bims-plasge 2025-05-11 papers

Issue of 2025–05–11
three papers selected by
Vera S. Bogdanova, ИЦиГ СО РАН

Plant Physiol. 2025 May 07. pii: kiaf187. [Epub ahead of print]

The pentatricopeptide repeat protein PPR767 modulates plant architecture and drought resistance in rice.

Leilei Peng, Haijun Xiao, Yanghong Xu, Zhihao Huang, Xuan Yang, Chen Lv, Linghui Huang, Jun Hu.

The RNA-binding proteins (RBPs) encoded by the nucleus are essential for RNA metabolism in eukaryotes. Pentatricopeptide repeat (PPR) proteins, a large subset of RBPs, are essential for plant development and reproduction by participating in organellar RNA processing. Here, we identified an E-type PPR protein, PPR767, which functions in mitochondria. Knocking out PPR767 resulted in decreased plant height, thinner stems, shorter and narrower blades, and consequently affected yield traits compared to those of the wild-type. PPR767 primarily participated in the RNA editing of four sites related to NADH dehydrogenase (Nad), including nad1-674, nad3-155, nad3-172, and nad7-317. PPR767 interacted with multiple organellar RNA editing factors (MORFs), including MORF1 and MORF8, suggesting that the editosome in rice (Oryza sativa) is complex. The mutants showed decreased mitochondrial complex Ⅰ activity and compromised mitochondrial structure. Furthermore, mutation of PPR767 influenced rice drought tolerance and the expression levels of genes involved in reactive oxygen species (ROS) accumulation. Therefore, PPR767 is essential for complex Ⅰ activity by properly regulating the RNA editing efficiency of mitochondrial genes and affects drought tolerance by modulating ROS content in rice. Our findings provide valuable insights into the mechanisms by which PPRs fulfil their functions.

Keywords: RNA editing; ROS; complex Ⅰ; drought resistance; mitochondria; pentatricopeptide repeat; rice

DOI: https://doi.org/10.1093/plphys/kiaf187

Nat Commun. 2025 May 08. 16(1): 4266

A nuclear-encoded endonuclease governs the paternal transmission of mitochondria in Cucumis plants.

Jia Shen, Xiaolong Lyu, Xinyang Xu, Zheng Wang, Yuejian Zhang, Chenhao Wang, Eduardo D Munaiz, Mingfang Zhang, Michael J Havey, Weisong Shou.

Non-Mendelian transmission of mitochondria has been well established across most eukaryotes, however the genetic mechanism that governs this uniparental inheritance remains unclear. Plants in the genus Cucumis, specifically melon and cucumber, exhibit paternal transmission of the mitochondrial (mt) DNA, making them excellent models for exploring the molecular mechanisms underlying mitochondrial transmission. Here, we develop a toolkit to screen for mutants in mitochondrial inheritance (mti), and use fine mapping to successfully identify a mitochondrially targeted endonuclease gene (MTI1) controlling mitochondrial transmission. Knockout of MTI1 results in a shift from paternal to bi-parental inheritance of the mtDNA, confirming the crucial role of MTI1 in uniparental inheritance of mitochondria. Moreover, we demonstrate that MTI1 exhibits robust endonuclease activity both in vitro and in vivo, specifically expresses in mitochondria of the fertilized ovule within 24 h of pollination. Collectively, this study reveals that a nuclear-encoded but mitochondria-targeted gene plays a causative role in governing the non-Mendelian mitochondrial inheritance, revolutionizing our knowledge about mitochondrial DNA transmission.

DOI: https://doi.org/10.1038/s41467-025-59568-7

Am J Bot. 2025 May 06. e70039

Disentangling serial chloroplast captures in willows.

Diksha Gambhir, Brian J Sanderson, Minghao Guo, Nan Hu, Ashmita Khanal, Quentin Cronk, Tao Ma, Jianquan Liu, Diana M Percy, Matthew S Olson.

PREMISE: Chloroplast capture is a process through which the chloroplast of a focal species is replaced by the chloroplast from another species during repeated backcrossing of an initial hybrid. Here we investigated serial chloroplast capture from Salix nigra in willows during sequential hybridization events that led to the capture of the same chloroplast lineage across multiple Salix species.
METHODS: Previously generated sequences of nuclear and chloroplast regions from several Salix species were used to identify cases of cytonuclear phylogenetic discordance, a pattern indicating chloroplast capture. Serial chloroplast captures were identified by comparing phylogenetic topologies of the chloroplast trees to discriminate among (1) a single chloroplast capture and subsequent speciation of the lineage with the captured chloroplast, (2) multiple chloroplast captures from the same parent species, and (3) serial chloroplast captures. We also looked for hybridization in genes involved in cytonuclear interactions and in photosynthesis.
RESULTS: We identified cases of serial chloroplast capture and speciation after chloroplast capture in Salix. Although these chloroplast capture events were accompanied by signals of hybridization in the nuclear genomes, nuclear genes that functionally interact with chloroplast genes and nuclear genes involved in photosynthesis were no more likely to introgress in species with chloroplast captures than in species without chloroplast captures.
CONCLUSIONS: This study illuminates the complex evolution of the chloroplast genomes in Salix and the potential for hybridization and introgression to influence genomic evolution.

Keywords: Salicaceae; Salix; ancient hybridization; chloroplast capture; cytonuclear incongruence; introgression; phylogenomics; willows

DOI: https://doi.org/10.1002/ajb2.70039