Dissertation: Stress and developmental responses in Arabidopsis thaliana: Regulation through the transcription factor-interacting protein RCD1

12.03.2010

In her doctoral thesis in the field of biosciences, Pinja Jaspers (University of Helsinki) investigated the molecular biology of plants. Dissertation concentrates on an important RCD1 protein and its closest homolog SRO1. Resources of CSC — IT center for science were utilized in the studies.

Plants constantly face adverse environmental conditions, such as drought or extreme temperatures that threaten their survival. They demonstrate astonishing metabolic flexibility in overcoming these challenges and one of the key responses to stresses is changes in gene expression leading to alterations in cellular functions. This is brought about by an intricate network of transcription factors and associated regulatory proteins. Protein-protein interactions and post-translational modifications are important steps in this control system along with carefully regulated degradation of signaling proteins.

Double Mutant Plant © Pinja Jaspers

Dissertation concentrates on the RCD1 protein, which is an important regulator of abiotic stress-related and developmental responses in Arabidopsis thaliana. Plants lacking this protein function display pleiotropic phenotypes including sensitivity to apoplastic reactive oxygen species (ROS) and salt, ultraviolet B (UV-B) and paraquat tolerance, early flowering and senescence. Additionally, the mutant plants overproduce nitric oxide, have alterations in their responses to several plant hormones and perturbations in gene expression profiles.

In conclusion, RCD1 is a key point of signal integration that links ROS-mediated cues to transcriptional regulation by yet unidentified means, which are likely to include post-translational mechanisms. The C-terminus of RCD1 contains a novel domain called RST. It is present in RCD1-like proteins throughout the plant kingdom and is able to mediate physical interactions with multiple transcription factors. The identification of RCD1-interacting transcription factors, most of whose functions are still unknown, opens new avenues for studies on plant stress as well as developmental responses.

More information
Pinja Jaspers,
+358 9 191 594 39, pinja.jaspers@helsinki.fi

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