The study demonstrates that constitutively active MLO (faNTA) can rescue the fer-4 root‑hair bursting and polarity defects, restoring tip‑focused cytosolic Ca2+ oscillations and ROS accumulation, highlighting a FERONIA‑MLO signaling module that governs Ca2+ influx and ROS production during root‑hair tip growth. Genetic analysis of mlo15-4 further confirms MLO15 as a key regulator of these Ca2+ and ROS dynamics. The findings suggest MLO proteins act downstream of FER to coordinate calcium and ROS signals essential for root‑hair integrity.

Using an Arabidopsis line expressing the CBL1‑mRuby2‑GCaMP6s calcium reporter, the study uncovered distinct calcium signatures in intact root tissues when exposed to high (5 mM) and low (0.25 mM) nitrate concentrations. Root hairs displayed prominent calcium waves and spikes, while non‑hair epidermal cells showed asynchronous or absent responses, indicating cell‑type‑specific and nitrate‑concentration‑dependent calcium signaling.

The study shows that the mechanosensitive ion channel PIEZO in Arabidopsis thaliana regulates root elongation in response to magnetic fields and blue light, with mutant plants displaying significantly shorter roots under these conditions. PIEZO expression is up‑regulated by a leaf‑derived blue‑light signal in the presence of a magnetic field, influencing calcium efflux and auxin transport via interactions with PIN3, PIN6 and PIN7, and requiring the blue‑light receptors CRY1 and CRY2. Transcriptome analysis reveals that PIEZO integrates multiple hormonal and microRNA pathways, including miR5648‑5p‑mediated negative regulation, to coordinate these environmental responses.