DESIGNING STRATEGIES TO UNCOVER MAPK SPECIFIC FUNCTIONS IN PLANT DEVELOPMENT

VALLERO NAFARRATE, IGNACIO; MUSCHIETTI, JORGE P; WENGIER, DIEGO L.

Córdoba

Congreso; XXXII Reunión Argentina / XVI Congreso Latinoamericano de FISIOLOGÍA VEGETAL; 2018

As sessile organism, plants have acquired strategies to adjust their growth and development to environmen- tal fluctuations. This flexibility relies on mechanisms to perceive and integrate conflicting signals. In eukar- yotes, mitogen-activated protein kinases (MAPKs) are well known integrators of developmental and stress signals. Traditional genetic approaches, however, have two major obstacles when trying to uncover how MAPK signaling works: 1) redundancy obscures MAPK func- tions, so combinatorial mutants need to be generated, often resulting in pleiotropic effects; 2) some MAPKs are promiscuous and shared between different signa- ling cascades (yet signal-to-output specificity is gua- ranteed). To uncover the cellular logic behind MAPK cascades and their specificity-enforcing mechanisms, we use the development of stomata (the epidermal val- ves that regulate gas exchange), a process controlled by MAPK signaling. Here, we present a genetic screen looking for suppressors of a severe stomatal clustering phenotype caused by the artificial activation of the MAPK cascade. Among five suppressors, we found a known MAPK with novel roles in late stomatal develop- ment. This finding not only validates our screen, but also provides a context to study specificity-enforcing mechanisms. Our preliminary results suggest that ac- tivity level and subcellular localization might contribute to signaling specificity.