bims-plasge 2024-12-08 papers

Issue of 2024–12–08
two papers selected by
Vera S. Bogdanova, ИЦиГ СО РАН

Adv Sci (Weinh). 2024 Dec 04. e2405131

RNA Polymerase RPOTp is Involved in C-to-U RNA Editing at Multiple Sites in Arabidopsis Chloroplasts.

Nadia Ahmed Ali, Wenjian Song, Yayi Zhang, Jiani Xing, Kexing Su, Xingxing Sun, Yujia Sun, Yizhou Jiang, Dianxing Wu, Xiaobo Zhao.

RPOTp is the nuclear-encoded plastid-targeted RNA polymerase and plays a crucial role in chloroplast gene expression. Transcripts in plant organelles are altered by the conversion of cytidine (C) to uridine (U) at specific positions through RNA editing. However, whether RPOTp is involved in chloroplast RNA editing remains unclear. Here, the role of RPOTp in C-to-U RNA editing at multiple sites in Arabidopsis chloroplasts is uncovered. Multiple organellar RNA editing factor 2 (MORF2) is required for the editing of most sites in chloroplasts. RPOTp is identified from the co-immunoprecipitation targets of MORF2. The sca3-2 mutant, defective in RPOTp, exhibits a pale-yellow phenotype and alters the RNA editing of nine sites in chloroplasts. It is also shown that RNA editing is uncoupled from chloroplast transcriptional activity. RPOTp directly interacts with chloroplast multiple-site RNA editing factors, including MORF2, MORF8, MORF9, and ORRM1. It is further shown that RPOTp participates in RNA editing by influencing the dimerization of MORF proteins. The defect in RPOTp impairs the expression of most chloroplast genes, indicating an indispensable role for RPOTp in chloroplast gene expression. These findings reveal that RPOTp not only participates in transcription but also has a novel role in RNA editing of chloroplast transcripts.

Keywords: MORF; RNA editing; RNA polymerase; RPOTp; chloroplast

DOI: https://doi.org/10.1002/advs.202405131

Theor Appl Genet. 2024 Dec 03. 138(1): 1

A β-ketoacyl-CoA synthase encoded by DDP1 controls rice anther dehiscence and pollen fertility by maintaining lipid homeostasis in the tapetum.

Yibo Xu, Shixu Zhou, Jingfei Tian, Wenfeng Zhao, Jianxin Wei, Juan He, Wenye Tan, Lianguang Shang, Xinhua He, Rongbai Li, Yongfei Wang, Baoxiang Qin.

KEY MESSAGE: DDP1, encoding a β-Ketoacyl-CoA Synthase, regulates rice anther dehiscence and pollen fertility by affecting the deposition of lipid on anther epidermis and pollen wall. Anther dehiscence and pollen fertility are crucial for male fertility in rice. Here, we studied the function of Defective in Dehiscence and Pollen1 (DDP1), a novel member of the KCS family in rice, in regulating anther dehiscence and pollen fertility. DDP1 encodes an endoplasmic reticulum (ER)-localized protein and is ubiquitously expressed in various organs, predominately in the microspores and tapetum. The ddp1 mutant exhibited partial male sterility attributed to defective anther dehiscence and pollen fertility, which was notably distinct from those observed in Arabidopsis thaliana and rice mutants associated with lipid metabolism. Mutations of DDP1 altered the content and composition of wax on anther epidermis and pollen wall, causing abnormalities in their morphology. Moreover, genes implicated in lipid metabolism, pollen development, and anther dehiscence exhibited significantly altered expression levels in the ddp1 mutant. These findings indicate that DDP1 controls anther dehiscence and pollen fertility to ensure normal male development by modulating lipid homeostasis in the tapetum, thereby enhancing our understanding of the mechanisms underlying rice anther dehiscence and pollen fertility.

DOI: https://doi.org/10.1007/s00122-024-04786-8