Overexpression Of Kandelia Candel C2H2Zinc-finger Protein Gene KcZFP Enhanced Salinity Tolerance In Tobacco Plants

Transcriptional regulation is one of the important factors in plant adaption to abiotic stress. In stress signaling pathway, transcription factors regulate downstream genes and play a critical role in the plant acclimation to adverse environments. Among transcription factors involved in abiotic stress response, zinc finger proteins represent a large protein family which displays diverse roles in various biological processes. In this study. the function of a KcZFP gene, encoding a Cys2/His2-type zinc-finger protein of Kandelia Candel, was investigated in tobacco plants under salt treatment.The gene construct of the KcZFP under the control of constitutive promoter pK-WG2D was transformed into tobacco. KcZFP-overexpressed tobacco plants were obtained by agrobacterium-mediated gene transformation. Twenty-five KcZFP transformed kanamycin resistant tobacco lines were analysed by PCR and sixteen of the twenty-five lines were KcZFP-positive indicating the existence of transgene in the genome. Among them eleven transgenic lines showed over expression of KcZFP based on qRT-PCR. The results showed that the transcript abundance of KcZFP was markedly elevated in transgenic plants. Salinity tolerance of KcZFP-transgenic plants was tested under200mmol/L NaCl. KcZFP-overexpressed tobacco plants exhibited an obviously higher salt tolerance than that of the wild type. The proline concentration in leaves of transgenic plants was markedly higher than that in wild-type under200mmol/L NaCl treatment. Moreover, the MDA content of.KcZFP-overexpressed tobacco was much lower than that of the wild-type tobacco. Noteworthy, net photosynthetic rate in KcZFP-overexpressed tobacco was less affected by salinity stress, as compared to the wild type. This result suggested that the elevated proline should exert a protective effect on the photosynthetic system. In terms of chang trend, no significant difference on K+/Na+was observed between KcZFP-overexpressed tobacco plants and wild type plant. Therefore, our results suggest that as transcription regulator KcZFP contribute to osmotic regulation in response to NaCl stress.