Ectopic Expression of Dendrobium catenatum DcCIPK24 Increases Drought and Salt Tolerance through ROS Scavenging in Transgenic Arabidopsis

Dendrobium catenatum is a traditional Chinese medicinal material, which has a variety of pharmacological effects such as enhancing immunity, anti-tumor and so on. However, D. catenatum has been listed as a rare and endangered plant in China due to diverse environmental stimuli including drought, salt, heat and cold. Expression analysis showed that DcCIPK24 gene displayed a tissue-specificity. DcCIPK24 was up-regulated by polyethylene glycol (PEG) 8000 and 200 mM NaCl treatments. Subcellular localization analyses revealed that DcCIPK24 is localized in the cytoplasmic. Ectopic expression of the DcCIPK24 gene in Arabidopsis showed significantly enhanced tolerance to drought and salt compared to wild-type plants. The content of reactive oxygen species (ROS) and malondialdehyde (MDA) of transgenic was significantly less than wild-type plants under salinity and drought stress. Meanwhile, the content of proline in transgenic plants was higher than that in wild-type plants under salinity and drought stresses. RNA-seq analysis indicated that DcCIPK24 functions through up-regulation of ROS-related genes. This study indicated that DcCIPK24 acts as a positive regulator in response to salt and drought stress, justify its potential application in genetic modification of D. catenatum salt and drought tolerance.