 mutant. Together with their nuclear localization, these findings suggest a moonlighting function for TPPs. The mechanism of how trehalose 6-phosphate phosphatases (TPPs) regulate meristem fate remains unknown. Now, genetic and biochemical evidences support that this regulatory role is uncoupled from the enzymatic activity of TPPs.