Bioinformatics Analysis And Expression Analysis Under Low Temperature Stress Of MYB Transcription Factor Family In Potato

In this study,the MYB gene family of PGSC and TAIR was used as the theoretical basis,identify and analyze the structure and function of potato MYB transcription factor family by the bioinformatics tools,and to analyze their expression patterns under cold stress.The homologous cloning and functional analysis of St4RMYB1,St2RMYB80,St3RMYB2 and AN1 genes were performed.The main results are as follows:184 potato MYB transcription factors（StMYBs）were obtained and divided into four groups:1R-MYB（67）,2R-MYB（113）,3R-MYB（3）and 4R-MYB（1）.The amino acid average of all potato MYB proteins is 519.8,and the average hydrophobicity value is negative.Gene structure analysis showed that most of R2R3-MYB proteins had a conserved splicing pattern of 3 exons and 2 introns.In the MYB domain of StMYBs protein,the R1,R2,and R3 repeat regions contain conserved tryptophan residues,but the first tryptophan residue in the R3 repeat region is usually replaced.All StMYBs genes were located on 12 chromosomes,randomly.Most of StMYBs genes exhibit tissue-specific expression.Functional predictions indicate that R2R3-MYB protein were involved in cell growth,development,secondary metabolism,and response to abiotic stress.1R-MYB protein can be divided into CCA-like,CPC-like,TRF-like,TBP-like,I-Box-binding-like and R-R type.RT-PCR was used to analyze the expression pattern of StMYBs gene in potato DM under low temperature stress.The results showed that 19 genes responded to cold stressThe St4RMYB1,St3RMYB2 and StMYB80 genes in Qingshu 9 were cloned.The CDS of St4RMYB1 was 2142 bp,which encoded 713 amino acids and had 4 MYB domains.The St2RMYB80 gene has two types,the CDS was 1110bp and 1116bp which encoded 369 and 371 amino acids,respectively.The potato St3RMYB2 gene also has two types,and the two CDS（1611bp）encoded 536 amino acids and contained 3 MYB domains.The proteins encoded by the three genes are all hydrophilic,all of which show the closest relationship with tomato,pepper,tobacco,and eggplant.The results of showed that the expression of St4RMYB1 and St3RMYB2genes was up in Qingshu 9 under 4°C,the expression of St2RMYB80 gene was down.The AN1 gene was isolated from two potato varieties which leaves were green and purple respectively,the gene sequences were the same.The CDS was 777bp and encoded 258 amino acids and contained the R2R3-MYB domain.Semi-quantitative analysis showed that the expression level in B-5 was higher than DM.The result of RT-PCR showed that GA₃,sucrose and low temperature stress increased the expression of AN1 gene.