engleski

Chloroplast sensor kinase (CSK) inactivation effects photomorphogenesis in Arabidopsis thaliana

CSK is a conserved redox sensor kinase which has been shown to participate in plastoquinone redox-state dependent regulation of chloroplast reaction centre gene transcription. CSK is similarity to bacterial family of two-component signalling proteins. Unlike in typical bacterial two-component systems, CSK sensory partner is not a canonical response regulator. CSK in plants and green algae interacts with an eukaryotic serine/threonine protein kinase known as Plastid Transcription Kinase (PTK) and a chloroplast sigma factor (SIG1). We have generated isogenic Arabidiopsis plants overexpressing CSK tagged with the HA and FLAG peptides. CSK-HA-FLAG plants accumulate tagged CSK in chloroplast stroma, indicating its possible role in regulation of chloroplast gene expression. In moderate light conditions, CSK-HA-FLAG plants have long leaf petioles and resemble plants grown in low-light or light I conditions. Further, chloroplast of CSK overexpressor show subtle changes in chloroplast ultrastructure. We propose that overexpression of CSK alters photomorphogenic signals of chloroplast origin and reveals novel pathway of plant developmental regulation. References: [1] J.F. Allen, S. Santabarbara, C.A. Allen and S. Puthiyaveetil, PLOS One 6(10):e26372 (2011).

two-component signal transduction; photosynthesis; photomorphogenesis

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