Genetius

The study integrates multi-omics data from six Sorghum bicolor accessions under field drought to link RNA covalent modifications (RCMs) with photosynthetic performance, identifying the enzyme SbDUS2 that produces dihydrouridine (DHU) on transcripts. Loss‑of‑function dus2 mutants in Arabidopsis thaliana reveal that DHU deficiency leads to hyperstability of photosynthesis‑related mRNAs, impairing germination, development, and stress‑induced CO2 assimilation. The authors propose DHU as a post‑transcriptional mark that promotes rapid mRNA turnover during abiotic stress, enhancing plant resilience.

Arabidopsis mutants lacking m6A writer or reader proteins are hypersensitive to salt, while salt stress triggers a genome‑wide increase and redistribution of m6A, especially near stop codons and 3′‑UTRs. Integrating MeRIP‑seq with expression data reveals that many salt‑responsive genes, notably those in the photosynthesis pathway, acquire higher m6A marks concomitant with reduced expression via accelerated mRNA decay, leading to impaired chloroplast function.

The study identifies Chloroplast Lipid Remodeling Protein 23 (CLRP23) as an inner envelope membrane protein that faces the intermembrane space and directly binds chloroplast lipids. Mutants lacking CLRP23 show impaired photosynthesis and altered galactolipid composition under cold stress, indicating its role in lipid remodeling during cold acclimation. Integrated transcriptomic and proteomic data further support CLRP23’s contribution to broader cold‑responsive pathways.

The authors present a live‑cell imaging platform that couples genetically encoded fluorescent biosensors with on‑stage illumination to track pH, MgATP²⁻, and NADH/NAD⁺ dynamics during dark‑light transitions in Arabidopsis mesophyll cells. They reveal that photosynthetic proton pumping triggers an alkalinization wave extending from the chloroplast stroma to the cytosol and mitochondria, raises MgATP²⁻ levels, and drives reduction of the NAD pool, with malate dehydrogenases modulating cytosolic redox status. This methodology establishes a high‑resolution standard for monitoring photosynthetic physiology across cellular compartments.

The study compared photosynthetic performance and carbon metabolism in mature versus immature leaves of Arabidopsis thaliana accessions from different latitudes under standard and low‑temperature/high‑light conditions. Leaf‑specific measurements of Fv/Fm and CO2 assimilation revealed distinct acclimation capacities, and integration of carbohydrate and carboxylic‑acid profiles into a carbon balance model indicated that mature leaves help stabilize metabolism in younger tissue. The authors emphasize the importance of accounting for intra‑rosette heterogeneity to avoid misleading metabolic interpretations.

The study demonstrates that chloroplast‑derived hydrogen peroxide (H2O2) acts as a signal linking photosynthesis to stomatal movements, with elevated H2O2 in the apx1 mutant causing increased stomatal opening. Reducing photosynthetic H2O2 production rescues this phenotype, and cell‑specific complementation shows that H2O2 signals from both guard cells and mesophyll cells are crucial for coordination of stomatal conductance and photosynthesis.