Arabidopsis PIEZO Regulates Root Growth in Response to Magnetic Field and Blue Light Signaling.

The mechanosensitive ion channel PIEZO plays an important role in root growth. Magnetic fields (MF) and blue light are both known to have broad influence on plant growth as physical environmental factors; however, whether the PIEZO gene responds to MF and blue light to regulate root growth remains unclear. Here, we demonstrate that Arabidopsis PIEZO regulates root growth in response to both MF and blue light. Mutation of PIEZO led to a significantly shorter root length under MF and blue light. Moreover, PIEZO expression in root tips was up-regulated by a leaf-derived blue light signal in the presence of MF, and PIEZO affected calcium ion influx and auxin transport related to PIN-FORMED3 (PIN3), PIN6, and PIN7 under combined MF and blue light conditions. Genetic analyses revealed that the blue light receptors CRYPTOCHROME 1 (CRY1), CRY2, and PIN3 were all essential for PIEZO to perceive MF and blue light signals sent from the leaves to the roots and regulate root growth, with PIEZO acting downstream of both CRY1 and CRY2. Moreover, PIEZO influences amyloplast content and distribution in root tips under MF and blue light, though independently of the starch synthesis gene PGM1. Transcriptomic profiling and integrated gene regulatory network analysis further indicated that PIEZO coordinates multiple signaling pathways involving phytohormones (auxin, gibberellin, ethylene), Ca2+ dynamics, mechanosensors, and microRNAs, including miR5648-5p, which post-transcriptionally represses PIEZO. Our findings establish PIEZO as a central regulator that responds to MF and blue light signals to control root growth through coordinated action with CRY1/2, PIN3-mediated auxin transport, calcium flux, and amyloplast distribution. This study demonstrates that PIEZO responds to diverse signals to regulate root growth.