Genetius

The study characterizes the chloroplast‑localized protein AT4G33780 in Arabidopsis thaliana using CRISPR/Cas9 knockout and overexpression lines, revealing tissue‑specific expression and context‑dependent effects on seed germination, seedling growth, vegetative development, and root responses to nickel stress. Integrated transcriptomic (RNA‑seq) and untargeted metabolomic analyses show extensive transcriptional reprogramming—especially of cell‑wall genes—and altered central energy metabolism, indicating AT4G33780 coordinates metabolic state with developmental regulation rather than controlling single pathways.

The study examined the roles of AtKUP2, AtKUP6, AtKUP8, and GORK potassium transport proteins in guard cell function by performing gas-exchange measurements on mature Arabidopsis leaves. Loss of KUP2/6/8 reduced stomatal conductance, whereas a GORK loss‑of‑function mutant showed increased conductance, yet the magnitude of light‑ and ABA‑induced transpiration changes remained similar across genotypes, suggesting a limited dynamic range for rapid stomatal movements that relies on small ionic osmolytes.

The study shows that Arabidopsis root tips adapt to hypoxia by increasing H3K4me3 levels, linked to the inhibition of group 7 demethylases (KDM7s). Genetic loss of KDM7s mimics hypoxic conditions, activating genes that sustain meristem survival, suggesting KDM7s act as root‑specific oxygen sensors that prime epigenetic tolerance mechanisms.

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.

The study demonstrates that the chromatin remodeler DDM1 is essential for biomass heterosis in Arabidopsis thaliana hybrids, as loss of DDM1 function leads to reduced rosette growth and extensive genotype‑specific transcriptomic and DNA methylation changes. Whole‑genome bisulfite sequencing revealed widespread hypomethylation in ddm1 mutants, while salicylic acid levels were found unrelated to heterosis, indicating that epigenetic divergence, rather than SA signaling, underpins hybrid vigor.

The study reveals that the methyl‑CpG‑binding domain protein MBD8 interacts with the histone demethylase LDL2 to facilitate removal of H3K4me1 and transcriptional repression downstream of H3K9me2 in Arabidopsis. MBD8 binds GC‑poor DNA independently of cytosine methylation and stabilizes LDL2 protein levels, indicating a broader role for MBD proteins beyond methyl‑DNA recognition.

The study applied a progressive, sublethal drought treatment to Arabidopsis thaliana, collecting time‑resolved phenotypic and transcriptomic data. Machine‑learning analysis revealed distinct drought stages driven by multiple overlapping transcriptional programs that intersect with plant aging, and identified high‑explanatory‑power transcripts as biomarkers rather than causal agents.

The study shows that inoculating Arabidopsis thaliana with the plant‑growth‑promoting bacterium Enterobacter sp. SA187 markedly boosts root and shoot biomass under elevated CO₂, accompanied by altered nitrogen and carbon content and reshaped phytohormone signaling. Transcriptomic and metabolomic analyses reveal activation of salicylic acid, jasmonic acid, and ethylene pathways and enhanced primary metabolism, while the ethylene‑insensitive ein2‑1 mutant demonstrates that the growth benefits are ethylene‑dependent.