Master Regulatory Transcription Factors in β-Aminobutyric Acid-Induced Resistance (BABA-IR): A Perspective on Phytohormone Biosynthesis and Signaling in Arabidopsis thaliana and Hordeum vulgare

The endogenous stress metabolite β-aminobutyric acid (BABA) primes plants for enhanced resistance against abiotic and biotic stress by activating a complex phytohormone signaling network that includes abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), and ethylene (ET). In this study, through stringent filtering, we identify 14 master regulatory transcription factors (TFs) from the DOF, AHL, and ERF families that potentially regulate the biosynthesis and signaling of these phytohormones. Transcriptional analysis of BABA-treated <i>Arabidopsis thaliana</i> and <i>Hordeum vulgare</i> suggests that DOF family TFs play a crucial role in stress response regulation in both species. BABA treatment in <i>A. thaliana</i> upregulates the TFs MNB1A and PBF and enhances the expression of the genes ICS1, EDS5, and WIN3 in the SA biosynthesis pathway, potentially boosting NPR1 and PR1 in the SA signaling pathway. Conversely, in <i>H. vulgare</i>, the BABA-induced upregulation of TF DOF5.8 may negatively regulate SA biosynthesis by downregulating ICS1, EDS5, and PR1. Additionally, in <i>A. thaliana</i>, BABA triggers the expression of TF PBF, which may result in the decreased expression of MYC2, a key gene in JA signaling. In contrast, <i>H. vulgare</i> exhibits increased expression of ERF2 TF, which could positively regulate the JA biosynthesis genes LOX and Tify9, along with the COI1 and JAZ genes involved in the JA signaling pathway. These findings offer new perspectives on the transcriptional regulation of phytohormones during plant priming.