Genetius

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 applied a CRISPR/Cas9 multiplex guide RNA strategy to delete entire open reading frames of four reproductive genes in Arabidopsis thaliana, achieving homozygous deletions already in the T1 generation with rates of 8.3–30%. Deletion efficiencies correlated with DeepSpCas9 prediction scores, and phenotypic analyses revealed unexpected effects of residual gene fragments on fertilization and seed 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.

The study reveals that the Arabidopsis POLARIS (PLS) peptide binds Cu(I) via two cysteine residues, forming a high‑affinity 1:2 complex that is essential for its biological function. PLS localizes to endomembranes and interacts with the transmembrane domain of the ethylene receptor ETR1 in a copper‑dependent manner, providing a mechanism that represses ethylene responses and is regulated by auxin and ethylene levels.