Minimal auxin sensing levels in vegetative moss stem cells revealed by a ratiometric reporter ($) (New Phytologist)

Auxin plays multiple developmental roles from embryogenesis to seed development. To understand the mechanism of auxin response in plants, researchers utilize the early-diverging land plant models, Physcomitrella patens and Marchantia polymorpha. In this paper, Thelander et al., have identified a specific reporter of auxin levels for P.patens, PpR2D2 (Ratiometric version of DII-nVENUS to mDII-nTdTOMATO signal). This reporter developed for P. patens similar to Arabidopsis serves as a proxy for detecting TIR/AFB (TRANSPORT INHIBITOR RESISTANT1/AUXIN F-BOX) dependent auxin sensing system. PpR2D2 can detect very minimal levels of auxin during the early development of the moss, P.patens which enable researchers to understand the core auxin mechanism in development. The authors have validated the expression of this marker to the other auxin output marker DR5 and have demonstrated the significance of this marker in different growth stages of P.patens and also in response to exogenous auxin. Thus an added tool to dissecting auxin role in plant development has been shown. Summary by Suresh Damodaran. DOI :