CRC 1208 Lecture
on Thursday, 12.05.2022,
4:30 pm- 6:00 p.m.
26.11 HS 6B
for all members of CRC 1208 and guests.

Daniёl Van Damme, University of Ghent, VIB, Belgium

"The endocytic TPLATE complex contributes to shoot apical meristem maintenance in Arabidopsis"

The evolutionarily ancient octameric TPLATE adaptor complex (TPC) is crucial for the execution of endocytosis at the plasma membrane in Arabidopsis plants. Knockout or strong knockdown of single TPC subunits causes male sterility and seedling lethality, complicating analysis of the roles of TPC during plant development. Mild knockdown or partially functional alleles of TPC subunits however only cause very mild developmental deviations. An engineered destabilized version of the TPC subunit TPLATE, termed WDXM2, in its complemented mutant background, reduced endocytic flux and showed remarkable deviations at the level of the shoot apical meristem (SAM), leading to simultaneous multiple shoot development. Reduced TPC-dependent endocytosis conferred a hypersensitivity to CLAVATA3 (CLV3) peptide signalling. This hypersensitivity correlated with the abundance of the CLV3 receptor protein kinase CLAVATA1 (CLV1) at the plasma membrane. Genetic analysis and live-cell imaging revealed that TPC-dependent internalization of CLV1 from the plasma membrane is a mechanism to dampen CLV3-mediated signalling during plant development. Furthermore, Confocal analysis combining WUSCHEL and CLV3 transcriptional markers revealed that vegetative shoot apical meristems in WDXM2-complemented plants show disordered patterning and randomized cell identity. We correlated this to TPC’s function to control callose deposition, thereby modulating symplastic movement at the SAM, which is essential for SAM homeostasis maintenance. Altogether, our results reveal that mildly perturbing TPC’s function predominantly leads to a manifestation of specific defects in SAM maintenance via a combination of altered receptor signalling and altered symplastic communication.

Host: Rüdiger Simon