As shown by a team around Tokyo University of Agriculture (Professor Yoichi Sakata), Group A protein phosphatases type 2C (PP2C) are negative regulators of abscisic acid signalling. Deletion of group A PP2C was sufficient to ensure P. patens survival to full desiccation, without ABA treatment

Kenji KOMATSU et al., Nature Communications July 31, 2013, doi:10.1038/ncomms3219