Overexpression of DnWRKY29 in tobacco impaired plants tolerance to salt and drought stresses

One novel transcription factor gene DnWRKY29 was isolated from Dendrobium officinale, and its functions were identified by its overexpression in tobacco. Compared to the wild type (WT), the DnWRKY29 transgenic tobacco seeds and seedlings showed more sensitivity to salt and drought stresses. The seed germination rate, seedling root length, and fresh weight of transgenic tobacco were lower than in WT. The activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) in transgenic tobacco were decreased, and the content of malondialdehyde (MDA) in transgenic tobacco was increased. Moreover, the expression of DnWRKY29 was up-regulated in Dendrobium seedlings under salt and drought stresses, which was consistent with the function identified by its overexpression in tobacco, indicating that the up-regulation or overexpression of DnWRKY29 impaired plant tolerance to salt and drought stresses. These results provided a new insight to the low tolerance of Dendrobium seedlings to environmental change.