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Schmid LM, Manavski N, Chi W, Meurer J. Chloroplast Ribosome Biogenesis Factors. PLANT & CELL PHYSIOLOGY 2024; 65:516-536. [PMID: 37498958 DOI: 10.1093/pcp/pcad082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/13/2023] [Accepted: 07/25/2023] [Indexed: 07/29/2023]
Abstract
The formation of chloroplasts can be traced back to an ancient event in which a eukaryotic host cell containing mitochondria ingested a cyanobacterium. Since then, chloroplasts have retained many characteristics of their bacterial ancestor, including their transcription and translation machinery. In this review, recent research on the maturation of rRNA and ribosome assembly in chloroplasts is explored, along with their crucial role in plant survival and their implications for plant acclimation to changing environments. A comparison is made between the ribosome composition and auxiliary factors of ancient and modern chloroplasts, providing insights into the evolution of ribosome assembly factors. Although the chloroplast contains ancient proteins with conserved functions in ribosome assembly, newly evolved factors have also emerged to help plants acclimate to changes in their environment and internal signals. Overall, this review offers a comprehensive analysis of the molecular mechanisms underlying chloroplast ribosome assembly and highlights the importance of this process in plant survival, acclimation and adaptation.
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Affiliation(s)
- Lisa-Marie Schmid
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Street 2-4, Planegg-Martinsried 82152, Germany
| | - Nikolay Manavski
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Street 2-4, Planegg-Martinsried 82152, Germany
| | - Wei Chi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jörg Meurer
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Street 2-4, Planegg-Martinsried 82152, Germany
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2
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Wang Y, Wang D, Du J, Wang Y, Shao C, Cui C, Xiao J, Wang X. Crucial role of SWL1 in chloroplast biogenesis and development in Arabidopsis thaliana. PLANT CELL REPORTS 2024; 43:135. [PMID: 38704787 DOI: 10.1007/s00299-024-03210-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Accepted: 04/01/2024] [Indexed: 05/07/2024]
Abstract
KEY MESSAGE The disruption of the SWL1 gene leads to a significant down regulation of chloroplast and secondary metabolites gene expression in Arabidopsis thaliana. And finally results in a dysfunction of chloroplast and plant growth. Although the development of the chloroplast has been a consistent focus of research, the corresponding regulatory mechanisms remain unidentified. In this study, the CRISPR/Cas9 system was used to mutate the SWL1 gene, resulting in albino cotyledons and variegated true leaf phenotype. Confocal microscopy and western blot of chloroplast protein fractions revealed that SWL1 localized in the chloroplast stroma. Electron microscopy indicated chloroplasts in the cotyledons of swl1 lack well-defined grana and internal membrane structures, and similar structures have been detected in the albino region of variegated true leaves. Transcriptome analysis revealed that down regulation of chloroplast and nuclear gene expression related to chloroplast, including light harvesting complexes, porphyrin, chlorophyll metabolism and carbon metabolism in the swl1 compared to wild-type plant. In addition, proteomic analysis combined with western blot analysis, showed that a significant decrease in chloroplast proteins of swl1. Furthermore, the expression of genes associated with secondary metabolites and growth hormones was also reduced, which may be attributed to SWL1 associated with absorption and fixation of inorganic carbon during chloroplast development. Together, the above findings provide valuable information to elucidate the exact function of SWL1 in chloroplast biogenesis and development.
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Affiliation(s)
- Yue Wang
- State Key Laboratory of Efficient Production of Forest Resources, Beijing Forestry University, Beijing, 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China
| | - Dong Wang
- State Key Laboratory of Efficient Production of Forest Resources, Beijing Forestry University, Beijing, 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China
| | - Jingxia Du
- State Key Laboratory of Efficient Production of Forest Resources, Beijing Forestry University, Beijing, 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China
| | - Yan Wang
- College of Agriculture and Forestry, Hebei North University, Zhangjiakou, 075000, China
| | - Chunxue Shao
- State Key Laboratory of Efficient Production of Forest Resources, Beijing Forestry University, Beijing, 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China
| | - Chuwen Cui
- State Key Laboratory of Efficient Production of Forest Resources, Beijing Forestry University, Beijing, 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China
| | - Jianwei Xiao
- State Key Laboratory of Efficient Production of Forest Resources, Beijing Forestry University, Beijing, 100083, China.
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China.
| | - Xinwei Wang
- College of Agriculture and Forestry, Hebei North University, Zhangjiakou, 075000, China.
- SENO Biotechnology Co., Ltd., Zhangjiakou, 075000, China.
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3
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McCray TN, Azim MF, Burch-Smith TM. The dicot homolog of maize PPR103 carries a C-terminal DYW domain and may have a role in C-to-U editing of some chloroplast RNA transcripts. PLANT MOLECULAR BIOLOGY 2024; 114:28. [PMID: 38485794 PMCID: PMC10940495 DOI: 10.1007/s11103-024-01424-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 01/30/2024] [Indexed: 03/18/2024]
Abstract
In plants, cytidine-to-uridine (C-to-U) editing is a crucial step in processing mitochondria- and chloroplast-encoded transcripts. This editing requires nuclear-encoded proteins including members of the pentatricopeptide (PPR) family, especially PLS-type proteins carrying the DYW domain. IPI1/emb175/PPR103 is a nuclear gene encoding a PLS-type PPR protein essential for survival in Arabidopsis thaliana and maize. Arabidopsis IPI1 was identified as likely interacting with ISE2, a chloroplast-localized RNA helicase associated with C-to-U RNA editing in Arabidopsis and maize. Notably, while the Arabidopsis and Nicotiana IPI1 orthologs possess complete DYW motifs at their C-termini, the maize homolog, ZmPPR103, lacks this triplet of residues which are essential for editing. In this study we examined the function of IPI1 in chloroplast RNA processing in N. benthamiana to gain insight into the importance of the DYW domain to the function of the EMB175/PPR103/ IPI1 proteins. Structural predictions suggest that evolutionary loss of residues identified as critical for catalyzing C-to-U editing in other members of this class of proteins, were likely to lead to reduced or absent editing activity in the Nicotiana and Arabidopsis IPI1 orthologs. Virus-induced gene silencing of NbIPI1 led to defects in chloroplast ribosomal RNA processing and changes to stability of rpl16 transcripts, revealing conserved function with its maize ortholog. NbIPI1-silenced plants also had defective C-to-U RNA editing in several chloroplast transcripts, a contrast from the finding that maize PPR103 had no role in editing. The results indicate that in addition to its role in transcript stability, NbIPI1 may contribute to C-to-U editing in N. benthamiana chloroplasts.
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Affiliation(s)
- Tyra N McCray
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Mohammad F Azim
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
| | - Tessa M Burch-Smith
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA.
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA.
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA.
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4
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Hua HY, Santibanez PI, Ngo VT, Hayes ML. RIP-Seq analysis of non-PPR chloroplast editing factors reveals broad RNA interactions and enrichment of less efficiently translated RNAs by OZ1 and ORRM1 complexes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:1528-1542. [PMID: 38088241 PMCID: PMC10922338 DOI: 10.1111/tpj.16581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 11/22/2023] [Accepted: 11/26/2023] [Indexed: 02/28/2024]
Abstract
C-to-U RNA editing in angiosperm chloroplasts requires a large suite of proteins bound together in the editosome. The editosome is comprised of PPR proteins, RIP/MORFs, OZ proteins, and ORRM proteins that physically interact in high molecular weight complexes. The specific functions of non-PPR editing factors in the editosome are unclear, however, specific subsets of editing sites are affected by absence of non-PPR editing factors. Unlike the PPR components of editosomes that have predictable nucleotide specificities, domains present in non-PPR editing factors make RNA associations difficult to predict. In this study, chloroplast extracts were isolated from juvenile maize seedlings. RNAs were immunoprecipitated using polyclonal antibodies targeting non-PPR editing factors RIP9, OZ1, and ORRM1. RNA libraries from duplicate experiments were compared. RIP9 was associated with most of the non-ribosomal RNA content of chloroplasts, consistent with a general binding function to PPR L-motifs and tethering of large ribonucleoprotein complexes. The breadth of RNA associations was greater than predicted and include mRNAs without predicted editing sites, tRNA sequences, and introns. OZ1 and ORRM1 were associated with a highly similar pool of RNAs that have a bias toward lower translational efficiency values in mature chloroplasts. Lower translational efficiency was also associated with the pool of edited RNAs compared to RNAs without editing sites. The unexpected breadth of interactions by non-PPR editing factors suggests the editosome is large, diverse, and associated with RNAs with lower relative translational efficiency in mature chloroplasts.
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Affiliation(s)
- Hope Y. Hua
- Department of Chemistry and Biochemistry, California State University Los Angeles, Los Angeles, California, 90032, USA
| | - Paola I. Santibanez
- Department of Chemistry and Biochemistry, California State University Los Angeles, Los Angeles, California, 90032, USA
| | - Vinh T. Ngo
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, 90840, USA
| | - Michael L. Hayes
- Department of Chemistry and Biochemistry, California State University Los Angeles, Los Angeles, California, 90032, USA
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5
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Kafri M, Patena W, Martin L, Wang L, Gomer G, Ergun SL, Sirkejyan AK, Goh A, Wilson AT, Gavrilenko SE, Breker M, Roichman A, McWhite CD, Rabinowitz JD, Cross FR, Wühr M, Jonikas MC. Systematic identification and characterization of genes in the regulation and biogenesis of photosynthetic machinery. Cell 2023; 186:5638-5655.e25. [PMID: 38065083 PMCID: PMC10760936 DOI: 10.1016/j.cell.2023.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 08/03/2023] [Accepted: 11/03/2023] [Indexed: 12/18/2023]
Abstract
Photosynthesis is central to food production and the Earth's biogeochemistry, yet the molecular basis for its regulation remains poorly understood. Here, using high-throughput genetics in the model eukaryotic alga Chlamydomonas reinhardtii, we identify with high confidence (false discovery rate [FDR] < 0.11) 70 poorly characterized genes required for photosynthesis. We then enable the functional characterization of these genes by providing a resource of proteomes of mutant strains, each lacking one of these genes. The data allow assignment of 34 genes to the biogenesis or regulation of one or more specific photosynthetic complexes. Further analysis uncovers biogenesis/regulatory roles for at least seven proteins, including five photosystem I mRNA maturation factors, the chloroplast translation factor MTF1, and the master regulator PMR1, which regulates chloroplast genes via nuclear-expressed factors. Our work provides a rich resource identifying regulatory and functional genes and placing them into pathways, thereby opening the door to a system-level understanding of photosynthesis.
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Affiliation(s)
- Moshe Kafri
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Weronika Patena
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Lance Martin
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Lianyong Wang
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Gillian Gomer
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Sabrina L Ergun
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA
| | - Arthur K Sirkejyan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Audrey Goh
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Alexandra T Wilson
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Sophia E Gavrilenko
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Michal Breker
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York, NY 10021, USA
| | - Asael Roichman
- Lewis-Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Claire D McWhite
- Lewis-Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Joshua D Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Frederick R Cross
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York, NY 10021, USA
| | - Martin Wühr
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Martin C Jonikas
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA.
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6
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Li ZA, Li Y, Liu D, Molloy DP, Luo ZF, Li HO, Zhao J, Zhou J, Su Y, Wang RZ, Huang C, Xiao LT. YUCCA2 (YUC2)-Mediated 3-Indoleacetic Acid (IAA) Biosynthesis Regulates Chloroplast RNA Editing by Relieving the Auxin Response Factor 1 (ARF1)-Dependent Inhibition of Editing Factors in Arabidopsis thaliana. Int J Mol Sci 2023; 24:16988. [PMID: 38069311 PMCID: PMC10706925 DOI: 10.3390/ijms242316988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/24/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
Although recent research progress on the abundant C-to-U RNA editing events in plant chloroplasts and mitochondria has uncovered many recognition factors and their molecular mechanisms, the intrinsic regulation of RNA editing within plants remains largely unknown. This study aimed to establish a regulatory relationship in Arabidopsis between the plant hormone auxin and chloroplast RNA editing. We first analyzed auxin response elements (AuxREs) present within promoters of chloroplast editing factors reported to date. We found that each has more than one AuxRE, suggesting a potential regulatory role of auxin in their expression. Further investigation unveiled that the depletion of auxin synthesis gene YUC2 reduces the expression of several editing factors. However, in yuc2 mutants, only the expression of CRR4, DYW1, ISE2, and ECD1 editing factors and the editing efficiency of their corresponding editing sites, ndhD-2 and rps14-149, were simultaneously suppressed. In addition, exogenous IAA and the overexpression of YUC2 enhanced the expression of these editing factors and the editing efficiency at the ndhD-2 and rps14-149 sites. These results suggested a direct effect of auxin upon the editing of the ndhD-2 and rps14-149 sites through the modulation of the expression of the editing factors. We further demonstrated that ARF1, a downstream transcription factor in the auxin-signaling pathway, could directly bind to and inactivate the promoters of CRR4, DYW1, and ISE2 in a dual-luciferase reporter system, thereby inhibiting their expression. Moreover, the overexpression of ARF1 in Arabidopsis significantly reduced the expression of the three editing factors and the editing efficiency at the ndhD-2 and rps14-149 sites. These data suggest that YUC2-mediated auxin biosynthesis governs the RNA-editing process through the ARF1-dependent signal transduction pathway.
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Affiliation(s)
- Zi-Ang Li
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
| | - Yi Li
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
| | - Dan Liu
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
| | - David P. Molloy
- Department of Basic Medicine, Chongqing Medical University, Chongqing 400016, China;
| | - Zhou-Fei Luo
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
| | - Hai-Ou Li
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
| | - Jing Zhao
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
| | - Jing Zhou
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
| | - Yi Su
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
| | - Ruo-Zhong Wang
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
| | - Chao Huang
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
| | - Lang-Tao Xiao
- Hunan Provincial Key Laboratory of Phytohormones and Growth Development, Hunan Agricultural University, Changsha 410128, China; (Z.-A.L.); (Y.L.); (D.L.); (Z.-F.L.); (H.-O.L.); (J.Z.); (J.Z.); (Y.S.); (R.-Z.W.)
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7
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Girasol MJ, Briggs EM, Marques CA, Batista JM, Beraldi D, Burchmore R, Lemgruber L, McCulloch R. Immunoprecipitation of RNA-DNA hybrid interacting proteins in Trypanosoma brucei reveals conserved and novel activities, including in the control of surface antigen expression needed for immune evasion by antigenic variation. Nucleic Acids Res 2023; 51:11123-11141. [PMID: 37843098 PMCID: PMC10639054 DOI: 10.1093/nar/gkad836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 09/14/2023] [Accepted: 09/28/2023] [Indexed: 10/17/2023] Open
Abstract
RNA-DNA hybrids are epigenetic features of genomes that provide a diverse and growing range of activities. Understanding of these functions has been informed by characterising the proteins that interact with the hybrids, but all such analyses have so far focused on mammals, meaning it is unclear if a similar spectrum of RNA-DNA hybrid interactors is found in other eukaryotes. The African trypanosome is a single-cell eukaryotic parasite of the Discoba grouping and displays substantial divergence in several aspects of core biology from its mammalian host. Here, we show that DNA-RNA hybrid immunoprecipitation coupled with mass spectrometry recovers 602 putative interactors in T. brucei mammal- and insect-infective cells, some providing activities also found in mammals and some lineage-specific. We demonstrate that loss of three factors, two putative helicases and a RAD51 paralogue, alters T. brucei nuclear RNA-DNA hybrid and DNA damage levels. Moreover, loss of each factor affects the operation of the parasite immune survival mechanism of antigenic variation. Thus, our work reveals the broad range of activities contributed by RNA-DNA hybrids to T. brucei biology, including new functions in host immune evasion as well as activities likely fundamental to eukaryotic genome function.
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Affiliation(s)
- Mark J Girasol
- University of Glasgow, College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, Glasgow, UK
- University of the Philippines Manila, College of Medicine, Manila, Philippines
| | - Emma M Briggs
- University of Glasgow, College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, Glasgow, UK
- University of Edinburgh, Institute for Immunology and Infection Research, School of Biological Sciences, Edinburgh, UK
| | - Catarina A Marques
- University of Glasgow, College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, Glasgow, UK
| | - José M Batista
- University of Glasgow, College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, Glasgow, UK
| | - Dario Beraldi
- University of Glasgow, College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, Glasgow, UK
| | - Richard Burchmore
- University of Glasgow, College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, Glasgow, UK
| | - Leandro Lemgruber
- University of Glasgow, College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, Glasgow, UK
| | - Richard McCulloch
- University of Glasgow, College of Medical, Veterinary and Life Sciences, School of Infection and Immunity, Wellcome Centre for Integrative Parasitology, Glasgow, UK
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8
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Yang YZ, Ding S, Liu XY, Xu C, Sun F, Tan BC. The DEAD-box RNA helicase ZmRH48 is required for the splicing of multiple mitochondrial introns, mitochondrial complex biosynthesis, and seed development in maize. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:2456-2468. [PMID: 37594235 DOI: 10.1111/jipb.13558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 08/16/2023] [Indexed: 08/19/2023]
Abstract
RNA helicases participate in nearly all aspects of RNA metabolism by rearranging RNAs or RNA-protein complexes in an adenosine triphosphate-dependent manner. Due to the large RNA helicase families in plants, the precise roles of many RNA helicases in plant physiology and development remain to be clarified. Here, we show that mutations in maize (Zea mays) DEAD-box RNA helicase 48 (ZmRH48) impair the splicing of mitochondrial introns, mitochondrial complex biosynthesis, and seed development. Loss of ZmRH48 function severely arrested embryogenesis and endosperm development, leading to defective kernel formation. ZmRH48 is targeted to mitochondria, where its deficiency dramatically reduced the splicing efficiency of five cis-introns (nad5 intron 1; nad7 introns 1, 2, and 3; and ccmFc intron 1) and one trans-intron (nad2 intron 2), leading to lower levels of mitochondrial complexes I and III. ZmRH48 interacts with two unique pentatricopeptide repeat (PPR) proteins, PPR-SMR1 and SPR2, which are required for the splicing of over half of all mitochondrial introns. PPR-SMR1 interacts with SPR2, and both proteins interact with P-type PPR proteins and Zm-mCSF1 to facilitate intron splicing. These results suggest that ZmRH48 is likely a component of a splicing complex and is critical for mitochondrial complex biosynthesis and seed development.
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Affiliation(s)
- Yan-Zhuo Yang
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Shuo Ding
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Xin-Yuan Liu
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Chunhui Xu
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Feng Sun
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Bao-Cai Tan
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
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9
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Zhang Y, Tian L, Lu C. Chloroplast gene expression: Recent advances and perspectives. PLANT COMMUNICATIONS 2023; 4:100611. [PMID: 37147800 PMCID: PMC10504595 DOI: 10.1016/j.xplc.2023.100611] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 04/11/2023] [Accepted: 05/01/2023] [Indexed: 05/07/2023]
Abstract
Chloroplasts evolved from an ancient cyanobacterial endosymbiont more than 1.5 billion years ago. During subsequent coevolution with the nuclear genome, the chloroplast genome has remained independent, albeit strongly reduced, with its own transcriptional machinery and distinct features, such as chloroplast-specific innovations in gene expression and complicated post-transcriptional processing. Light activates the expression of chloroplast genes via mechanisms that optimize photosynthesis, minimize photodamage, and prioritize energy investments. Over the past few years, studies have moved from describing phases of chloroplast gene expression to exploring the underlying mechanisms. In this review, we focus on recent advances and emerging principles that govern chloroplast gene expression in land plants. We discuss engineering of pentatricopeptide repeat proteins and its biotechnological effects on chloroplast RNA research; new techniques for characterizing the molecular mechanisms of chloroplast gene expression; and important aspects of chloroplast gene expression for improving crop yield and stress tolerance. We also discuss biological and mechanistic questions that remain to be answered in the future.
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Affiliation(s)
- Yi Zhang
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China
| | - Lin Tian
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China
| | - Congming Lu
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China.
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10
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Toma-Fukai S, Sawada Y, Maeda A, Shimizu H, Shikanai T, Takenaka M, Shimizu T. Structural insight into the activation of an Arabidopsis organellar C-to-U RNA editing enzyme by active site complementation. THE PLANT CELL 2023; 35:1888-1900. [PMID: 36342219 PMCID: PMC10226597 DOI: 10.1093/plcell/koac318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/05/2022] [Indexed: 05/30/2023]
Abstract
RNA-binding pentatricopeptide repeat (PPR) proteins catalyze hundreds of cytidine to uridine RNA editing events in plant organelles; these editing events are essential for proper gene expression. More than half of the PPR-type RNA editing factors, however, lack the DYW cytidine deaminase domain. Genetic analyses have suggested that their cytidine deaminase activity arises by association with a family of DYW1-like proteins that contain an N-terminally truncated DYW domain, but their molecular mechanism has been unclear. Here, we report the crystal structure of the Arabidopsis thaliana DYW1 deaminase domain at 1.8 Å resolution. DYW1 has a cytidine deaminase fold lacking the PG box. The internal insertion within the deaminase fold shows an α-helical fold instead of the β-finger reported for the gating domain of the A. thaliana ORGANELLE TRANSCRIPT PROCESSING 86. The substrate-binding pocket is incompletely formed and appears to be complemented in the complex by the E2 domain and the PG box of the interacting PPR protein. In vivo RNA editing assays corroborate the activation model for DYW1 deaminase. Our study demonstrates the common activation mechanism of the DYW1-like proteins by molecular complementation of the DYW domain and reconstitution of the substrate-binding pocket.
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Affiliation(s)
- Sachiko Toma-Fukai
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yuto Sawada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ayako Maeda
- Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Hikaru Shimizu
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Mizuki Takenaka
- Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Toshiyuki Shimizu
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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11
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Small I, Melonek J, Bohne AV, Nickelsen J, Schmitz-Linneweber C. Plant organellar RNA maturation. THE PLANT CELL 2023; 35:1727-1751. [PMID: 36807982 PMCID: PMC10226603 DOI: 10.1093/plcell/koad049] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/05/2023] [Accepted: 01/17/2023] [Indexed: 05/30/2023]
Abstract
Plant organellar RNA metabolism is run by a multitude of nucleus-encoded RNA-binding proteins (RBPs) that control RNA stability, processing, and degradation. In chloroplasts and mitochondria, these post-transcriptional processes are vital for the production of a small number of essential components of the photosynthetic and respiratory machinery-and consequently for organellar biogenesis and plant survival. Many organellar RBPs have been functionally assigned to individual steps in RNA maturation, often specific to selected transcripts. While the catalog of factors identified is ever-growing, our knowledge of how they achieve their functions mechanistically is far from complete. This review summarizes the current knowledge of plant organellar RNA metabolism taking an RBP-centric approach and focusing on mechanistic aspects of RBP functions and the kinetics of the processes they are involved in.
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Affiliation(s)
- Ian Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley 6009, Australia
| | - Joanna Melonek
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley 6009, Australia
| | | | - Jörg Nickelsen
- Department of Molecular Plant Sciences, LMU Munich, 82152 Martinsried, Germany
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12
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McCray TN, Azim MF, Burch-Smith TM. The dicot homolog of maize PPR103 carries a C-terminal DYW domain and is required for C-to-U editing of chloroplast RNA transcripts. RESEARCH SQUARE 2023:rs.3.rs-2574001. [PMID: 36865278 PMCID: PMC9980218 DOI: 10.21203/rs.3.rs-2574001/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
In plants, cytidine-to-uridine (C-to-U) editing is a crucial step in processing mitochondria and chloroplast-encoded transcripts. This editing requires nuclear-encoded proteins including members of the pentatricopeptide (PPR) family, especially PLS-type proteins carrying the DYW domain. IPI1/emb175/PPR103 is a nuclear gene encoding a PLS-type PPR protein essential for survival in Arabidopsis thaliana and maize. Arabidopsis IPI1 was identified as likely interacting with ISE2, a chloroplast-localized RNA helicase associated with C-to-U RNA editing in Arabidopsis and maize. Notably, while the Arabidopsis and Nicotiana IPI1 homologs possess complete DYW motifs at their C-termini, the maize homolog, ZmPPR103, lacks this triplet of residues which are essential for editing. We examined the function of ISE2 and IPI1 in chloroplast RNA processing in N. benthamiana. A combination of deep sequencing and Sanger sequencing revealed C-to-U editing at 41 sites in 18 transcripts, with 34 sites conserved in the closely related N. tabacum. Virus induced gene silencing of NbISE2 or NbIPI1 led to defective C-to-U revealed that they have overlapping roles at editing a site in the rpoB transcript but have distinct roles in editing other transcripts. This finding contrasts with maize ppr103 mutants that showed no defects in editing. The results indicate that NbISE2 and NbIPI1 are important for C-to-U editing in N. benthamiana chloroplasts, and they may function in a complex to edit specific sites while having antagonistic effects on editing others. That NbIPI1, carrying a DYW domain, is involved in organelle C-to-U RNA editing supports previous work showing that this domain catalyzes RNA editing.
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Affiliation(s)
- Tyra N. McCray
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - Mohammad F. Azim
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN 37996
- Donald Danforth Plant Science Center, St. Louis, MO 63132
| | - Tessa M. Burch-Smith
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN 37996
- Donald Danforth Plant Science Center, St. Louis, MO 63132
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13
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Ershova N, Sheshukova E, Kamarova K, Arifulin E, Tashlitsky V, Serebryakova M, Komarova T. Nicotiana benthamiana Kunitz peptidase inhibitor-like protein involved in chloroplast-to-nucleus regulatory pathway in plant-virus interaction. FRONTIERS IN PLANT SCIENCE 2022; 13:1041867. [PMID: 36438111 PMCID: PMC9685412 DOI: 10.3389/fpls.2022.1041867] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
Plant viruses use a variety of strategies to infect their host. During infection, viruses cause symptoms of varying severity, which are often associated with altered leaf pigmentation due to structural and functional damage to chloroplasts that are affected by viral proteins. Here we demonstrate that Nicotiana benthamiana Kunitz peptidase inhibitor-like protein (KPILP) gene is induced in response to potato virus X (PVX) infection. Using reverse genetic approach, we have demonstrated that KPILP downregulates expression of LHCB1 and LHCB2 genes of antenna light-harvesting complex proteins, HEMA1 gene encoding glutamyl-tRNA reductase, which participates in tetrapyrrole biosynthesis, and RBCS1A gene encoding RuBisCO small subunit isoform involved in the antiviral immune response. Thus, KPILP is a regulator of chloroplast retrograde signaling system during developing PVX infection. Moreover, KPILP was demonstrated to affect carbon partitioning: reduced glucose levels during PVX infection were associated with KPILP upregulation. Another KPILP function is associated with plasmodesmata permeability control. Its ability to stimulate intercellular transport of reporter 2xGFP molecules indicates that KPILP is a positive plasmodesmata regulator. Moreover, natural KPILP glycosylation is indispensable for manifestation of this function. During PVX infection KPILP increased expression leads to the reduction of plasmodesmata callose deposition. These results could indicate that KPILP affects plasmodesmata permeability via callose-dependent mechanism. Thus, virus entering a cell and starting reproduction triggers KPILP expression, which leads to downregulation of nuclear-encoded chloroplast genes associated with retrograde signaling, reduction in photoassimilates accumulation and increase in intercellular transport, creating favorable conditions for reproduction and spread of viral infection.
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Affiliation(s)
- Natalia Ershova
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Ekaterina Sheshukova
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Kamila Kamarova
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Evgenii Arifulin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Vadim Tashlitsky
- Chemistry Department, Lomonosov Moscow State University, Moscow, Russia
| | - Marina Serebryakova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Tatiana Komarova
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
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14
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Robles P, Quesada V. Unveiling the functions of plastid ribosomal proteins in plant development and abiotic stress tolerance. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 189:35-45. [PMID: 36041366 DOI: 10.1016/j.plaphy.2022.07.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/22/2022] [Accepted: 07/24/2022] [Indexed: 06/15/2023]
Abstract
Translation of mRNAs into proteins is a universal process and ribosomes are the molecular machinery that carries it out. In eukaryotic cells, ribosomes can be found in the cytoplasm, mitochondria, and also in the chloroplasts of photosynthetic organisms. A number of genetic studies have been performed to determine the function of plastid ribosomal proteins (PRPs). Tobacco has been frequently used as a system to study the ribosomal proteins encoded by the chloroplast genome. In contrast, Arabidopsis thaliana and rice are preferentially used models to study the function of nuclear-encoded PRPs by using direct or reverse genetics approaches. The results of these works have provided a relatively comprehensive catalogue of the roles of PRPs in different plant biology aspects, which highlight that some PRPs are essential, while others are not. The latter ones are involved in chloroplast biogenesis, lateral root formation, leaf morphogenesis, plant growth, photosynthesis or chlorophyll synthesis. Furthermore, small gene families encode some PRPs. In the last few years, an increasing number of findings have revealed a close association between PRPs and tolerance to adverse environmental conditions. Sometimes, the same PRP can be involved in both developmental processes and the response to abiotic stress. The aim of this review is to compile and update the findings hitherto published on the functional analysis of PRPs. The study of the phenotypic effects caused by the disruption of PRPs from different species reveals the involvement of PRPs in different biological processes and highlights the significant impact of plastid translation on plant biology.
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Affiliation(s)
- Pedro Robles
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain
| | - Víctor Quesada
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain.
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15
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Zeng C, Jiao Q, Jia T, Hu X. Updated Progress on Group II Intron Splicing Factors in Plant Chloroplasts. Curr Issues Mol Biol 2022; 44:4229-4239. [PMID: 36135202 PMCID: PMC9497791 DOI: 10.3390/cimb44090290] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/05/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
Group II introns are large catalytic RNAs (ribozymes) in the bacteria and organelle genomes of several lower eukaryotes. Many critical photosynthesis-related genes in the plant chloroplast genome also contain group II introns, and their splicing is critical for chloroplast biogenesis and photosynthesis processes. The structure of chloroplast group II introns was altered during evolution, resulting in the loss of intron self-splicing. Therefore, the assistance of protein factors was required for their splicing processes. As an increasing number of studies focus on the mechanism of chloroplast intron splicing; many new nuclear-encoded splicing factors that are involved in the chloroplast intron splicing process have been reported. This report reviewed the research progress of the updated splicing factors found to be involved in the splicing of chloroplast group II introns. We discuss the main problems that remain in this research field and suggest future research directions.
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Affiliation(s)
- Chu Zeng
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology/Jiangsu Provincial Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
- Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Qingsong Jiao
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology/Jiangsu Provincial Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
- Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Ting Jia
- Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Xueyun Hu
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology/Jiangsu Provincial Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
- Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
- Correspondence:
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16
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Maeda A, Takenaka S, Wang T, Frink B, Shikanai T, Takenaka M. DYW deaminase domain has a distinct preference for neighboring nucleotides of the target RNA editing sites. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:756-767. [PMID: 35652245 DOI: 10.1111/tpj.15850] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 05/21/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
C-to-U RNA editing sites in plant organelles show a strong bias for neighboring nucleotides. The nucleotide upstream of the target cytidine is typically C or U, whereas A and G are less common and rare, respectively. In pentatricopeptide repeat (PPR)-type RNA editing factors, the PPR domain specifically binds to the 5' sequence of target cytidines, whereas the DYW domain catalyzes the C-to-U deamination. We comprehensively analyzed the effects of neighboring nucleotides of the target cytidines using an Escherichia coli orthogonal system. Physcomitrium PPR56 efficiently edited target cytidines when the nucleotide upstream was U or C, whereas it barely edited when the position was G or the nucleotide downstream was C. This preference pattern, which corresponds well with the observed nucleotide bias for neighboring nucleotides in plant organelles, was altered when the DYW domain of OTP86 or DYW1 was adopted. The PPR56 chimeric proteins edited the target sites even when the -1 position was G. Our results suggest that the DYW domain possesses a distinct preference for the neighboring nucleotides of the target sites, thus contributing to target selection in addition to the existing selection determined by the PPR domain.
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Affiliation(s)
- Ayako Maeda
- Department of Botany Graduate School of Science, Kyoto University, Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Sachi Takenaka
- Department of Botany Graduate School of Science, Kyoto University, Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Tenghua Wang
- Department of Botany Graduate School of Science, Kyoto University, Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Brody Frink
- Department of Botany Graduate School of Science, Kyoto University, Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Toshiharu Shikanai
- Department of Botany Graduate School of Science, Kyoto University, Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Mizuki Takenaka
- Department of Botany Graduate School of Science, Kyoto University, Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
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17
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Carlotto N, Robles-Luna G, Nedo A, Wang X, Attorresi A, Caplan J, Lee JY, Kobayashi K. Evidence for reduced plasmodesmata callose accumulation in Nicotiana benthamiana leaves with increased symplastic cell-to-cell communication caused by RNA processing defects of chloroplasts. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 179:58-64. [PMID: 35313145 DOI: 10.1016/j.plaphy.2022.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/09/2022] [Accepted: 03/09/2022] [Indexed: 06/14/2023]
Abstract
RNA processing defects in chloroplasts were previously associated with increased plasmodesmata (PD) permeability. However, the underlying mechanisms for such association are still unknown. To provide insight into this, we silenced the expression of chloroplast-located INCREASED SIZE EXCLUSION LIMIT 2 (ISE2) RNA helicase in Nicotiana benthamiana leaves and determined an increase in PD permeability which is caused by a reduction of PD callose deposition. Moreover, the silencing of two other nuclear genes encoding chloroplastic enzymes involved in RNA processing, RH3, and CLPR2, also increased PD permeability accompanied by reduced callose accumulation at PD. In addition, we quantified the plastidic hydrogen peroxide levels using the chloroplast-targeted fluorescent sensor, HyPer, in ISE2, RH3, and CLPR2 silenced N. benthamiana leaves. The levels of chloroplastic hydrogen peroxide were not correlated with the increased cell-to-cell movement of the marker protein GFP2X. We, therefore, propose that defects in chloroplast RNA metabolism mediate PD gating by suppressing PD callose deposition, and hydrogen peroxide levels in the organelles are not directly linked to this process.
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Affiliation(s)
- Nicolas Carlotto
- Laboratorio de Agrobiotecnología, Departamento de Fisiología y Biología Molecular y Celular - Instituto de Biodiversidad y Biología Experimental Aplicada, FCEN UBA - CONICET, Ciudad Autónoma de Buenos Aires, C1428, EGA, Argentina
| | - Gabriel Robles-Luna
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, 19711, USA
| | - Alexander Nedo
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, 19711, USA
| | - Xu Wang
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, 19711, USA; Department of Plant Physiology and Biochemistry, Institute of Biology, University of Hohenheim, Stuttgart, 70593, Germany
| | - Alejandra Attorresi
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) -CONICET- Partner Institute of the Max Planck Society, Ciudad Autónoma de Buenos Aires, C1425, FQD, Argentina
| | - Jeffrey Caplan
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, 19711, USA
| | - Jung Y Lee
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, 19711, USA
| | - Ken Kobayashi
- Laboratorio de Agrobiotecnología, Departamento de Fisiología y Biología Molecular y Celular - Instituto de Biodiversidad y Biología Experimental Aplicada, FCEN UBA - CONICET, Ciudad Autónoma de Buenos Aires, C1428, EGA, Argentina.
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18
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Yang D, Cao SK, Yang H, Liu R, Sun F, Wang L, Wang M, Tan BC. DEK48 Is Required for RNA Editing at Multiple Mitochondrial Sites and Seed Development in Maize. Int J Mol Sci 2022; 23:ijms23063064. [PMID: 35328485 PMCID: PMC8952262 DOI: 10.3390/ijms23063064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 11/26/2022] Open
Abstract
In flowering plants, C-to-U RNA editing can be critical to normal functions of mitochondrion-encoded proteins. Mitochondrial C-to-U RNA editing is facilitated by many factors from diverse protein families, of which the pentatricopeptide repeat (PPR) proteins play an important role. Owing to their large number and frequent embryo lethality in mutants, functions of many PPRs remain unknown. In this study, we characterized a mitochondrion-localized DYW-type PPR protein, DEK48, functioning in the C-to-U RNA editing at multiple mitochondrial transcripts in maize. Null mutation of Dek48 severely arrests embryo and endosperm development, causing a defective kernel (dek) phenotype, named dek48. DEK48 loss of function abolishes the C-to-U editing at nad3-185, -215, and nad4-376, -977 sites and decreases the editing at 11 other sites, resulting in the alteration of the corresponding amino acids. Consequently, the absence of editing caused reduced assembly and activity of complex I in dek48. Interestingly, we identified a point mutation in dek48-3 causing a deletion of the Tryptophan (W) residue in the DYW motif that abolishes the editing function. In sum, this study reveals the function of DEK48 in the C-to-U editing in mitochondrial transcripts and seed development in maize, and it demonstrates a critical role of the W residue in the DYW triplet motif of DEK48 for the C-to-U editing function in vivo.
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19
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Zhang L, Chen J, Zhang L, Wei Y, Li Y, Xu X, Wu H, Yang ZN, Huang J, Hu F, Huang W, Cui YL. The pentatricopeptide repeat protein EMB1270 interacts with CFM2 to splice specific group II introns in Arabidopsis chloroplasts. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2021; 63:1952-1966. [PMID: 34427970 DOI: 10.1111/jipb.13165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Chloroplast biogenesis requires the coordinated expression of chloroplast and nuclear genes. Here, we show that EMB1270, a plastid-localized pentatricopeptide repeat (PPR) protein, is required for chloroplast biogenesis in Arabidopsis thaliana. Knockout of EMB1270 led to embryo arrest, whereas a mild knockdown mutant of EMB1270 displayed a virescent phenotype. Almost no photosynthetic proteins accumulated in the albino emb1270 knockout mutant. By contrast, in the emb1270 knockdown mutant, the levels of ClpP1 and photosystem I (PSI) subunits were significantly reduced, whereas the levels of photosystem II (PSII) subunits were normal. Furthermore, the splicing efficiencies of the clpP1.2, ycf3.1, ndhA, and ndhB plastid introns were dramatically reduced in both emb1270 mutants. RNA immunoprecipitation revealed that EMB1270 associated with these introns in vivo. In an RNA electrophoretic mobility shift assay (REMSA), a truncated EMB1270 protein containing the 11 N-terminal PPR motifs bound to the predicted sequences of the clpP1.2, ycf3.1, and ndhA introns. In addition, EMB1270 specifically interacted with CRM Family Member 2 (CFM2). Given that CFM2 is known to be required for splicing the same plastid RNAs, our results suggest that EMB1270 associates with CFM2 to facilitate the splicing of specific group II introns in Arabidopsis.
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Affiliation(s)
- Li Zhang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Jingli Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Liqun Zhang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Ying Wei
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Yajuan Li
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Xinyun Xu
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Hui Wu
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Zhong-Nan Yang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Jirong Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Fenhong Hu
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Weihua Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Yong-Lan Cui
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
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20
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Mukhopadhyay J, Hausner G. Organellar Introns in Fungi, Algae, and Plants. Cells 2021; 10:cells10082001. [PMID: 34440770 PMCID: PMC8393795 DOI: 10.3390/cells10082001] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/31/2021] [Accepted: 08/05/2021] [Indexed: 12/16/2022] Open
Abstract
Introns are ubiquitous in eukaryotic genomes and have long been considered as ‘junk RNA’ but the huge energy expenditure in their transcription, removal, and degradation indicate that they may have functional significance and can offer evolutionary advantages. In fungi, plants and algae introns make a significant contribution to the size of the organellar genomes. Organellar introns are classified as catalytic self-splicing introns that can be categorized as either Group I or Group II introns. There are some biases, with Group I introns being more frequently encountered in fungal mitochondrial genomes, whereas among plants Group II introns dominate within the mitochondrial and chloroplast genomes. Organellar introns can encode a variety of proteins, such as maturases, homing endonucleases, reverse transcriptases, and, in some cases, ribosomal proteins, along with other novel open reading frames. Although organellar introns are viewed to be ribozymes, they do interact with various intron- or nuclear genome-encoded protein factors that assist in the intron RNA to fold into competent splicing structures, or facilitate the turn-over of intron RNAs to prevent reverse splicing. Organellar introns are also known to be involved in non-canonical splicing, such as backsplicing and trans-splicing which can result in novel splicing products or, in some instances, compensate for the fragmentation of genes by recombination events. In organellar genomes, Group I and II introns may exist in nested intronic arrangements, such as introns within introns, referred to as twintrons, where splicing of the external intron may be dependent on splicing of the internal intron. These nested or complex introns, with two or three-component intron modules, are being explored as platforms for alternative splicing and their possible function as molecular switches for modulating gene expression which could be potentially applied towards heterologous gene expression. This review explores recent findings on organellar Group I and II introns, focusing on splicing and mobility mechanisms aided by associated intron/nuclear encoded proteins and their potential roles in organellar gene expression and cross talk between nuclear and organellar genomes. Potential application for these types of elements in biotechnology are also discussed.
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MESH Headings
- Evolution, Molecular
- Gene Expression Regulation, Fungal
- Gene Expression Regulation, Plant
- Genome, Fungal
- Genome, Plant
- Introns
- Organelles/genetics
- Organelles/metabolism
- RNA Splicing
- RNA Stability
- RNA, Algal/genetics
- RNA, Algal/metabolism
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- RNA, Untranslated/genetics
- RNA, Untranslated/metabolism
- Transcription, Genetic
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21
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Méteignier LV, Ghandour R, Zimmerman A, Kuhn L, Meurer J, Zoschke R, Hammani K. Arabidopsis mTERF9 protein promotes chloroplast ribosomal assembly and translation by establishing ribonucleoprotein interactions in vivo. Nucleic Acids Res 2021; 49:1114-1132. [PMID: 33398331 PMCID: PMC7826268 DOI: 10.1093/nar/gkaa1244] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/07/2020] [Accepted: 12/13/2020] [Indexed: 12/13/2022] Open
Abstract
The mitochondrial transcription termination factor proteins are nuclear-encoded nucleic acid binders defined by degenerate tandem helical-repeats of ∼30 amino acids. They are found in metazoans and plants where they localize in organelles. In higher plants, the mTERF family comprises ∼30 members and several of these have been linked to plant development and response to abiotic stress. However, knowledge of the molecular basis underlying these physiological effects is scarce. We show that the Arabidopsis mTERF9 protein promotes the accumulation of the 16S and 23S rRNAs in chloroplasts, and interacts predominantly with the 16S rRNA in vivo and in vitro. Furthermore, mTERF9 is found in large complexes containing ribosomes and polysomes in chloroplasts. The comprehensive analysis of mTERF9 in vivo protein interactome identified many subunits of the 70S ribosome whose assembly is compromised in the null mterf9 mutant, putative ribosome biogenesis factors and CPN60 chaperonins. Protein interaction assays in yeast revealed that mTERF9 directly interact with these proteins. Our data demonstrate that mTERF9 integrates protein-protein and protein-RNA interactions to promote chloroplast ribosomal assembly and translation. Besides extending our knowledge of mTERF functional repertoire in plants, these findings provide an important insight into the chloroplast ribosome biogenesis.
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Affiliation(s)
- Louis-Valentin Méteignier
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France
| | - Rabea Ghandour
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Aude Zimmerman
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France
| | - Lauriane Kuhn
- Plateforme protéomique Strasbourg Esplanade FRC1589 du CNRS, Université de Strasbourg, 15 rue René Descartes, 67084 Strasbourg, France
| | - Jörg Meurer
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Street 2-4, 82152 Planegg-Martinsried, Germany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Kamel Hammani
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France
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22
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Dai D, Ma Z, Song R. Maize kernel development. MOLECULAR BREEDING : NEW STRATEGIES IN PLANT IMPROVEMENT 2021; 41:2. [PMID: 37309525 PMCID: PMC10231577 DOI: 10.1007/s11032-020-01195-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/03/2020] [Indexed: 06/14/2023]
Abstract
Maize (Zea mays) is a leading cereal crop in the world. The maize kernel is the storage organ and the harvest portion of this crop and is closely related to its yield and quality. The development of maize kernel is initiated by the double fertilization event, leading to the formation of a diploid embryo and a triploid endosperm. The embryo and endosperm are then undergone independent developmental programs, resulting in a mature maize kernel which is comprised of a persistent endosperm, a large embryo, and a maternal pericarp. Due to the well-characterized morphogenesis and powerful genetics, maize kernel has long been an excellent model for the study of cereal kernel development. In recent years, with the release of the maize reference genome and the development of new genomic technologies, there has been an explosive expansion of new knowledge for maize kernel development. In this review, we overviewed recent progress in the study of maize kernel development, with an emphasis on genetic mapping of kernel traits, transcriptome analysis during kernel development, functional gene cloning of kernel mutants, and genetic engineering of kernel traits.
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Affiliation(s)
- Dawei Dai
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Beijing Key Laboratory of Crop Genetic Improvement, Joint International Research Laboratory of Crop Molecular Breeding, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193 China
- Shanghai Key Laboratory of Bio-Energy Crops, Plant Science Center, School of Life Sciences, Shanghai University, Shanghai, 200444 China
| | - Zeyang Ma
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Beijing Key Laboratory of Crop Genetic Improvement, Joint International Research Laboratory of Crop Molecular Breeding, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193 China
| | - Rentao Song
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Beijing Key Laboratory of Crop Genetic Improvement, Joint International Research Laboratory of Crop Molecular Breeding, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193 China
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23
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Azim MF, Burch-Smith TM. Organelles-nucleus-plasmodesmata signaling (ONPS): an update on its roles in plant physiology, metabolism and stress responses. CURRENT OPINION IN PLANT BIOLOGY 2020; 58:48-59. [PMID: 33197746 DOI: 10.1016/j.pbi.2020.09.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/26/2020] [Accepted: 09/27/2020] [Indexed: 05/03/2023]
Abstract
Plasmodesmata allow movement of metabolites and signaling molecules between plant cells and are, therefore, critical players in plant development and physiology, and in responding to environmental signals and stresses. There is emerging evidence that plasmodesmata are controlled by signaling originating from other organelles, primarily the chloroplasts and mitochondria. These signals act in the nucleus to alter expression of genetic pathways that control both trafficking via plasmodesmata and the plasmodesmatal pores themselves. This control circuit was dubbed organelle-nucleus-plasmodesmata signaling (ONPS). Here we discuss how ONPS arose during plant evolution and highlight the discovery of an ONPS-like module for regulating stomata. We also consider recent findings that illuminate details of the ONPS circuit and its roles in plant physiology, metabolism, and defense.
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Affiliation(s)
- Mohammad F Azim
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tessa M Burch-Smith
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States.
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24
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Liu R, Cao SK, Sayyed A, Xu C, Sun F, Wang X, Tan BC. The Mitochondrial Pentatricopeptide Repeat Protein PPR18 Is Required for the cis-Splicing of nad4 Intron 1 and Essential to Seed Development in Maize. Int J Mol Sci 2020; 21:ijms21114047. [PMID: 32516991 PMCID: PMC7312232 DOI: 10.3390/ijms21114047] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 05/30/2020] [Accepted: 06/02/2020] [Indexed: 11/16/2022] Open
Abstract
Pentatricopeptide repeat (PPR) protein comprises a large family, participating in various aspects of organellar RNA metabolism in land plants. There are approximately 600 PPR proteins in maize, but the functions of many PPR proteins remain unknown. In this study, we defined the function of PPR18 in the cis-splicing of nad4 intron 1 in mitochondria and seed development in maize. Loss function of PPR18 seriously impairs embryo and endosperm development, resulting in the empty pericarp (emp) phenotype in maize. PPR18 encodes a mitochondrion-targeted P-type PPR protein with 18 PPR motifs. Transcripts analysis indicated that the splicing of nad4 intron 1 is impaired in the ppr18 mutant, resulting in the absence of nad4 transcript, leading to severely reduced assembly and activity of mitochondrial complex I and dramatically reduced respiration rate. These results demonstrate that PPR18 is required for the cis-splicing of nad4 intron 1 in mitochondria, and critical to complex I assembly and seed development in maize.
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Affiliation(s)
- Rui Liu
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (R.L.); (S.-K.C.); (A.S.); (C.X.); (F.S.)
| | - Shi-Kai Cao
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (R.L.); (S.-K.C.); (A.S.); (C.X.); (F.S.)
| | - Aqib Sayyed
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (R.L.); (S.-K.C.); (A.S.); (C.X.); (F.S.)
| | - Chunhui Xu
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (R.L.); (S.-K.C.); (A.S.); (C.X.); (F.S.)
| | - Feng Sun
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (R.L.); (S.-K.C.); (A.S.); (C.X.); (F.S.)
| | - Xiaomin Wang
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, China;
| | - Bao-Cai Tan
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (R.L.); (S.-K.C.); (A.S.); (C.X.); (F.S.)
- Correspondence:
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25
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Wang HC, Sayyed A, Liu XY, Yang YZ, Sun F, Wang Y, Wang M, Tan BC. SMALL KERNEL4 is required for mitochondrial cox1 transcript editing and seed development in maize. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2020; 62:777-792. [PMID: 31332949 DOI: 10.1111/jipb.12856] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
In land plants, cytidine-to-uridine (C-to-U) editing of organellar transcripts is an important post-transcriptional process, which is considered to remediate DNA genetic mutations to restore the coding of functional proteins. Pentatricopeptide repeat (PPR) proteins have key roles in C-to-U editing. Owing to its large number, however, the biological functions of many PPR proteins remain to be identified. Through characterizing a small kernel4 (smk4) mutant, here we report the function of Smk4 and its role in maize growth and development. Null mutation of Smk4 slows plant growth and development, causing small plants, delayed flowering time, and small kernels. Cloning revealed that Smk4 encodes a new E-subclass PPR protein, and localization indicated that SMK4 is exclusively localized in mitochondria. Loss of Smk4 function abolishes C-to-U editing at position 1489 of the cytochrome c oxidase1 (cox1) transcript, causing an amino acid change from serine to proline at 497 in Cox1. Cox1 is a core component of mitochondrial complex IV. Indeed, complex IV activity is reduced in the smk4, along with drastically elevated expression of alternative oxidases (AOX). These results indicate that SMK4 functions in the C-to-U editing of cox1-1489, and this editing is crucial for mitochondrial complex IV activity, plant growth, and kernel development in maize.
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Affiliation(s)
- Hong-Chun Wang
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Aqib Sayyed
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Xin-Yuan Liu
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Yan-Zhuo Yang
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Feng Sun
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Yong Wang
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Miaodi Wang
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Bao-Cai Tan
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
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26
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Ganusova EE, Reagan BC, Fernandez JC, Azim MF, Sankoh AF, Freeman KM, McCray TN, Patterson K, Kim C, Burch-Smith TM. Chloroplast-to-nucleus retrograde signalling controls intercellular trafficking via plasmodesmata formation. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190408. [PMID: 32362251 DOI: 10.1098/rstb.2019.0408] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The signalling pathways that regulate intercellular trafficking via plasmodesmata (PD) remain largely unknown. Analyses of mutants with defects in intercellular trafficking led to the hypothesis that chloroplasts are important for controlling PD, probably by retrograde signalling to the nucleus to regulate expression of genes that influence PD formation and function, an idea encapsulated in the organelle-nucleus-PD signalling (ONPS) hypothesis. ONPS is supported by findings that point to chloroplast redox state as also modulating PD. Here, we have attempted to further elucidate details of ONPS. Through reverse genetics, expression of select nucleus-encoded genes with known or predicted roles in chloroplast gene expression was knocked down, and the effects on intercellular trafficking were then assessed. Silencing most genes resulted in chlorosis, and the expression of several photosynthesis and tetrapyrrole biosynthesis associated nuclear genes was repressed in all silenced plants. PD-mediated intercellular trafficking was changed in the silenced plants, consistent with predictions of the ONPS hypothesis. One striking observation, best exemplified by silencing the PNPase homologues, was that the degree of chlorosis of silenced leaves was not correlated with the capacity for intercellular trafficking. Finally, we measured the distribution of PD in silenced leaves and found that intercellular trafficking was positively correlated with the numbers of PD. Together, these results not only provide further support for ONPS but also point to a genetic mechanism for PD formation, clarifying a longstanding question about PD and intercellular trafficking. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.
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Affiliation(s)
- Elena E Ganusova
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Brandon C Reagan
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Jessica C Fernandez
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Mohammad F Azim
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Amie F Sankoh
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | | | - Tyra N McCray
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Kelsey Patterson
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Chinkee Kim
- Departments of Science and Mathematics, RIT/National Technical Institute for the Deaf (NTID), Rochester, NY 14623, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
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27
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Zhao X, Huang J, Chory J. Unraveling the Linkage between Retrograde Signaling and RNA Metabolism in Plants. TRENDS IN PLANT SCIENCE 2020; 25:141-147. [PMID: 31791654 DOI: 10.1016/j.tplants.2019.10.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/09/2019] [Accepted: 10/23/2019] [Indexed: 05/25/2023]
Abstract
Retrograde signals are signals that originate in organelles to regulate nuclear gene expression. In plant cells, retrograde signaling from both chloroplasts and mitochondria is essential for plant development and growth. Over the past few years, substantial progress has been made in unraveling the linkages between chloroplast retrograde signaling and nuclear RNA metabolism processes or plastidial RNA editing. These findings add to the complexity of the regulation of organelle-to-nucleus communication. Chloroplast development and function rely on the coordinated regulation of chloroplast and nuclear gene expression, especially under stress conditions. A better understanding of retrograde signaling and RNA metabolism, as well as their connection, is essential for breeding stress-tolerant plants to cope with the dynamic and rapidly changing environment.
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Affiliation(s)
- Xiaobo Zhao
- Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China; Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
| | - Jianyan Huang
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Joanne Chory
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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28
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Hayes ML, Santibanez PI. A plant pentatricopeptide repeat protein with a DYW-deaminase domain is sufficient for catalyzing C-to-U RNA editing in vitro. J Biol Chem 2020; 295:3497-3505. [PMID: 31996373 DOI: 10.1074/jbc.ra119.011790] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 01/23/2020] [Indexed: 12/27/2022] Open
Abstract
Pentatricopeptide repeat (PPR) proteins with C-terminal DYW domains are present in organisms that undergo C-to-U editing of organelle RNA transcripts. PPR domains act as specificity factors through electrostatic interactions between a pair of polar residues and the nitrogenous bases of an RNA target. DYW-deaminase domains act as the editing enzyme. Two moss (Physcomitrella patens) PPR proteins containing DYW-deaminase domains, PPR65 and PPR56, can convert Cs to Us in cognate, exogenous RNA targets co-expressed in Escherichia coli We show here that purified, recombinant PPR65 exhibits robust editase activity on synthetic RNAs containing cognate, mitochondrial PpccmFC sequences in vitro, indicating that a PPR protein with a DYW domain is solely sufficient for catalyzing C-to-U RNA editing in vitro Monomeric fractions possessed the highest conversion efficiency, and oligomeric fractions had reduced activity. Inductively coupled plasma (ICP)-MS analysis indicated a stoichiometry of two zinc ions per highly active PPR65 monomer. Editing activity was sensitive to addition of zinc acetate or the zinc chelators 1,10-o-phenanthroline and EDTA. Addition of ATP or nonhydrolyzable nucleotide analogs stimulated PPR65-catalyzed RNA-editing activity on PpccmFC substrates, indicating potential allosteric regulation of PPR65 by ATP. Unlike for bacterial cytidine deaminase, addition of two putative transition-state analogs, zebularine and tetrahydrouridine, failed to disrupt RNA-editing activity. RNA oligonucleotides with a single incorporated zebularine also did not disrupt editing in vitro, suggesting that PPR65 cannot bind modified bases due to differences in the structure of the active site compared with other zinc-dependent nucleotide deaminases.
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Affiliation(s)
- Michael L Hayes
- Department of Chemistry and Biochemistry, California State University Los Angeles, Los Angeles, California 90032.
| | - Paola I Santibanez
- Department of Chemistry and Biochemistry, California State University Los Angeles, Los Angeles, California 90032
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29
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Reagan BC, Burch-Smith TM. Viruses Reveal the Secrets of Plasmodesmal Cell Biology. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:26-39. [PMID: 31715107 DOI: 10.1094/mpmi-07-19-0212-fi] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Plasmodesmata (PD) are essential for intercellular trafficking of molecules required for plant life, from small molecules like sugars and ions to macromolecules including proteins and RNA molecules that act as signals to regulate plant development and defense. As obligate intracellular pathogens, plant viruses have evolved to manipulate this communication system to facilitate the initial cell-to-cell and eventual systemic spread in their plant hosts. There has been considerable interest in how viruses manipulate the PD that connect the protoplasts of neighboring cells, and viruses have yielded invaluable tools for probing the structure and function of PD. With recent advances in biochemistry and imaging, we have gained new insights into the composition and structure of PD in the presence and absence of viruses. Here, we first discuss viral strategies for manipulating PD for their intercellular movement and examine how this has shed light on our understanding of native PD function. We then address the controversial role of the cytoskeleton in trafficking to and through PD. Finally, we address how viruses could alter PD structure and consider possible mechanisms of the phenomenon described as 'gating'. This discussion supports the significance of virus research in elucidating the properties of PD, these persistently enigmatic plant organelles.
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Affiliation(s)
- Brandon C Reagan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, U.S.A
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, U.S.A
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30
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Wang X, Zhao L, Man Y, Li X, Wang L, Xiao J. PDM4, a Pentatricopeptide Repeat Protein, Affects Chloroplast Gene Expression and Chloroplast Development in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2020; 11:1198. [PMID: 32849743 PMCID: PMC7432182 DOI: 10.3389/fpls.2020.01198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 07/23/2020] [Indexed: 05/10/2023]
Abstract
Extensive studies have been carried out on chloroplast gene expression and chloroplast development; however, the regulatory mechanism is still largely unknown. Here, we characterized Pigment-Defective Mutant4 (PDM4), a P-type PPR protein localized in chloroplast. The pdm4 mutant showed seedling-lethal and albino phenotype under heterotrophic growth conditions. Transmission electron microscopic analysis revealed that thylakoid structure was totally disrupted in pdm4 mutant and eventually led to the breakdown of chloroplasts. The levels of several chloroplast- and nuclear-encoded proteins are strongly reduced in pdm4 mutant. Besides, transcript profile analysis detected that, in pdm4 mutant, the expression of plastid-encoded RNA polymerase-dependent genes was markedly affected, and deviant chloroplast rRNA processing was also observed. In addition, we found that PDM4 functions in the splicing of group II introns and may also be involved in the assembly of the 50S ribosomal particle. Our results demonstrate that PDM4 plays an important role in chloroplast gene expression and chloroplast development in Arabidopsis.
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Affiliation(s)
- Xinwei Wang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Lirong Zhao
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Yi Man
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Xiaojuan Li
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Li Wang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Jianwei Xiao
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
- *Correspondence: Jianwei Xiao,
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31
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MORF9 Functions in Plastid RNA Editing with Tissue Specificity. Int J Mol Sci 2019; 20:ijms20184635. [PMID: 31546885 PMCID: PMC6769653 DOI: 10.3390/ijms20184635] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/11/2019] [Accepted: 09/13/2019] [Indexed: 11/17/2022] Open
Abstract
RNA editing in plant mitochondria and plastids converts specific nucleotides from cytidine (C) to uridine (U). These editing events differ among plant species and are relevant to developmental stages or are impacted by environmental conditions. Proteins of the MORF family are essential components of plant editosomes. One of the members, MORF9, is considered the core protein of the editing complex and is involved in the editing of most sites in chloroplasts. In this study, the phenotypes of a T-DNA insertion line with loss of MORF9 and of the genetic complementation line of Arabidopsis were analyzed, and the editing efficiencies of plastid RNAs in roots, rosette leaves, and flowers from the morf9 mutant and the wild-type (WT) control were compared by bulk-cDNA sequencing. The results showed that most of the known MORF9-associated plastid RNA editing events in rosette leaves and flowers were similarly reduced by morf9 mutation, with the exception that the editing rate of the sites ndhB-872 and psbF-65 declined in the leaves and that of ndhB-586 decreased only in the flowers. In the roots, however, the loss of MORF9 had a much lower effect on overall plastid RNA editing, with nine sites showing no significant editing efficiency change, including accD-794, ndhD-383, psbZ-50, ndhF-290, ndhD-878, matK-706, clpP1-559, rpoA-200, and ndhD-674, which were reduced in the other tissues. Furthermore, we found that during plant aging, MORF9 mRNA level, but not the protein level, was downregulated in senescent leaves. On the basis of these observations, we suggest that MORF9-mediated RNA editing is tissue-dependent and the resultant organelle proteomes are pertinent to the specific tissue functions.
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Sandoval R, Boyd RD, Kiszter AN, Mirzakhanyan Y, Santibańez P, Gershon PD, Hayes ML. Stable native RIP9 complexes associate with C-to-U RNA editing activity, PPRs, RIPs, OZ1, ORRM1 and ISE2. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 99:1116-1126. [PMID: 31077462 PMCID: PMC6744336 DOI: 10.1111/tpj.14384] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/23/2019] [Accepted: 04/30/2019] [Indexed: 05/02/2023]
Abstract
The mitochondrial and chloroplast mRNAs of the majority of land plants are modified through cytidine to uridine (C-to-U) RNA editing. Previously, forward and reverse genetic screens demonstrated a requirement for pentatricopeptide repeat (PPR) proteins for RNA editing. Moreover, chloroplast editing factors OZ1, RIP2, RIP9 and ORRM1 were identified in co-immunoprecipitation (co-IP) experiments, albeit the minimal complex sufficient for editing activity was never deduced. The current study focuses on isolated, intact complexes that are capable of editing distinct sites. Peak editing activity for four sites was discovered in size-exclusion chromatography (SEC) fractions ≥ 670 kDa, while fractions estimated to be approximately 413 kDa exhibited the greatest ability to convert a substrate containing the editing site rps14 C80. RNA content peaked in the ≥ 670 kDa fraction. Treatment of active chloroplast extracts with RNase A abolished the relationship of editing activity with high-MW fractions, suggesting a structural RNA component in native complexes. By immunoblotting, RIP9, OTP86, OZ1 and ORRM1 were shown to be present in active gel filtration fractions, though OZ1 and ORRM1 were mainly found in low-MW inactive fractions. Active editing factor complexes were affinity-purified using anti-RIP9 antibodies, and orthologs to putative Arabidopsis thaliana RNA editing factor PPR proteins, RIP2, RIP9, RIP1, OZ1, ORRM1 and ISE2 were identified via mass spectrometry. Western blots from co-IP studies revealed the mutual association of OTP86 and OZ1 with native RIP9 complexes. Thus, RIP9 complexes were discovered to be highly associated with C-to-U RNA editing activity and other editing factors indicative of their critical role in vascular plant editosomes.
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Affiliation(s)
- Rafael Sandoval
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Robert D. Boyd
- Department of Chemistry and Biochemistry, California State University Los Angeles, Los Angeles, California, 90032, USA
| | - Alena N. Kiszter
- Department of Chemistry, Graz University of Technology, Graz, Austria
| | - Yeva Mirzakhanyan
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California 92697, USA
| | - Paola Santibańez
- Department of Chemistry and Biochemistry, California State University Los Angeles, Los Angeles, California, 90032, USA
| | - Paul D. Gershon
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California 92697, USA
| | - Michael L. Hayes
- Department of Chemistry and Biochemistry, California State University Los Angeles, Los Angeles, California, 90032, USA
- To whom correspondence should be addressed. Michael L. Hayes: Department of Chemistry and Biochemistry, California State University Los Angeles, Los Angeles, CA 90032; ; Tel.(323) 343-2144
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Wang Y, Liu XY, Yang YZ, Huang J, Sun F, Lin J, Gu ZQ, Sayyed A, Xu C, Tan BC. Empty Pericarp21 encodes a novel PPR-DYW protein that is required for mitochondrial RNA editing at multiple sites, complexes I and V biogenesis, and seed development in maize. PLoS Genet 2019; 15:e1008305. [PMID: 31374076 PMCID: PMC6693784 DOI: 10.1371/journal.pgen.1008305] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 08/14/2019] [Accepted: 07/11/2019] [Indexed: 01/08/2023] Open
Abstract
C-to-U editing is an important event in post-transcriptional RNA processing, which converts a specific cytidine (C)-to-uridine (U) in transcripts of mitochondria and plastids. Typically, the pentatricopeptide repeat (PPR) protein, which specifies the target C residue by binding to its upstream sequence, is involved in the editing of one or a few sites. Here we report a novel PPR-DYW protein EMP21 that is associated with editing of 81 sites in maize. EMP21 is localized in mitochondria and loss of the EMP21 function severely inhibits the embryogenesis and endosperm development in maize. From a scan of 35 mitochondrial transcripts produced by the Emp21 loss-of-function mutant, the C-to-U editing was found to be abolished at five sites (nad7-77, atp1-1292, atp8-437, nad3-275 and rps4-870), while reduced at 76 sites in 21 transcripts. In most cases, the failure to editing resulted in the translation of an incorrect residue. In consequence, the mutant became deficient with respect to the assembly and activity of mitochondrial complexes I and V. As six of the decreased editing sites in emp21 overlap with the affected editing sites in emp5-1, and the editing efficiency at rpl16-458 showed a substantial reduction in the emp21-1 emp5-4 double mutant compared with the emp21-1 and emp5-4 single mutants, we explored their interaction. A yeast two hybrid assay suggested that EMP21 does not interact with EMP5, but both EMP21 and EMP5 interact with ZmMORF8. Together, these results indicate that EMP21 is a novel PPR-DYW protein required for the editing of ~17% of mitochondrial target Cs, and the editing process may involve an interaction between EMP21 and ZmMORF8 (and probably other proteins).
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Affiliation(s)
- Yong Wang
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Xin-Yuan Liu
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Yan-Zhuo Yang
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Jin Huang
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Feng Sun
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Jishan Lin
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhi-Qun Gu
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Aqib Sayyed
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Chunhui Xu
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
| | - Bao-Cai Tan
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China
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Fernandez JC, Burch-Smith TM. Chloroplasts as mediators of plant biotic interactions over short and long distances. CURRENT OPINION IN PLANT BIOLOGY 2019; 50:148-155. [PMID: 31284090 DOI: 10.1016/j.pbi.2019.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 05/21/2019] [Accepted: 06/05/2019] [Indexed: 06/09/2023]
Abstract
In nature, plants interact with numerous other organisms. Some interactions benefit both the plant and the other organism(s), while others lead to disease or even death of the plant hosts. The traditional focus of research into plant biotic interactions has been on the negative effects on plants and the strategies plants use to mitigate or prevent these. Over the last several years there has been increasing appreciation for the diversity and importance of plant biotic interactions in plant success as well as the evolution and stabilization of ecosystems. With this new perspective, it is also becoming clear that the metabolic output of chloroplasts in plants is critical to establishing and maintaining these interactions. Here we highlight the roles of chloroplasts in diverse biotic interactions. Photosynthetic chloroplasts are the source of hormones, small molecules and a prodigious number of secondary metabolites, a significant portion of which influence plant biotic interactions. Importantly, the effects of chloroplasts on these interactions are not limited to sites of direct association or contact but also act at a distance in systemic leaves and roots, in the rhizosphere, in the air surrounding a plant and in neighboring plants, and they can persist over several years.
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Affiliation(s)
- Jessica C Fernandez
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tessa M Burch-Smith
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States.
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Ganusova EE, Burch-Smith TM. Review: Plant-pathogen interactions through the plasmodesma prism. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 279:70-80. [PMID: 30709495 DOI: 10.1016/j.plantsci.2018.05.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 05/18/2018] [Accepted: 05/23/2018] [Indexed: 06/09/2023]
Abstract
Plasmodesmata (PD) allow membrane and cytoplasmic continuity between plant cells, and they are essential for intercellular communication and signaling in addition to metabolite partitioning. Plant pathogens have evolved a variety of mechanisms to subvert PD to facilitate their infection of plant hosts. PD are implicated not only in local spread around infection sites but also in the systemic spread of pathogens and pathogen-derived molecules. In turn, plants have developed strategies to limit pathogen spread via PD, and there is increasing evidence that PD may also be active players in plant defense responses. The last few years have seen important advances in understanding the roles of PD in plant-pathogen infection. Nonetheless, several critical areas remain to be addressed. Here we highlight some of these, focusing on the need to consider the effects of pathogen-PD interaction on the trafficking of endogenous molecules, and the involvement of chloroplasts in regulating PD during pathogen defense. By their very nature, PD are recalcitrant to most currently used investigative techniques, therefore answering these questions will require creative imaging and novel quantification approaches.
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Affiliation(s)
- Elena E Ganusova
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, United States
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, United States.
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Nawaz G, Kang H. Rice OsRH58, a chloroplast DEAD-box RNA helicase, improves salt or drought stress tolerance in Arabidopsis by affecting chloroplast translation. BMC PLANT BIOLOGY 2019; 19:17. [PMID: 30626336 PMCID: PMC6327599 DOI: 10.1186/s12870-018-1623-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 12/28/2018] [Indexed: 05/02/2023]
Abstract
BACKGROUND Despite increasing characterization of DEAD-box RNA helicases (RHs) in chloroplast gene expression regulation at posttranscriptional levels in plants, their functional roles in growth responses of crops, including rice (Oryza sativa), to abiotic stresses are yet to be characterized. In this study, rice OsRH58 (LOC_Os01g73900), a chloroplast-localized DEAD-box RH, was characterized for its expression patterns upon stress treatment and its functional roles using transgenic Arabidopsis plants under normal and abiotic stress conditions. RESULTS Chloroplast localization of OsRH58 was confirmed by analyzing the expression of OsRH58-GFP fusion proteins in tobacco leaves. Expression of OsRH58 in rice was up-regulated by salt, drought, or heat stress, whereas its expression was decreased by cold, UV, or ABA treatment. The OsRH58-expressing Arabidopsis plants were taller and had more seeds than the wild type under favorable conditions. The transgenic plants displayed faster seed germination, better seedling growth, and a higher survival rate than the wild type under high salt or drought stress. Importantly, levels of several chloroplast proteins were increased in the transgenic plants under salt or dehydration stress. Notably, OsRH58 harbored RNA chaperone activity. CONCLUSIONS These findings suggest that the chloroplast-transported OsRH58 possessing RNA chaperone activity confers stress tolerance by increasing translation of chloroplast mRNAs.
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Affiliation(s)
- Ghazala Nawaz
- Department of Applied Biology, College of Agriculture and Life Sciences, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju, 61186 South Korea
- Department of Botany, Kohat University of Science and Technology, Indus Highway Kohat, Kohat, Khyber Pakhtunkhwa 26000 Pakistan
| | - Hunseung Kang
- Department of Applied Biology, College of Agriculture and Life Sciences, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju, 61186 South Korea
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Sun Y, Huang D, Chen X. Dynamic regulation of plasmodesmatal permeability and its application to horticultural research. HORTICULTURE RESEARCH 2019; 6:47. [PMID: 30962940 PMCID: PMC6441653 DOI: 10.1038/s41438-019-0129-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 05/10/2023]
Abstract
Effective cell-to-cell communication allows plants to fine-tune their developmental processes in accordance with the prevailing environmental stimuli. Plasmodesmata (PD) are intercellular channels that span the plant cell wall and serve as cytoplasmic bridges to facilitate efficient exchange of signaling molecules between neighboring cells. The identification of PD-associated proteins and the subsequent elucidation of the regulation of PD structure have provided vital insights into the role of PD architecture in enforcing crucial cellular processes, including callose deposition, ER-Golgi-based secretion, cytoskeleton dynamics, membrane lipid raft organization, chloroplast metabolism, and cell wall formation. In this review, we summarize the emerging discoveries from recent studies that elucidated the regulatory mechanisms involved in PD biogenesis and the dynamics of PD opening-closure. Retrospectively, PD-mediated cell-to-cell communication has been implicated in diverse cellular and physiological processes that are fundamental for the development of horticultural plants. The potential application of PD biotechnological engineering represents a powerful approach for improving agronomic traits in horticultural crops in the future.
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Affiliation(s)
- Yanbiao Sun
- College of Life Science and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian China
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, 350002 China
| | - Dingquan Huang
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, 350002 China
| | - Xu Chen
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, 350002 China
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Bobik K, Fernandez JC, Hardin SR, Ernest B, Ganusova EE, Staton ME, Burch-Smith TM. The essential chloroplast ribosomal protein uL15c interacts with the chloroplast RNA helicase ISE2 and affects intercellular trafficking through plasmodesmata. THE NEW PHYTOLOGIST 2019; 221:850-865. [PMID: 30192000 DOI: 10.1111/nph.15427] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 07/24/2018] [Indexed: 05/07/2023]
Abstract
Chloroplasts retain part of their ancestral genomes and the machinery for expression of those genomes. The nucleus-encoded chloroplast RNA helicase INCREASED SIZE EXCLUSION LIMIT2 (ISE2) is required for chloroplast ribosomal RNA processing and chloro-ribosome assembly. To further elucidate ISE2's role in chloroplast translation, two independent approaches were used to identify its potential protein partners. Both a yeast two-hybrid screen and a pull-down assay identified plastid ribosomal protein L15, uL15c (formerly RPL15), as interacting with ISE2. The interaction was confirmed in vivo by co-immunoprecipitation. Interestingly, we found that rpl15 null mutants do not complete embryogenesis, indicating that RPL15 is an essential gene for autotrophic growth of Arabidopsis thaliana. Arabidopsis and Nicotiana benthamiana plants with reduced expression of RPL15 developed chlorotic leaves, had reduced photosynthetic capacity and exhibited defective chloroplast development. Processing of chloroplast ribosomal RNAs and assembly of ribosomal subunits were disrupted by reduced expression of RPL15. Chloroplast translation was also decreased, reducing accumulation of chloroplast-encoded proteins, in such plants compared to wild-type plants. Notably, knockdown of RPL15 expression increased intercellular trafficking, a phenotype also observed in plants with reduced ISE2 expression. This finding provides further evidence for chloroplast function in modulating intercellular trafficking via plasmodesmata.
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Affiliation(s)
- Krzysztof Bobik
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Jessica C Fernandez
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Sara R Hardin
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Ben Ernest
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Elena E Ganusova
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Margaret E Staton
- Department of Entomology and Plant Pathology, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA
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Reagan BC, Ganusova EE, Fernandez JC, McCray TN, Burch-Smith TM. RNA on the move: The plasmodesmata perspective. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 275:1-10. [PMID: 30107876 DOI: 10.1016/j.plantsci.2018.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/25/2018] [Accepted: 07/04/2018] [Indexed: 05/11/2023]
Abstract
It is now widely accepted that plant RNAs can have effects at sites far away from their sites of synthesis. Cellular mRNA transcripts, endogenous small RNAs and defense-related small RNAs all move from cell to cell via plasmodesmata (PD), and may even move long distances in the phloem. Despite their small size, PD have complicated substructures, and the area of the pore available for RNA trafficking can be remarkably small. The intent of this review is to bring into focus the role of PD in cell-to-cell and long distance communication in plants. We consider how cellular RNAs could move through the cell to the PD and thence through PD. The protein composition of PD and the possible roles of PD proteins in RNA trafficking are also discussed. Recent evidence for RNA metabolism in organelles acting as a factor in controlling PD flux is also presented, highlighting new aspects of plant intra- and intercellular communication. It is clear that while the phenomenon of RNA mobility is common and essential, many questions remain, and these have been highlighted throughout this review.
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Affiliation(s)
- Brandon C Reagan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Elena E Ganusova
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Jessica C Fernandez
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tyra N McCray
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States; School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, United States.
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Ties that bind: the integration of plastid signalling pathways in plant cell metabolism. Essays Biochem 2018; 62:95-107. [PMID: 29563221 DOI: 10.1042/ebc20170011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/17/2018] [Accepted: 01/22/2018] [Indexed: 12/11/2022]
Abstract
Plastids are critical organelles in plant cells that perform diverse functions and are central to many metabolic pathways. Beyond their major roles in primary metabolism, of which their role in photosynthesis is perhaps best known, plastids contribute to the biosynthesis of phytohormones and other secondary metabolites, store critical biomolecules, and sense a range of environmental stresses. Accordingly, plastid-derived signals coordinate a host of physiological and developmental processes, often by emitting signalling molecules that regulate the expression of nuclear genes. Several excellent recent reviews have provided broad perspectives on plastid signalling pathways. In this review, we will highlight recent advances in our understanding of chloroplast signalling pathways. Our discussion focuses on new discoveries illuminating how chloroplasts determine life and death decisions in cells and on studies elucidating tetrapyrrole biosynthesis signal transduction networks. We will also examine the role of a plastid RNA helicase, ISE2, in chloroplast signalling, and scrutinize intriguing results investigating the potential role of stromules in conducting signals from the chloroplast to other cellular locations.
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Lee TA, Bailey-Serres J. Lighting the shadows: methods that expose nuclear and cytoplasmic gene regulatory control. Curr Opin Biotechnol 2018; 49:29-34. [DOI: 10.1016/j.copbio.2017.07.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 07/19/2017] [Accepted: 07/21/2017] [Indexed: 12/31/2022]
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Liu Y, Imai R. Function of Plant DExD/H-Box RNA Helicases Associated with Ribosomal RNA Biogenesis. FRONTIERS IN PLANT SCIENCE 2018; 9:125. [PMID: 29472942 PMCID: PMC5809497 DOI: 10.3389/fpls.2018.00125] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/23/2018] [Indexed: 05/18/2023]
Abstract
Ribosome biogenesis is a highly complex process that requires several cofactors, including DExD/H-box RNA helicases (RHs). RHs are a family of ATPases that rearrange the secondary structures of RNA and thus remodel ribonucleoprotein complexes. DExD/H-box RHs are found in most organisms and play critical roles in a variety of RNA-involved cellular events. In human and yeast cells, many DExD/H box RHs participate in multiple steps of ribosome biogenesis and regulate cellular proliferation and stress responses. In plants, several DExD/H-box RHs have been demonstrated to be associated with plant development and abiotic stress tolerance through their functions in modulating pre-rRNA processing. In this review, we summarize the pleiotropic roles of DExD/H-box RHs in rRNA biogenesis and other biological functions. We also describe the overall function of the DExD/H-box RH family in ribosome biogenesis based on data from human and yeast.
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Sun YK, Gutmann B, Yap A, Kindgren P, Small I. Editing of Chloroplast rps14 by PPR Editing Factor EMB2261 Is Essential for Arabidopsis Development. FRONTIERS IN PLANT SCIENCE 2018; 9:841. [PMID: 29973946 PMCID: PMC6019781 DOI: 10.3389/fpls.2018.00841] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 05/30/2018] [Indexed: 05/04/2023]
Abstract
RNA editing in plastids is known to be required for embryogenesis, but no single editing event had been shown to be essential. We show that the emb2261-2 mutation is lethal through a failure to express an editing factor that specifically recognizes the rps14-2 site. EMB2261 was predicted to bind the cis-element upstream of the rps14-2 site and genetic complementation with promoters of different strength followed by RNA-seq analysis was conducted to test the correlation between rps14-2 editing and EMB2261 expression. Rps14-2 is the only editing event in Arabidopsis chloroplasts that correlates with EMB2261 expression. Sequence divergence between the cis-element and the EMB2261 protein sequence in plants where rps14-2 editing is not required adds support to the association between them. We conclude that EMB2261 is the specificity factor for rps14-2 editing. This editing event converts P51 in Rps14 to L51, which is conserved among species lacking RNA editing, implying the importance of the editing event to Rps14 function. Rps14 is an essential ribosomal subunit for plastid translation, which, in turn, is essential for Arabidopsis embryogenesis.
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