Genetius

The study identifies the extended NT‑C2 domain of Plastid Movement Impaired 1 (PMI1) as the main membrane‑binding module that interacts with PI4P and PI(4,5)P2, requiring basic residues for plasma‑membrane association. Calcium binding by the NT‑C2 domain modulates its phosphoinositide preference, and cytosolic Ca2+ depletion blocks blue‑light‑induced PMI1 redistribution, indicating that both the NT‑C2 domain and adjacent intrinsically disordered regions are essential for PMI1’s role in chloroplast movement.

The study integrates multi-omics data from six Sorghum bicolor accessions under field drought to link RNA covalent modifications (RCMs) with photosynthetic performance, identifying the enzyme SbDUS2 that produces dihydrouridine (DHU) on transcripts. Loss‑of‑function dus2 mutants in Arabidopsis thaliana reveal that DHU deficiency leads to hyperstability of photosynthesis‑related mRNAs, impairing germination, development, and stress‑induced CO2 assimilation. The authors propose DHU as a post‑transcriptional mark that promotes rapid mRNA turnover during abiotic stress, enhancing plant resilience.

The study uses an optogenetic ChannelRhodopsin 2 variant (XXM2.0) to generate defined cytosolic Ca²⁺ transients in Arabidopsis root cells, revealing that these Ca²⁺ signatures suppress auxin‑induced membrane depolarization, Ca²⁺ spikes, and auxin‑responsive transcription, leading to reversible inhibition of cell division and elongation. This demonstrates that optogenetically imposed Ca²⁺ signals act as dynamic regulators of auxin sensitivity in roots.

The study demonstrates that jasmonate (JA) enhances Arabidopsis thaliana responses to extracellular ATP (eATP) by upregulating the eATP receptor P2K1 and amplifying eATP‑induced cytosolic Ca²⁺ spikes and transcriptional reprogramming in a COI1‑dependent manner, whereas salicylic acid pretreatment suppresses these responses. These findings reveal a JA‑mediated priming mechanism that potentiates eATP signaling during stress.

The study identified a suppressor mutation (sune42) in the Golgi-localized Ca2+ transporter CCX4 that alleviates the dominant‑negative root hair phenotype caused by the extensin‑less LRX1ΔE14 protein in Arabidopsis. Detailed Ca2+ imaging showed that LRX1ΔE14 disrupts tip‑focused cytoplasmic Ca2+ oscillations, a defect rescued by the sune42 mutation, highlighting the role of Golgi‑mediated Ca2+ homeostasis in root hair growth.

The authors established a live‑cell imaging platform that combines confocal microscopy of genetically encoded fluorescent protein biosensors with on‑stage illumination to monitor pH, MgATP²⁻, and NADH/NAD⁺ dynamics during dark‑light transitions in Arabidopsis mesophyll cells. They discovered that photosynthetic proton pumping triggers a stromal alkalinization wave extending to the cytosol and mitochondria, elevates MgATP²⁻ levels, and drives reduction of the NAD pool, with malate dehydrogenase mutants showing altered cytosolic redox even in darkness. This methodological advance enables high‑resolution mapping of photosynthesis‑linked energy physiology across cellular compartments.

The study compared photosynthetic performance and carbon metabolism in mature versus immature leaves of Arabidopsis thaliana accessions from different latitudes under standard and low‑temperature/high‑light conditions. Leaf‑specific measurements of Fv/Fm and CO2 assimilation revealed distinct acclimation capacities, and integration of carbohydrate and carboxylic‑acid profiles into a carbon balance model indicated that mature leaves help stabilize metabolism in younger tissue. The authors emphasize the importance of accounting for intra‑rosette heterogeneity to avoid misleading metabolic interpretations.

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.