Endogenous NO modulates spatial distribution of PIN2 during gravitropism in Arabidopsis

SILVANA LORENA, COLMAN; RAMIRO, PARIS; MARÍA MAGDALENA, VAZQUEZ; MARISA, OTEGUI; MARÍA C, TERRILE; CLAUDIA A, CASALONGUÉ

Córdoba

Congreso; LII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

Nitric oxide (NO) is an endogenous signaling moleculeimplicated in several key auxin-mediateddevelopmentalprocesses includinggravitropism. The asymmetry in the auxindistribution during the gravitropic response is established andmaintained by the spatiotemporalregulationof the PIN2 auxintransporter facilitator abundance. Our results showed anasymmetric NO accumulation inepidermic cells of gravi-stimulatedArabidopsis roots. Dynamic changes of NOdistribution co-localizedwith the asymmetric auxinabundancein the upper and lower sides of the root tip. The regulation ofPIN2 distribution by NO during the gravitropic responsewasinvestigated in PIN2-GFPtransgenic plants subjected to NOdonor (NO-Cys)and the scavenger (cPTIO) treatments.Endogenous NOwas critical in the asymmetric abundance ofPIN2 during gravitropism. Preliminary results indicated thatcompared with wild type, thedouble mutant nia1/nia2 showed areduced root bending after 135° root reorientation. Only 44% of mutant plants showed the expectedorientation towards gravity.We are carrying out genomic and physiological researches to investigate the role played by the coordinatedaction of auxin and NO during gravitropism. Supported by CONICET, ANPCyT,UNMdP.