| Summary: | A large number of hormonal biosynthetic or signaling pathways genes controlling shoot branching are widely known for their roles in regulating plant growth and development, operating in synergetic or antagonistic manner. However, their involvement in abiotic stress response mechanism remains unexplored. Initially, we performed an in silico analysis to identify potential transcription binding sites for the basic leucine zipper 62 transcription factor (bZIP62 TF) in the target branching related genes. The results revealed the presence of <i>cis-</i>regulatory elements specific to two bZIP TFs, <i>AtbZIP18</i> and <i>AtbZIP69</i>, rather than <i>AtbZIP62</i>. Interestingly, these bZIP TFs were previously proposed to be negatively regulated by the <i>AtbZIP62</i> TF under salinity in <i>Arabidopsis</i>. Therefore, we investigated the transcriptional regulation of more axillary branching (MAX, strigolactone), PIN-FORMED (PINs, auxin carriers), gibberellic acid (GA)-biosynthetic genes as well as isopentenyltransferase (IPT, cytokinin biosynthesis pathway) genes in response to drought stress in <i>Arabidopsis</i> Col-0 wild type. In addition, in the perspective of exploring the transcriptional interplay of the selected genes with the <i>AtbZIP62</i>, we measured their expression by qPCR in the <i>atbzip62</i> (lacking the <i>AtbZIP62</i> gene) background under the same conditions. Our findings revealed that the expression of <i>AtMAX2</i>, <i>AtMAX3</i>, and <i>AtMAX4 </i>was differentially regulated by drought stress between the <i>atbzip62 </i>and Col-0 wild type, but not <i>AtMAX1.</i> Similarly, the transcripts accumulation of <i>AtPIN3</i> and <i>AtPIN7 </i>(known as auxin efflux carriers), and that of the <i>AtAXR1</i> showed similar regulation patterns in <i>atbzip62</i>. However, <i>AtPIN1</i> expression was downregulated in Col-0, but no change was observed in <i>atbzip62</i>. Furthermore, <i>AtIPT5 </i>and <i>AtIPT7 </i>exhibited a differential transcripts accumulation pattern in <i>atbzip62</i> and Col-0 wild type (WT). In the same way, the expression of the GA biosynthetic genes <i>AtGA2ox1</i> and <i>AtGA20ox2, </i>and that of <i>AtRGA1</i> were differentially regulated in <i>atbzip62</i> compared to the Col-0. Meanwhile, <i>AtGA2ox1</i> showed a similar expression pattern with Col-0. Therefore, all results suggest PIN, MAX, IPT, and GA-biosynthetic genes, which are differentially regulated by <i>AtbZIP62</i> transcription factor, as emerging candidate genes that could be involved in drought stress response mechanism in <i>Arabidopsis</i>.
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