The study employed ultra large‑scale 2D clinostats to grow tomato (Solanum lycopersicum) plants beyond the seedling stage under simulated microgravity and upright control conditions across five sequential trials. Simulated microgravity consistently affected plant growth, but the magnitude and direction of the response varied among trials, with temperature identified as a significant co‑variant; moderate heat stress surprisingly enhanced growth under simulated microgravity. These results highlight the utility of large‑scale clinostats for dissecting interactions between environmental factors and simulated microgravity in plant development.
The study demonstrates that the interaction between spliceosomal proteins STA1 and DOT2 controls nuclear speckle organization, pre‑mRNA splicing efficiency, and heat‑stress tolerance in Arabidopsis thaliana. A missense mutation in DOT2 restores the weakened STA1‑DOT2 interaction in the sta1‑1 mutant, linking interaction strength to speckle formation and transcriptome‑wide intron retention under heat stress, while pharmacological inhibition of STA1‑associated speckles reproduces the mutant phenotypes. These findings reveal a heat‑sensitive interaction node that couples spliceosome assembly to nuclear speckle dynamics and splicing robustness.
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 binding assays showed that mutations at S49 and S52 disrupt GTP/GDP binding, while in vivo analyses revealed that distinct phosphomutants differentially rescue gpa1 null phenotypes, supporting a multi‑state signaling model for plant G proteins.
Complex regulation of RETINOBLASTOMA-RELATED's interactions with E2Fs via phosphorylation
Authors: Magyar, Z., Pettko-Szandtner, A., Vadai-Nagy, F., Gombos, M., Hlacs, A., Molnar, E., Marton, A., Vizler, C., Shiekh Bin Hamid, R., Kalo, P., Feher, A.
The study maps CDK-mediated phosphorylation of Arabidopsis RBR, revealing that while many phosphorylated forms still bind E2Fs, multi‑phosphorylated RBR with a phosphorylated S911 site loses association with E2Fs and DREAM components and instead binds RNA‑binding proteins linked to ribosome biogenesis and translation. S911 phosphorylation is enriched in proliferating cells and rapidly declines after DNA damage, suggesting it switches RBR from a proliferation to a quiescence role, and molecular modeling indicates this site becomes inaccessible when RBR is complexed with E2Fs.
A novel pathosystem between Aeschynomene evenia and Aphanomyces euteiches reveals new immune components in quantitative legume root-rot resistance.
Authors: Baker, M., Martinez, Y., Keller, J., Sarrette, B., Pervent, M., Libourel, C., Le Ru, A., Bonhomme, M., Gough, C., Castel, B., ARRIGHI, J.-F., Jacquet, C.
The study establishes Aeschynomene evenia as a new model for dissecting legume immunity against the soilborne pathogen Aphanomyces euteiches and its relationship with Nod factor-independent symbiosis. Quantitative resistance was assessed through inoculation assays, phenotypic and cytological analyses, and RNA‑seq identified thousands of differentially expressed genes, highlighting immune signaling and specialized metabolism, with mutant analysis confirming dual‑function kinases that modulate resistance. Comparative transcriptomics with Medicago truncatula revealed conserved and unique immune responses, positioning the A. evenia–A. euteiches system as a valuable platform for exploring quantitative resistance and symbiosis integration.
The study used genome‑wide ribosome profiling together with RNA‑seq to dissect translational regulation during the shift from seed dormancy to germination in Arabidopsis thaliana. It found that dormant seeds maintain a poised translational state with ribosomes pre‑positioned on stored mRNAs, and that selective changes in translational efficiency—particularly involving uORF‑mediated repression—drive germination independent of transcript levels. Functional assays confirmed that specific uORFs act as translational checkpoints during early imbibition.
The study reveals that the microtubule-associated protein MAP70-2 integrates mechanical and biochemical signals to guide division plane orientation during early lateral root primordium formation in Arabidopsis thaliana. Dynamic MAP70-2 localization to cell corners and the cortical division zone precedes cytokinesis, and loss of MAP70-2 results in misoriented divisions and malformed lateral roots, highlighting its role in three‑dimensional differential growth under mechanical constraints.
Botrytis cinerea mutants engineered to constitutively express the salicylate‑hydroxylase NahG grew better on salicylic‑acid media and showed heightened virulence on Arabidopsis thaliana and Phaseolus vulgaris, an effect that required host SA biosynthesis. Genomic analysis identified four fungal salicylate‑hydroxylase‑like genes whose expression varied during infection, suggesting B. cinerea can degrade host SA to promote colonization.
The study generated a dataset of 420 sgRNAs targeting promoters, exons, and introns of 137 tomato genes in protoplasts, linking editing efficiency to chromatin accessibility, genomic context, and sequence features. Open chromatin sites showed higher editing rates, while transcriptional activity had little effect, and a subset of guides produced near‑complete editing with microhomology‑mediated deletions. Human‑trained prediction models performed poorly, highlighting the need for plant‑specific guide design tools.
The study reveals that the Kelch phosphatase BSU1, previously thought to act as a tyrosine phosphatase in brassinosteroid signaling, actually functions as a PP1-like serine/threonine phosphatase whose activity is inhibited by CDK-mediated phosphorylation of its C‑terminal tail. Structural analysis, mutagenesis, and genetic experiments in Arabidopsis and Marchantia demonstrate that this regulatory mechanism links BSU1 to cell‑cycle control, affecting stomatal patterning, fertility, and undifferentiated cell mass formation.