Interaction between programmed cell death 5 and calcineurin B-like interacting protein kinase 23 in Oryza sativa

Programmed cell death (PCD) is crucial for plants during development and stress survival. OsPDCD5, an ortholog to mammalian-programmed cell death 5, was previously cloned from rice (Oryza sativa, cv Zhenxian 97A), and its overexpression can induce PCD in transgenic rice. In the present study, immunoblotting analysis revealed that the OsPDCD5 protein was widely expressed in the tassel, leaf, leaf sheath, and different parts of the stem but not in the anther. RT-PCR analysis showed that OsPDCD5 was related to the senescence of leaf and root tissues as well as the development of stem tissues. Furthermore, OsPDCD5 was up-regulated by UV-B irradiation. Calcineurin B-like interacting protein kinase 23 (OsCIPK23), which is involved in the calcineurin B-like proteins (CLBs)/CBL-interacting protein kinases (CIPKs) signaling network, was identified as interacting with OsPDCD5 by yeast two-hybrid screening and subsequently confirmed by pull-down assay in vitro. Present findings may shed light on the investigation of the biochemical function of OsPDCD5 in rice.