IQD30 from Arabidopsis thaliana acts as a link among different cellular processes

LARA, M.V.; DRINCOVICH, M. F.; TRIASSI, A.

Congreso; LIV Reunión SAIB; 2018

Plant-specific IQ67 domain (IQD) members are part of an emerging family of calmodulin binding proteins. There are 33 IQD membersdistributed in four different classes in Arabidopsis thaliana. In this study, we made progresses in the characterization of one class IV protein of Arabidopsis, IQD30. Previously, in order to identify putative ligands of IQD30 protein, we carried out pull down assays followed by massspectrometry. Using this methodology, it was possible to detect AXR4, a protein that controls the polar localization of auxin importers, AUX1.To assess whether IQD30 gene product is involved in auxin signaling, we studied the transcriptional profile of IQD30 in Arabidopsis treatedroots with indol acetic acid (IAA). We also measured the growth of primary roots of a knockout IQD30 mutant and wild type lines underexogenous IAA treatments. qRT-PCR experiments showed that IQD30 transcript levels are significantly repressed in early post-treatment stages.On the other hand, phenotypic analysis revealed that under high concentrations of IAA, primary roots of iqd30 line exhibit lower growth thanCol-0 line. These observations suggest that the mutant line has greater sensitivity to auxin than the wild genotype indicating that IQD30 could beinvolved in the signaling of this plant hormone. At the same time, the role of IQD30 gene product in plant development was evaluated. Weobserved that iqd30 seeds show lower viability and germination speed than the wild type seeds after being exposed to normal light conditions.These results indicate that IQD30 is not an effector molecule per se but it would act as a link among different cellular processes