STOP1 regulates the tolerance of Arabidopsis to low boron stress by directly activating NOD26-LIKE MAJOR INTRINSIC PROTEIN5;1 expression.

Transcriptional regulation is crucial for plants to adapt to diverse stressors; however, how plants adapt to low-boron (B) stress remains unclear. In this study, we showed that the C2H2-type transcription factor STOP1 in Arabidopsis thaliana is essential for improving plant growth under low-B conditions. Importantly, STOP1 and NIP5;1 were found to co-localise in root epidermal cells. STOP1 bound to the 5' untranslated region (UTR) of NIP5;1 to activate its expression and enhance B uptake by roots. Overexpression of STOP1 increases Arabidopsis tolerance to low-B stress by upregulating NIP5;1 transcript levels. Further genetic analyses revealed that STOP1 and NIP5;1 function together in the same pathway to confer low-B tolerance. These results highlighted the importance of the STOP1-NIP5;1 module in plant adaptation to low-B stress and better growth under low-B conditions.