Analysis On Stress Resistance Of SlNAC8 Transgenic Arabidopsis And Its Mechanism

NAM/ATAF/CUC(NAC)transcription factors play an important role in resisting abiotic stress in plants.In this study,a novel NAC gene,designated SlNAC8,was characterized from Suaeda liaotungensis K.SlNAC8 protein is localized in the nucleus,and yeast one-hybrid screening showed that it contains an activation domain in its C-terminus and functions as a transcriptional activator.Gene expression analysis revealed that it is induced by drought and salt stress and low temperature.In this study,SlNAC8 transfected Arabidopsis,wild-type,and transfected Arabidopsis with empty vector as materials were detected on the morphological,physiological indexes of each types of Arabidopsis under different stress conditions.The results of morphological show that Arabidopsis plants overexpressing SlNAC8 shows significant advantages in seed germination under drought,salt and low temperature stress.Arabidopsis plants overexpressing SlNAC8 shows significant advantages in root growth,shoot growth,plant height,pod number and survival rate compared with controls under drought and salt stress.Under drought,salt and low temperature stress,the stomatal opening rate in leaves of Arabidopsis plants overexpressing SlNAC8 is significantly higher than that of wild-type.The results of physiological show that transgenic plants had a significantly higher proline concentration,antioxidant enzyme activity(superoxide dismutase,peroxidase,and catalase),and level of chlorophyll fluorescence than wild-type,and a significantly lower malondialdehyde concentration and electrolyte leakage under drought and salt stress.In addition,the relative expression of related stress-responsive genes are detected by qRT-PCR.The overexpression of SlNAC8 in transgenic plants also enhanced the expression of stress-responsive genes such as AtRD20,AtGSTF6,AtCOR47,AtRD29 A,AtRD29B,and AtNYC1.Among them,AtRD20 is related to stomatal switching,AtGSTF6 is related to the synthesis of glutathione transferase,and AtNYC1 is related to photosynthetic efficiency.In this study,SlNAC8 enhanced the plant growth ability and physiological activity by regulating the expression of downstream genes,it reveals that SlNAC8 plays an important regulatory role in plant response to stress and provides a new theory for stress resistance research.