| In recent years,with the continuous development of molecular biology and molecular genetics,transcription factors have gradually become an important research content in this field.MYB transcription factor(v-myb avian myeloblastosis viral oncogene homolog),as one of the largest families of transcription factors in plants,has attracted the attention of researchers.It is widely distributed in plants and plays important biological functions,including plant growth and development,secondary metabolic regulation,and stress response.However,the current research on the regulation of ginsenoside synthesis by MYB transcription factors has not been repaid.This experiment is based on the Jilin ginseng 248,993 unigenes transcriptome database constructed in the laboratory,Bioinformatics method was used to mine the ginseng MYB transcription factor family and screened for PgMYB38 closely related to ginsenoside synthesis,gene function analysis by low temperature stress.Genetic transformation using Arabidopsis thaliana as a receptor material.The main experimental results obtained are as follows:1.A total of 215 PgMYBs were screened out,of which 94 had complete open reading frames and conserved domains.2.GO annotation and enrichment analysis of PgMYBs showed that MYB transcriptional factor is widely involved in the growth and development of ginseng.Among all the functions annotated at Level 2,the combination of functional genes has the highest proportion of genes,which is consistent with transcription factors.The characteristics were all significantly enriched compared to the control.3.The 94 PgMYBs were combined to retain the longest sequence under the same gene ID,and a total of 31 PgMYBs were obtained.The phylogenetic tree was constructed with Arabidopsis thaliana,Solanum lycopersicum,and Solanum tuberosum L.,the results showed that PgMYBs were divided into 4 subtypes and contained different sequences,genes from the same subfamily get together,indicating that the MYB transcription factor is relatively conservative during evolution.4.Perform network analysis on PgMYBs.PgMYB38 and PgMYB61-7 have significant interactions with key enzyme genes in the synthesis of ginsenosides and are synergistically expressed.5.PgMYB38 was stably expressed in 42 farm cultivars,14 tissues and organs and 4 different ginseng roots..6.Low-temperature treatment of ginseng hairy roots for gene expression analysis,PgMYB38 was significantly up-regulated at different times,and the key enzyme genes of ginsenoside synthesis,HMGR,SS and SE,were significantly down-regulated.7.The PgMYB38 gene was successfully cloned and a super-expression vector was constructed.Agrobacterium-mediated transformation of Arabidopsis thaliana to obtain Arabidopsis thaliana T2 positive plants8.Gene expression analysis of Arabidopsis thaliana T2 positive plants showed that the key enzyme genes regulating 2,3-oxidized squalene synthesis were significantly down-regulated. |
