Expression pattern of FmNAC11 transcription factor in Fraxinus mandshurica and its function in improving cold resistance

Abstract Background: NAC domain proteins contain one of the largest families of plant specific TFs. NAC (Nam, no apical meristem; ataf1/2, Arabidopsis transcription activation factor; CUC2, cup-shaped cotyledon) is an acronym for the names of three genes originally described as containing domains, namely Nam (no apical meristem), ataf1/2 (Arabidopsis transcription activator) and CUC2 (cupular cotyledon) are plant specific transcription factors. As a regulator of gene expression, transcription factors (TF) play an important role in plant development and response to hormone signals. In order to clarify the function of Fraxinus mandshurica fmnac11 gene under biological and abiotic stress, Results: the cloned fmnac11 gene of Fraxinus mandshurica was 891bp, encoding 296 amino acids. Subcellular localization showed that fmnac11 was located in the nucleus and was indeed a transcription factor with transcriptional activation activity. Fmnac11 can respond to cold, NaCl stress, and IAA, GA, ABA hormone signal induction. The promoter length of the cloned fmnac11 gene was 2340bp. By analyzing cis acting elements, it was found that the promoter of fmnac11 gene responded to biological and abiotic stresses, participated in a variety of biological pathways, and regulated biological processes. Four transgenic lines overexpressing fmnac11 were obtained by Agrobacterium mediated transformation of WT tissue culture seedlings of Benxi tobacco. The transgenic plants grew rapidly after transplantation- Under the condition of low temperature culture at -5 ℃ for 24 hours, the wilting and yellowing degree of transgenic plants is significantly less than that of ordinary tobacco, and the transgenic tobacco overexpressing fmnac11 performs better in membrane system, osmotic system and ROS scavenging system than ordinary tobacco, indicating that fmnac11 gene has the function of improving plant cold resistance. Conclusion: the gene expression of transgenic tobacco under cold treatment shows that fmnac11 transcription factor has a regulatory relationship with growth related IAA and AUX1 genes, cold resistance related ice, DREB and CBF1, ROS clearance related cat and SOD genes, which promotes the rapid growth, cold resistance and ROS clearance ability of transgenic tobacco.