bims-plasge 2025-03-30 papers

Issue of 2025–03–30
three papers selected by
Vera S. Bogdanova, ИЦиГ СО РАН

Int J Mol Sci. 2025 Mar 14. pii: 2646. [Epub ahead of print]26(6):

The Pentatricopeptide Repeat Protein OsPPR674 Regulates Rice Growth and Drought Sensitivity by Modulating RNA Editing of the Mitochondrial Transcript ccmC.

Jinglei Li, Longhui Zhang, Chenyang Li, Weijun Chen, Tiankang Wang, Lvni Tan, Yingxin Qiu, Shufeng Song, Bin Li, Li Li.

The P-type pentatricopeptide repeat (PPR) proteins are crucial for RNA editing and post-transcriptional regulation in plant organelles, particularly mitochondria. This study investigates the role of OsPPR674 in rice, focusing on its function in mitochondrial RNA editing. Using CRISPR/Cas9 technology, we generated ppr674 mutant and examined its phenotypic and molecular characteristics. The results indicate that ppr674 exhibits reduced plant height, decreased seed-setting rate, and poor drought tolerance. Further analysis revealed that in the ppr674 mutant, RNA editing at the 299th nucleotide position of the mitochondrial ccmC gene (C-to-U conversion) was abolished. REMSAs showed that GST-PPR674 specifically binds to RNA probes targeting this ccmC-299 site, confirming its role in this editing process. In summary, these results suggest that OsPPR674 plays a pivotal role in mitochondrial RNA editing, emphasizing the significance of PPR proteins in organelle function and plant development.

Keywords: PPR protein; RNA editing; drought stress adaptation; molecular breeding; rice (Oryza sativa L.)

DOI: https://doi.org/10.3390/ijms26062646

Int J Mol Sci. 2025 Mar 14. pii: 2612. [Epub ahead of print]26(6):

A Suite of Pea (Pisum sativum L.) Near-Isolines: Genetic Resources and Molecular Tools to Breed for Seed Carbohydrate and Protein Quality in Legumes.

Tracey Rayner, Julia E A Mundy, Lorelei J Bilham, Carol Moreau, David M Lawson, Claire Domoney, Trevor L Wang.

In recent years there has been a resurgent interest in plant products as substitutes for animal-derived food products, in which legumes, including peas, feature highly. Here, we report on a set of Pisum sativum L. (pea) near-isolines, comprising 24 unique mutants at five loci, where the impact of the mutations on the corresponding enzymes of the starch pathway confers a wrinkled-seeded phenotype. Together with a set of round-seeded mutants impacted at a sixth locus, all 27 mutants show variation for starch composition and protein content. The mutations have been mapped onto three-dimensional protein models to examine potential effects on the corresponding enzyme structures and their activities, and to guide targeted mutagenesis. The mutant lines represent a unique suite of alleles for rapid introduction into elite pea varieties to create new materials for the food and feed markets and industrial applications.

Keywords: Pisum sativum; amylopectin; amylose; breeding; legumes; modelling; mutant; pea; protein; starch

DOI: https://doi.org/10.3390/ijms26062612

Nucleic Acids Res. 2025 Mar 20. pii: gkaf222. [Epub ahead of print]53(6):

Targeted translation inhibition of chloroplast and mitochondrial mRNAs by designer pentatricopeptide repeat proteins.

Nikolay Manavski, Serena Schwenkert, Hans-Henning Kunz, Dario Leister, Jörg Meurer.

Pentatricopeptide repeat (PPR) proteins are crucial for organellar gene expression. To establish a tool for gene expression manipulation in Arabidopsis plastids and genetically inaccessible mitochondria, we engineered designer (dPPR) proteins to specifically inhibit the translation of organellar mRNAs by masking their start codons. Unlike prior methods for targeted downregulation of gene expression, which rely on re-targeting native PPR proteins to RNA sequences closely related to their original targets, our approach employs a synthetic P-type PPR scaffold that can be designed to bind any RNA sequence of interest. Here, using dPPR-psbK and dPPR-nad7, we targeted the psbK mRNA in chloroplasts and the nad7 mRNA in mitochondria, respectively. dPPR-psbK effectively bound to psbK mRNA and inhibited its translation with high specificity, resulting in disrupted PSII supercomplexes and reduced photosynthetic efficiency. dPPR-nad7 suppressed nad7 translation, affecting NADH oxidase activity in complex I and growth retardation. Comparing phenotypes with tobacco psbK knockouts and nad7 knockdown bir6-2 mutants, along with quantitative proteomics, showed no clear evidence of physiologically relevant off-target effects. Our findings establish dPPR proteins as precise tools for targeted translation inhibition, facilitating functional studies of organellar genes and offering a novel approach with potential for manipulating organellar gene expression in diverse plant species.

DOI: https://doi.org/10.1093/nar/gkaf222