Study of Calmodulin-binding Protein IQ67-Domain Class IV (IQD) in Arabidopsis thaliana

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

Córdoba

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

Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB)

Calmodulins (CaM) 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 targets is the IQ67-Domain (IQD) family protein. Surprisingly, little is known about the biological roles of these proteins. We have cloned, expressed and purified three members of Arabidopsis thaliana IQD family (IQD28, -30 and -32). The recombinant proteins were used to test their ability to bind CaM in vitro and found that IQD28, -30 and -32 interact with CaM in a Ca2+-independent and -dependent manners. Also, we have studied their transcriptional response to different conditions. Their transcripts levels were repressed in leaves after salicylic acid treatment. In contrast, there were no differences of transcripts levels between control and treated roots with abscisic acid (ABA). On the other hand, transcripts levels of these genes were induced in roots after osmotic treatment. Roots of knock out lines were phenotypically characterized in response to similar stresses. Our data reveal a difference of primary root length between wild type (WT) and knock out lines (IQD32) under NaCl and ABA conditions. The length of the primary root was lower in knock out lines (IQD30) than in WT lines under control conditions. IQDs may affect root growth by binding to cytoskeletal components.