Altered expression of a CCT domain-containing protein leads to deregulation of hydrogen peroxide levels in Arabidopsis thaliana plants

OSELLA; V; VALLE EM; ZANOR MI

Congreso; Reunión Anual SAIB 2013; 2013

CCT domain-containing proteins are found in a wide range of flowering plants but not in mammals or yeast. They are considered to function as transcriptional regulators implicated in diverse processes such as photoperiodic flowering, regulation of circadian rhythms, light signalling and gene expression in response to sugars. Here we report the identification of a CCT domain-containing protein (UKCCT) which is downregulated upon treatment of Arabidopsis seedlings with the herbicide Methyl Viologen in light. In this work we analyzed sub cellular and tissue specific expression using transgenic plants. Arabidopsis plants expressing the UKCCT-GFP fusion protein showed nuclei localization indicating that UKCCT function might be related to regulatory processes. Using promoter-GUS reporter fusions we observed high expression of UKCCT in shoots, especially in cotyledons and leaves but not in stem and roots. Interestingly, Arabidopsis plants over-expressing UKCCT show a deregulation of H2O2 levels, chlorotic and hyponastic leaves resembling the phenotype observed in cat2 mutants. On the other side, ukcct mutant lines showed a better photosynthesis performance and higher seed set. Our working hypothesis is that the function of this protein is related to the regulation of hydrogen peroxide levels and to senescence onset.