Expression and Co-expression Analyses of WRKY, MYB, bHLH and bZIP Transcription Factor Genes in Potato (Solanum tuberosum) Under Abiotic Stress Conditions: RNA-seq Data Analysis

Transcription factors regulate gene expression depending on environmental and extracellular stimuli and signals from other cells. WRKY , MYB , bHLH and bZIP transcription factors (TFs) are one of the most important TF families in plants. Therefore, WRKY , MYB , bHLH and bZIP TFs in potato ( Solanum tuberosum , St) genome under heat, salinity and drought stresses were investigated in terms of expression, co-expression and differentially expressed genes (DEGs). A total of 26,172 genes were collectively analysed in the study and four genes were identified as common DEGs, highly expressed under each abiotic stress. The salt stress was found to induce StbHLH and StMYB TFs whereas the heat stress activated StWRKY and StbZIP TFs. Moreover, the top three highly expressed genes were identified for each TF family under each stress condition. Since some of the genes were unannotated, their functional predictions including unannotated common DEGs were made based on orthologue gene comparisons in Arabidopsis . TFs involved in gene regulation along with four common DEGs were identified in co-expression analyses. As a result, 12 bHLH , 5 bZIP , 9 MYB and 14 WRKY TFs were detected in co-expression networks of the four common DEGs. Regarding DEGs, PGSC0003DMT400040149 was generally found to be involved in sulphur metabolism. PGSC0003DMT400016360 and PGSC0003DMT400007351 gene networks were found to contain more than 400 overlapping genes, suggesting that they may have roles in similar pathways in response to abiotic stress conditions in potato. Lastly, we found that MYB - bHLH cross talking may occur in response to abiotic stresses in potato. The findings are particularly important to understand roles of TFs under the mentioned stresses in potato.