| Taxol is a highly effective,low-toxic,and broad-spectrum anticancer drug.It can be used in conjunction with other drugs to have an excellent effect on cancer.But because of its extremely low content in Yew plant,the market is in short supply.So increasing the output of taxol is an important issue that needs to be solved urgently.TGA transcription factor is one of Group D members in the basic leucine zipper(b ZIP)TF family.And it is widely involved in various physiological processes such as plant stress resistance,organ development,and synthesis of secondary metabolites.This study used transcriptome data to strengthen TGA transcription factors in Taxus chinensis,and studied the role and mechanism of regulating taxol synthesis,providing genetic material and theoretical guidance to construct(or screen)taxol high-yield Taxus chinensis cell lines/plants in biotechnological means.The main results achieved in this study are as follows:(1)Using omics data,a total of 12 yew TGA transcription factors were screened through homology screening and named TcTGA1-12.Among them,only TcTGA1-10 have the ability to encode complete TGA factors.After analyzing the protein sequences of TcTGA1-10,it was found that these 10 TcTGAs are all hydrophilic proteins.They have high thermal stability and different acid-base isoelectric points.TcTGA1-10 all have protein phosphorylation sites——serine is the most,threonine is the second,and tyrosine is the least.The N-terminus of TcTGA1-10 contains nuclear localization signals and the conserved b ZIP domain,and the C-terminus contains two glutamine-rich Q1 and Q2 domains,indicating that TcTGA1-10 are typical TGA-type transcription factors.In addition,the spatial structure of TcTGA is predicted to be small and stable.Because the main forms of its secondary structure are ɑ-helix and random coil.(2)TcTGA factors and Arabidopsis TGA factors have evolutionary difference.TcTGAs can be divided into four categories,namely Class I+III,Class IV,Class V,and Class VI.Compared with At TGAs in Arabidopsis,Class VI is increased and Class II is lacked.Furthermore,phylogenetic analysis of Taxus chinensis,Arabidopsis,corn,rice,apple,grape,tomato,potato and papaya shows that there is the generation and disappearance of TGA transcription factor branches during the evolution of gymnosperms into angiosperms—the branch of TGA transcription factors of class II appears,the TGA of class I+III branches further,and the TGA of class VI of some species is lost.(3)TcTGA factors play different regulatory roles in the Skeleton synthesis and hydroxylation process of taxol,and have different regulatory effects on different taxane products.TcTGA3 negatively regulates the expression of T13 H and ERF12 genes.TcTGA7 negatively regulates the expression of T10 H,T13H and ERF12 genes.TcTGA9 negatively regulates the expression of T10 H and ERF12 genes.And the expression of T10 H and T13 H is strictly regulated by them.TcTGA10 factor has the function of positive regulation of TS,T5 H and T10 H genes.TcTGA3 and TcTGA9 mainly exert negative regulation on the synthesis of by-product 10-DAB、CEP、EDT、Taxol and ETol;TcTGA7 transcription factor mainly exerts negative regulation on the synthesis of BAT III、ETol and Taxol;while TcTGA10 transcription Factors play a positive regulatory role in the synthesis of DAT、Taxol and ETol,and negatively regulate the synthesis of EDT.(4)TcTGA3,TcTGA7,and TcTGA10 may be the direct regulators of SA signal transduction pathway regulating taxol synthesis.TcTGA3/7/10 can interact with Tc NPR1,and can interact with the cis-acting element TGACG-motif on the promoter of the target gene taxol synthesis gene. |
