Strigolactone perception and deactivation by a hydrolase receptor DWARF14

Area of Science:

• Plant biology
• Molecular signaling
• Hormone perception

Background:

• Strigolactones (SLs) are crucial plant hormones regulating various developmental processes.
• The precise perception mechanism of SLs by their receptor, DWARF14 (D14), has been unclear due to D14's hydrolase activity.
• D14's ability to cleave SLs raised questions about its role in signal initiation versus termination.

Purpose of the Study:

• To elucidate the mechanism of strigolactone perception and signaling by the DWARF14 receptor.
• To determine whether intact or hydrolyzed strigolactones are responsible for initiating the active signaling state.
• To investigate the dual role of DWARF14 in both perceiving and deactivating strigolactones.

Main Methods:

• Time-course analyses of strigolactone binding and hydrolysis by Arabidopsis thaliana D14.
• Utilizing a catalytic mutant (AtD14D218A) lacking enzymatic activity to assess signaling capacity.
• Complementation assays of the atd14 mutant phenotype using the catalytic mutant.

Main Results:

• The level of uncleaved strigolactone directly correlates with the induction of the active signaling state.
• A catalytically inactive D14 mutant retains the ability to mediate strigolactone-dependent signaling.
• D14 deactivates bioactive strigolactones via hydrolysis after signal transmission.

Conclusions:

• Intact strigolactone molecules are essential for triggering the DWARF14-mediated active signaling state.
• DWARF14 functions as a dual-receptor, responsible for both initial strigolactone perception and subsequent deactivation.
• This dual function ensures precise regulation of strigolactone signaling pathways in plants.