Genetius

The study generated ten phosphomimetic variants of the Arabidopsis G protein subunit GPA1 to examine how phosphorylation influences its biochemical activity and developmental functions. In vitro assays showed that phosphovariants at S49 and S52 reduce GTP/GDP binding, while in vivo analyses revealed that morphological phenotypes are independent of nucleotide binding status and that different phosphomimetic sites confer distinct signaling outcomes, supporting a multi‑state model for GPA1 signaling.

The study combines time‑resolved redox imaging with gas‑exchange measurements to show that darkness‑induced inactivation of carbon assimilation in plants depends on an oxygen‑dependent oxidative burst linked to PSI activity. Mutants lacking PGR5/PGRL1 display reduced oxidative bursts and less Calvin‑Benson cycle inhibition, indicating that the water‑water cycle supplies the transient oxidizing equivalents required for enzyme inactivation during the light‑to‑dark transition.

The study reveals that the interaction between spliceosomal proteins STA1 and DOT2 regulates nuclear speckle formation, pre‑mRNA splicing efficiency, and heat stress tolerance in Arabidopsis. A missense mutation in DOT2 restores this interaction in a sta1‑1 mutant, linking interaction strength to nuclear speckle organization and splicing robustness, especially under heat stress.

The study investigates how systemic iron signaling integrates reductive iron uptake and coumarin‑mediated iron mobilization in Arabidopsis thaliana under iron‑sufficient, alkaline, and iron‑deficient conditions. Mutants lacking the OPT3 systemic signaling component (opt3‑2) maintain higher chlorophyll, persistent ferric chelate reductase activity, and enhanced coumarin secretion, whereas the coumarin‑deficient mutant (f6h1‑1) shows severe chlorosis with compensatory reductase induction; co‑cultivation shows opt3‑2‑derived coumarins can partially rescue f6h1‑1. These results identify systemic signaling as a key regulator of iron homeostasis.

The study generated Botrytis cinerea mutants expressing the salicylate hydroxylase NahG, which degrades salicylic acid, and found that these mutants grow better on SA and exhibit increased virulence on Arabidopsis thaliana and Phaseolus vulgaris. The enhanced pathogenicity depends on the host’s SA biosynthesis, as no effect is seen on SA‑deficient Arabidopsis sid2‑2, indicating that fungal SA degradation is a virulence strategy. Transcriptomic analysis shows that B. cinerea possesses four SH‑like genes with distinct expression during infection across hosts.

The study demonstrates that the microtubule-associated protein MAP70-2 integrates mechanical and biochemical signals to direct division plane orientation during early lateral root primordium formation in Arabidopsis thaliana. MAP70-2 localizes dynamically to cell corners and the cortical division zone, and its loss results in misoriented divisions and defective root morphogenesis, highlighting its role in overcoming mechanical constraints during organogenesis.

Using ribosome profiling and RNA‑seq, the study reveals that Arabidopsis thaliana seeds maintain a poised translational state with ribosomes pre‑positioned on stored mRNAs, and that release from dormancy triggers gene‑specific changes in translational efficiency largely independent of transcript levels. Translational control, especially via ribosome pausing and upstream open reading frame (uORF)‑mediated repression, emerges as a key mechanism governing the dormancy‑to‑germination transition.

The study reveals that the Kelch phosphatase BSU1, previously known as a brassinosteroid signaling component, functions as a PP1-like serine/threonine phosphatase whose activity is regulated by CDK-mediated phosphorylation of its C‑terminal tail, linking hormone signaling to cell‑cycle control. Loss‑of‑function and phospho‑mutant analyses in Arabidopsis and Marchantia demonstrate that BSU1 and its homologs modulate growth, stomatal patterning, fertility, and cell differentiation through this conserved regulatory mechanism.

The study investigates the chloroplast‑localized protein AT4G33780 in Arabidopsis thaliana using CRISPR knockout and overexpression lines, revealing dosage‑ and context‑dependent effects on seed germination, seedling growth, vegetative development, and root responses to nickel stress. Integrated transcriptomic and metabolomic analyses show extensive reprogramming of cell‑wall genes and central energy metabolism, indicating that AT4G33780 coordinates metabolic state with developmental regulation rather than controlling single pathways. These findings position AT4G33780 as a key regulator linking chloroplast metabolism, growth robustness, and stress adaptation.

The study reveals that Arabidopsis B4‑subgroup RAF kinases possess intrinsically disordered regions that directly sense ionic and non‑ionic hyperosmolarity through reversible condensation, recruiting subclass‑I SnRK2s to activate them while avoiding PP2C inhibition. This osmosensing module can be reconstituted in E. coli or in vitro and appears to represent a conserved mechanism across kingdoms.