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

TRIASSI, A; MARIA FABIANA DRINCOVICH; LARA, MARÍA VALERIA

Congreso; LI Reunión de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Calmodulins (CaM) and CaM-like (CML) proteins are principal sensors of intracellular calcium fluctuation, which are generated by plants in responses to abiotic and biotic stimuli. A novel class of putative plant-specific CaM and CML targets is the IQ67-Domain (IQD) family protein. Surprisingly, little is known about the biological roles of these proteins. We have studied the response to different abiotic stress condition of three members of Arabidopsis thaliana IQD family (IQD28, -30 and -32). Their transcripts levels were greatly induced in roots after osmotic treatment and drought, in agreement with the presence of cis-element like ABRE in their promoter regions. The subcellular localization of IQD28 and -30 proteins was also studied. Agrobacterium-mediated transient transformation 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 dip to evaluate changes in the localization in response to osmotic stress, ABA and drought. Roots of knock out lines are being 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 their targets.