Genetius

The study reveals that reactive oxygen species (ROS) have distinct temporal roles in Arabidopsis thaliana stigma papillae development, with superoxide promoting early growth and hydrogen peroxide marking mature, pollen‑receptive papillae. Pharmacological reduction of superoxide or transgenic over‑expression of superoxide dismutase under an early stigma promoter impairs papillae growth, highlighting ROS homeostasis as essential for proper papillae differentiation and successful pollination.

Loss‑of‑function mutations in the drought‑induced genes GASA3 and AFP1 confer enhanced drought tolerance in Arabidopsis thaliana, primarily through smaller stomatal apertures and increased ABA accumulation via hydrolysis of ABA‑GE. Constitutive overexpression of these genes heightens drought sensitivity, indicating that the AFP1/GASA3 module negatively regulates stomatal closure and ABA signaling.

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 demonstrates that dihydroxy B‑ring flavonoids modulate the amplitude of the core circadian clock gene reporter TOC1:LUC in Arabidopsis by affecting cellular H2O2 levels, rather than auxin transport. Reducing reactive oxygen species restored normal TOC1:LUC amplitude in flavonoid‑deficient seedlings, and altered chloroplast Ca2+ levels suggest a retrograde signaling component.

The study identifies the scaffolding protein RACK1A as a cytoplasmic interaction partner of the antioxidant enzyme FSD1, revealing that RACK1A recruits FSD1 to cycloheximide-sensitive condensates that colocalize with stress granules during salt stress. Functional analyses show that this RACK1A‑FSD1 module modulates ROS levels, influences root hair tip growth, and determines salt‑stress resilience in Arabidopsis.

The study reveals that hydrogen sulfide (H₂S) and the cysteine desulfhydrase DES1 are essential for stomatal immunity, mediating flg22‑ and bacterial‑induced stomatal closure and influencing reactive oxygen species (ROS) dynamics. Loss‑of‑function des1 mutants show altered susceptibility to Pseudomonas syringae and reduced apoplastic and cytosolic H₂O₂ accumulation, while H₂S can induce ROS production independently of RBOHD.