Genetius

Using a forward genetic screen of 284 Arabidopsis thaliana accessions, the study identified extensive natural variation in root endodermal suberin and pinpointed the previously unknown gene SUBER GENE1 (SBG1) as a key regulator. GWAS and protein interaction analyses revealed that SBG1 controls suberin deposition by binding type‑one protein phosphatases (TOPPs), with disruption of this interaction or TOPP loss‑of‑function altering suberin levels, linking the pathway to ABA signaling.

The study investigates how the timing of the vegetative phase change (VPC) in Arabidopsis thaliana influences drought adaptation, revealing strong genotype-by-environment interactions that create stage-specific fitness tradeoffs. Genotypes from warmer, drier Iberian climates transition earlier, and genome-wide association mapping identifies loci linked to VPC timing and drought response, with several candidates validated using T‑DNA insertion lines.

The study shows that inoculation with the non‑diazotrophic bacterium Enterobacter sp. SA187 significantly improves Arabidopsis thaliana growth under low nitrate conditions by increasing fresh weight, primary root length, and lateral root density, while enhancing nitrate accumulation and reducing shoot C:N ratios. Transcriptomic and mutant analyses reveal that these benefits depend on ethylene signaling and the activity of high‑affinity nitrate transporters NRT2.5 and NRT2.6, indicating an ethylene‑mediated, HATS‑dependent reprogramming of nitrogen uptake.

The study reveals that Arabidopsis ethylene receptors ETR1 and ERS1 function as Ca²⁺-permeable channels, with ETR1 specifically mediating ethylene‑induced cytosolic Ca²⁺ spikes that influence hypocotyl elongation. Homologous receptors from diverse land plants and algae also show Ca²⁺ permeability, and ethylene further enhances this activity, indicating a conserved regulatory role across the green lineage.

The study uncovers a reciprocal regulatory loop between type one protein phosphatases (TOPPs) and EIN2 in ethylene signaling, showing that ethylene induces TOPPs expression and that TOPPs dephosphorylate EIN2 at S655 to stabilize it and promote nuclear accumulation. TOPPs act upstream of EIN2, while EIN3/EIL1 transcriptionally activates TOPPs, linking dephosphorylation to enhanced ethylene responses and improved salt tolerance.

A genome-wide association study of 166 Iberian Arabidopsis accessions identified loci, including ABA3 and GA2ox2, that modulate the inhibitory effect of the auxin precursor indole-3-acetamide (IAM) on primary root elongation. Integrating sequence analysis, transcriptomics, 3D protein modeling, and mutant physiology revealed that IAM promotes ABA biosynthesis and signaling, uncovering a novel node of hormone crosstalk.

The study profiled root transcriptomes of Arabidopsis wild type and etr1 gain-of-function (etr1-3) and loss-of-function (etr1-7) mutants under ethylene or ACC treatment, identifying 4,522 ethylene‑responsive transcripts, including 553 that depend on ETR1 activity. ETR1‑dependent genes encompassed ethylene biosynthesis enzymes (ACO2, ACO3) and transcription factors, whose expression was further examined in an ein3eil1 background, revealing that both ETR1 and EIN3/EIL1 pathways regulate parts of the network controlling root hair proliferation and lateral root formation.

The authors engineered a novel ethylene‑responsive promoter (EBSn) containing ten divergent natural EIN3‑binding sites and demonstrated that it provides higher sensitivity and broader tissue expression than existing reporters in Arabidopsis thaliana. The EBSn promoter successfully monitored endogenous ethylene levels and also functioned in tomato, suggesting utility for studying ethylene‑regulated processes such as fruit ripening.

The study identifies HISTONE DEACETYLASE COMPLEX 1 (HDC1) as a positive regulator of sepal size during maturation in Arabidopsis thaliana, showing that hdc1 mutants exhibit prolonged elongation due to delayed maturation. Integrated transcriptomic and proteomic analyses, together with genetic and chemical experiments, reveal that HDC1 promotes ethylene production, which in turn triggers ROS accumulation to terminate sepal growth. These findings elucidate a coordinated ethylene‑ROS signaling mechanism controlling organ size during plant development.

The study shows that soil compaction induces ethylene production, which upregulates Auxin Response Factor1 in the root cortex and represses cellulose synthase genes, leading to altered cell wall thickness and mechanics that cause radial expansion of cortical cells. This ethylene‑mediated modulation of cell wall strength creates a stiff epidermis‑soft cortex architecture, linking hormonal signaling to root mechanical adaptation in compacted soils.