Effect of ethylene on bisphenol A-inhibited primary root elongation in <i>Arabidopsis thaliana</i>

Bisphenol A (BPA), a widespread industrial chemical, significantly inhibits root elongation, reducing it by 2%, 32%, and 64% at concentrations of 10, 20, 30, and 40 µM, respectively. This study delves into the interplay between ethylene and auxin in mediating BPA-induced primary root growth inhibition in <i>Arabidopsis thaliana</i>. Furthermore, ethylene modulates BPA sensitivity, as evidenced by reduced inhibition in ethylene-insensitive mutants (etr1-1, etr1-3, ein2-1) and heightened sensitivity in ethylene-overproducing lines (eto1-1, ctr1-1). Ethylene biosynthesis inhibitors (AVG, CoCl2) significantly decreased BPA-induced root inhibition. Treated plants showed increased expression of ethylene biosynthetic genes (ACS2, ACS6, ACS8, ACO1, ACO2). Auxin involvement was evident as aux1-7 mutants showed reduced sensitivity, and NPA (an auxin transport inhibitor) improved root growth. BPA and ACC treatments elevated DR5 and EBS activity, indicating enhanced ethylene and auxin signaling. AVG or NPA effects on DR5 activity under BPA stress revealed that ethylene modulates auxin accumulation and distribution. The study suggests that ethylene regulates BPA-mediated root inhibition by influencing AUX1 expression and auxin distribution, offering new insights into the interaction between ethylene, auxin, and BPA in plant growth.