Characterization of calmodulin-binding protein IQ67-domain (IQD) in Arabidopsis thaliana

TRIASSI, AGUSTINA; DRINCOVICH, MARÍA FABIANA; LARA, MARÍA VALERIA

Mar del Plata

Congreso; LI Reunión Anual de SAIB; 2015

Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB)

Calmodulins (CaM) and CaM-like (CML) proteins are principal sensors of intracellular calcium fluctuation, whichare generated by plants in responses to abiotic and biotic stimuli. A novel class of putative plant-specific CaM andCML targets is the IQ67-Domain (IQD) family protein. Surprisingly, little is known about the biological roles ofthese proteins. We have studied the response to different abiotic stress condition of three members of Arabidopsisthaliana IQD family (IQD28, -30 and -32). Their transcripts levels were greatly induced in roots after osmotictreatment and drought, in agreement with the presence of cis-element like ABRE in their promoter regions. Thesubcellular localization of IQD28 and -30 proteins was also studied. Agrobacterium-mediated transienttransformation of N. benthamiana leaves with CFP-fusion proteins revealed a cytosolic localization for both proteins.Since a putative nuclear localization is predicted for them, transgenic Arabidopsis plants were generated by Floral dipto evaluate changes in the localization in response to osmotic stress, ABA and drought. Roots of knock out lines arebeing phenotypically characterized in response to abiotic stress. We have cloned, expressed and purified IQD28 and -30 recombinant proteins and we are currently testing their ability to bind calmodulin as well as looking for theirtargets.