1
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Yu Q, Li H, Zhang B, Song Y, Sun Y, Ding Z. ATP Hydrolases Superfamily Protein 1 (ASP1) Maintains Root Stem Cell Niche Identity through Regulating Reactive Oxygen Species Signaling in Arabidopsis. PLANTS (BASEL, SWITZERLAND) 2024; 13:1469. [PMID: 38891278 PMCID: PMC11174532 DOI: 10.3390/plants13111469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/16/2024] [Accepted: 05/24/2024] [Indexed: 06/21/2024]
Abstract
The maintenance of the root stem cell niche identity in Arabidopsis relies on the delicate balance of reactive oxygen species (ROS) levels in root tips; however, the intricate molecular mechanisms governing ROS homeostasis within the root stem cell niche remain unclear. In this study, we unveil the role of ATP hydrolase superfamily protein 1 (ASP1) in orchestrating root stem cell niche maintenance through its interaction with the redox regulator cystathionine β-synthase domain-containing protein 3 (CBSX3). ASP1 is exclusively expressed in the quiescent center (QC) cells and governs the integrity of the root stem cell niche. Loss of ASP1 function leads to enhanced QC cell division and distal stem cell differentiation, attributable to reduced ROS levels and diminished expression of SCARECROW and SHORT ROOT in root tips. Our findings illuminate the pivotal role of ASP1 in regulating ROS signaling to maintain root stem cell niche homeostasis, achieved through direct interaction with CBSX3.
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Affiliation(s)
- Qianqian Yu
- School of Life Sciences, Liaocheng University, Liaocheng 252000, China; (H.L.); (B.Z.); (Y.S.); (Y.S.)
| | - Hongyu Li
- School of Life Sciences, Liaocheng University, Liaocheng 252000, China; (H.L.); (B.Z.); (Y.S.); (Y.S.)
| | - Bing Zhang
- School of Life Sciences, Liaocheng University, Liaocheng 252000, China; (H.L.); (B.Z.); (Y.S.); (Y.S.)
| | - Yun Song
- School of Life Sciences, Liaocheng University, Liaocheng 252000, China; (H.L.); (B.Z.); (Y.S.); (Y.S.)
| | - Yueying Sun
- School of Life Sciences, Liaocheng University, Liaocheng 252000, China; (H.L.); (B.Z.); (Y.S.); (Y.S.)
| | - Zhaojun Ding
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao 266237, China;
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2
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Yao WJ, Wang YP, Peng J, Yin PP, Gao H, Xu L, Laux T, Zhang XS, Su YH. The RPT2a-MET1 axis regulates TERMINAL FLOWER1 to control inflorescence meristem indeterminacy in Arabidopsis. THE PLANT CELL 2024; 36:1718-1735. [PMID: 37795677 PMCID: PMC11062425 DOI: 10.1093/plcell/koad249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 08/14/2023] [Accepted: 09/01/2023] [Indexed: 10/06/2023]
Abstract
Plant inflorescence architecture is determined by inflorescence meristem (IM) activity and controlled by genetic mechanisms associated with environmental factors. In Arabidopsis (Arabidopsis thaliana), TERMINAL FLOWER1 (TFL1) is expressed in the IM and is required to maintain indeterminate growth, whereas LEAFY (LFY) is expressed in the floral meristems (FMs) formed at the periphery of the IM and is required to activate determinate floral development. Here, we address how Arabidopsis indeterminate inflorescence growth is determined. We show that the 26S proteasome subunit REGULATORY PARTICLE AAA-ATPASE 2a (RPT2a) is required to maintain the indeterminate inflorescence architecture in Arabidopsis. rpt2a mutants display reduced TFL1 expression levels and ectopic LFY expression in the IM and develop a determinate zigzag-shaped inflorescence. We further found that RPT2a promotes DNA METHYLTRANSFERASE1 degradation, leading to DNA hypomethylation upstream of TFL1 and high TFL1 expression levels in the wild-type IM. Overall, our work reveals that proteolytic input into the epigenetic regulation of TFL1 expression directs inflorescence architecture in Arabidopsis, adding an additional layer to stem cell regulation.
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Affiliation(s)
- Wang Jinsong Yao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Yi Peng Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Jing Peng
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Pei Pei Yin
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Hengbin Gao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Li Xu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Thomas Laux
- Sino-German Joint Research Center on Agricultural Biology, Shandong Agricultural University, Tai’an, Shandong 271018, China
- Signalling Research Centres BIOSS and CIBSS, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Xian Sheng Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
| | - Ying Hua Su
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China
- Sino-German Joint Research Center on Agricultural Biology, Shandong Agricultural University, Tai’an, Shandong 271018, China
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3
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Viñegra de la Torre N, Vayssières A, Obeng-Hinneh E, Neumann U, Zhou Y, Lázaro A, Roggen A, Sun H, Stolze SC, Nakagami H, Schneeberger K, Timmers T, Albani MC. FLOWERING REPRESSOR AAA + ATPase 1 is a novel regulator of perennial flowering in Arabis alpina. THE NEW PHYTOLOGIST 2022; 236:729-744. [PMID: 35832005 DOI: 10.1111/nph.18374] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Arabis alpina is a polycarpic perennial, in which PERPETUAL FLOWERING1 (PEP1) regulates flowering and perennial traits in a vernalization-dependent manner. Mutagenesis screens of the pep1 mutant established the role of other flowering time regulators in PEP1-parallel pathways. Here we characterized three allelic enhancers of pep1 (eop002, 085 and 091) which flower early. We mapped the causal mutations and complemented mutants with the identified gene. Using quantitative reverse transcriptase PCR and reporter lines, we determined the protein spatiotemporal expression patterns and localization within the cell. We also characterized its role in Arabidopsis thaliana using CRISPR and in A. alpina by introgressing mutant alleles into a wild-type background. These mutants carried lesions in an AAA+ ATPase of unknown function, FLOWERING REPRESSOR AAA+ ATPase 1 (AaFRAT1). AaFRAT1 was detected in the vasculature of young leaf primordia and the rib zone of flowering shoot apical meristems. At the subcellular level, AaFRAT1 was localized at the interphase between the endoplasmic reticulum and peroxisomes. Introgression lines carrying Aafrat1 alleles required less vernalization to flower and reduced number of vegetative axillary branches. By contrast, A. thaliana CRISPR lines showed weak flowering phenotypes. AaFRAT1 contributes to flowering time regulation and the perennial growth habit of A. alpina.
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Affiliation(s)
- Natanael Viñegra de la Torre
- Institute for Plant Sciences, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
- Cluster of Excellence on Plant Sciences "From Complex Traits towards Synthetic Modules", 40225, Düsseldorf, Germany
| | - Alice Vayssières
- Institute for Plant Sciences, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
- Cluster of Excellence on Plant Sciences "From Complex Traits towards Synthetic Modules", 40225, Düsseldorf, Germany
| | - Evelyn Obeng-Hinneh
- Institute for Plant Sciences, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
- Cluster of Excellence on Plant Sciences "From Complex Traits towards Synthetic Modules", 40225, Düsseldorf, Germany
| | - Ulla Neumann
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Yanhao Zhou
- Institute for Plant Sciences, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
- Cluster of Excellence on Plant Sciences "From Complex Traits towards Synthetic Modules", 40225, Düsseldorf, Germany
| | - Ana Lázaro
- Institute for Plant Sciences, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
- Cluster of Excellence on Plant Sciences "From Complex Traits towards Synthetic Modules", 40225, Düsseldorf, Germany
| | - Adrian Roggen
- Institute for Plant Sciences, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Hequan Sun
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Sara C Stolze
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Hirofumi Nakagami
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Korbinian Schneeberger
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Ton Timmers
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Maria C Albani
- Institute for Plant Sciences, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829, Cologne, Germany
- Cluster of Excellence on Plant Sciences "From Complex Traits towards Synthetic Modules", 40225, Düsseldorf, Germany
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The RPN12a proteasome subunit is essential for the multiple hormonal homeostasis controlling the progression of leaf senescence. Commun Biol 2022; 5:1043. [PMID: 36180574 PMCID: PMC9525688 DOI: 10.1038/s42003-022-03998-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 09/14/2022] [Indexed: 11/09/2022] Open
Abstract
The 26S proteasome is a conserved multi-subunit machinery in eukaryotes. It selectively degrades ubiquitinated proteins, which in turn provides an efficient molecular mechanism to regulate numerous cellular functions and developmental processes. Here, we studied a new loss-of-function allele of RPN12a, a plant ortholog of the yeast and human structural component of the 19S proteasome RPN12. Combining a set of biochemical and molecular approaches, we confirmed that a rpn12a knock-out had exacerbated 20S and impaired 26S activities. The altered proteasomal activity led to a pleiotropic phenotype affecting both the vegetative growth and reproductive phase of the plant, including a striking repression of leaf senescence associate cell-death. Further investigation demonstrated that RPN12a is involved in the regulation of several conjugates associated with the auxin, cytokinin, ethylene and jasmonic acid homeostasis. Such enhanced aptitude of plant cells for survival in rpn12a contrasts with reports on animals, where 26S proteasome mutants generally show an accelerated cell death phenotype.
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5
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Singh M, Singh A, Yadav N, Yadav DK. Current perspectives of ubiquitination and SUMOylation in abiotic stress tolerance in plants. FRONTIERS IN PLANT SCIENCE 2022; 13:993194. [PMID: 36212351 PMCID: PMC9533872 DOI: 10.3389/fpls.2022.993194] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/16/2022] [Indexed: 06/16/2023]
Abstract
Post-translational modification (PTM) is a critical and rapid mechanism to regulate all the major cellular processes through the modification of diverse protein substrates. Substrate-specific covalent attachment of ubiquitin and Small Ubiquitin-Like Modifier (SUMO) with the target proteins, known as ubiquitination and SUMOylation, respectively, are crucial PTMs that regulate almost every process in the cell by modulating the stability and fidelity of the proteins. Ubiquitination and SUMOylation play a very significant role to provide tolerance to the plants in adverse environmental conditions by activating/deactivating the pre-existing proteins to a great extent. We reviewed the importance of ubiquitination and SUMOylation in plants, implicating its prospects in various abiotic stress regulations. An exhaustive study of molecular mechanisms of ubiquitination and SUMOylation of plant proteins and their role will contribute to the understanding of physiology underlying mitigation of the abiotic stresses and survival in plants. It will be helpful to strategize the improvement of crops for abiotic stress tolerance.
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Affiliation(s)
- Madhavi Singh
- Plant Molecular Biology and Genetic Engineering Laboratory, Department of Botany, University of Allahabad, Prayagraj, India
| | - Ananya Singh
- Plant Molecular Biology and Genetic Engineering Laboratory, Department of Botany, University of Allahabad, Prayagraj, India
| | - Neelam Yadav
- Department of Botany, University of Allahabad, Prayagraj, India
| | - Dinesh Kumar Yadav
- Plant Molecular Biology and Genetic Engineering Laboratory, Department of Botany, University of Allahabad, Prayagraj, India
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6
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Kanaoka MM, Shimizu KK, Xie B, Urban S, Freeman M, Hong Z, Okada K. KOMPEITO, an Atypical Arabidopsis Rhomboid-Related Gene, Is Required for Callose Accumulation and Pollen Wall Development. Int J Mol Sci 2022; 23:5959. [PMID: 35682638 PMCID: PMC9180352 DOI: 10.3390/ijms23115959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/20/2022] [Accepted: 05/20/2022] [Indexed: 11/30/2022] Open
Abstract
Fertilization is a key event for sexually reproducing plants. Pollen-stigma adhesion, which is the first step in male-female interaction during fertilization, requires proper pollen wall patterning. Callose, which is a β-1.3-glucan, is an essential polysaccharide that is required for pollen development and pollen wall formation. Mutations in CALLOSE SYNTHASE 5 (CalS5) disrupt male meiotic callose accumulation; however, how CalS5 activity and callose synthesis are regulated is not fully understood. In this paper, we report the isolation of a kompeito-1 (kom-1) mutant defective in pollen wall patterning and pollen-stigma adhesion in Arabidopsis thaliana. Callose was not accumulated in kom-1 meiocytes or microspores, which was very similar to the cals5 mutant. The KOM gene encoded a member of a subclass of Rhomboid serine protease proteins that lacked active site residues. KOM was localized to the Golgi apparatus, and both KOM and CalS5 genes were highly expressed in meiocytes. A 220 kDa CalS5 protein was detected in wild-type (Col-0) floral buds but was dramatically reduced in kom-1. These results suggested that KOM was required for CalS5 protein accumulation, leading to the regulation of meiocyte-specific callose accumulation and pollen wall formation.
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Affiliation(s)
- Masahiro M. Kanaoka
- Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-Cho, Sakyo-Ku, Kyoto 606-8502, Japan; (K.K.S.); (K.O.)
- Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, ID 83844, USA; (B.X.); (Z.H.)
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Kentaro K. Shimizu
- Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-Cho, Sakyo-Ku, Kyoto 606-8502, Japan; (K.K.S.); (K.O.)
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
- Kihara Institute for Biological Research, Yokohama City University, Yokohama 244-0813, Japan
| | - Bo Xie
- Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, ID 83844, USA; (B.X.); (Z.H.)
| | - Sinisa Urban
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;
| | - Matthew Freeman
- Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK;
| | - Zonglie Hong
- Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, ID 83844, USA; (B.X.); (Z.H.)
| | - Kiyotaka Okada
- Department of Botany, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-Cho, Sakyo-Ku, Kyoto 606-8502, Japan; (K.K.S.); (K.O.)
- Ryukoku Extension Center (REC) Ryukoku University, Yokotani 1-5, Seta Ohe-cho, Otsu-shi 520-2194, Japan
- Core Research of Science and Technology (CREST) Research Project, Tokyo 102-0076, Japan
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7
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García-Gómez ML, Garay-Arroyo A, García-Ponce B, Sánchez MDLP, Álvarez-Buylla ER. Hormonal Regulation of Stem Cell Proliferation at the Arabidopsis thaliana Root Stem Cell Niche. FRONTIERS IN PLANT SCIENCE 2021; 12:628491. [PMID: 33747009 PMCID: PMC7966715 DOI: 10.3389/fpls.2021.628491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/12/2021] [Indexed: 05/13/2023]
Abstract
The root stem cell niche (SCN) of Arabidopsis thaliana consists of the quiescent center (QC) cells and the surrounding initial stem cells that produce progeny to replenish all the tissues of the root. The QC cells divide rather slowly relative to the initials, yet most root tissues can be formed from these cells, depending on the requirements of the plant. Hormones are fundamental cues that link such needs with the cell proliferation and differentiation dynamics at the root SCN. Nonetheless, the crosstalk between hormone signaling and the mechanisms that regulate developmental adjustments is still not fully understood. Developmental transcriptional regulatory networks modulate hormone biosynthesis, metabolism, and signaling, and conversely, hormonal responses can affect the expression of transcription factors involved in the spatiotemporal patterning at the root SCN. Hence, a complex genetic-hormonal regulatory network underlies root patterning, growth, and plasticity in response to changing environmental conditions. In this review, we summarize the scientific literature regarding the role of hormones in the regulation of QC cell proliferation and discuss how hormonal signaling pathways may be integrated with the gene regulatory network that underlies cell fate in the root SCN. The conceptual framework we present aims to contribute to the understanding of the mechanisms by which hormonal pathways act as integrators of environmental cues to impact on SCN activity.
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Affiliation(s)
- Mónica L. García-Gómez
- Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Adriana Garay-Arroyo
- Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Berenice García-Ponce
- Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - María de la Paz Sánchez
- Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Elena R. Álvarez-Buylla
- Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
- *Correspondence: Elena R. Álvarez-Buylla,
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8
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Wu J, Peled-Zehavi H, Galili G. The m 6 A reader ECT2 post-transcriptionally regulates proteasome activity in Arabidopsis. THE NEW PHYTOLOGIST 2020; 228:151-162. [PMID: 32416015 DOI: 10.1111/nph.16660] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/29/2020] [Indexed: 05/23/2023]
Abstract
Methylation of internal adenosine at nitrogen-6 position (m6 A) is the most abundant post-transcriptional modification in eukaryotic RNAs. These modifications are recognized by m6 A-binding proteins ('readers') that affect downstream functions. In plants, the scope of gene expression regulation by reader proteins is not clear. Here, overexpression and loss-of-function mutants were used to characterize the role of the Arabidopsis m6 A reader ECT2 in proteasome regulation. ECT2 regulates the mRNA levels of the proteasome regulator PTRE1 and of several 20S proteasome subunits, resulting in enhanced 26S proteasome activity. This regulation is dependent on ECT2 m6 A binding function. Interestingly, though ECT2 positively regulates proteasome activity in both young and mature plants, PTRE1 has different regulatory effects in different developmental stages. In mature plants, PTRE1 inhibits 26S proteasome activity, while in seedlings PTRE1 knockout mutants have reduced 26S proteasome activity. Taken together, our results suggest a novel epitranscriptomic mechanism of proteasome regulation by ECT2 that is used to fine tune proteasome activity by affecting the expression of PTRE1 and 20S proteasome subunits.
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Affiliation(s)
- Jian Wu
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Hadas Peled-Zehavi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Gad Galili
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
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9
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Wawrzyńska A, Sirko A. Proteasomal Degradation of Proteins Is Important for the Proper Transcriptional Response to Sulfur Deficiency Conditions in Plants. PLANT & CELL PHYSIOLOGY 2020; 61:1548-1564. [PMID: 32502259 PMCID: PMC7511249 DOI: 10.1093/pcp/pcaa076] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 05/29/2020] [Indexed: 05/11/2023]
Abstract
Plants are continuously exposed to different abiotic and biotic stresses; therefore, to protect themselves, they depend on the fast reprogramming of large gene repertoires to prioritize the expression of a given stress-induced gene set over normal cellular household genes. The activity of the proteasome, a large proteolytic complex that degrades proteins, is vital to coordinate the expression of such genes. Proteins are labeled for degradation by the action of E3 ligases that site-specifically alter their substrates by adding chains of ubiquitin. Recent publications have revealed an extensive role of ubiquitination in the utilization of nutrients. This study presents the transcriptomic profiles of sulfur-deficient rosettes and roots of Arabidopsis thaliana rpt2a mutant with proteasomal malfunction. We found that genes connected with sulfur metabolism are regulated to the lesser extent in rpt2a mutant while genes encoding transfer RNAs and small nucleolar RNAs are highly upregulated. Several genes encoding E3 ligases are specifically regulated by sulfur deficiency. Furthermore, we show that a key transcription factor of sulfur deficiency response, Sulfur LIMitation1, undergoes proteasomal degradation and is able to interact with F-box protein, EBF1.
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Affiliation(s)
- Anna Wawrzyńska
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawinskiego 5A St, 02-106 Warsaw, Poland
- Corresponding author: E-mail, ; Fax, +48 22 5922190
| | - Agnieszka Sirko
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawinskiego 5A St, 02-106 Warsaw, Poland
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10
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Protective Roles of Cytosolic and Plastidal Proteasomes on Abiotic Stress and Pathogen Invasion. PLANTS 2020; 9:plants9070832. [PMID: 32630761 PMCID: PMC7412383 DOI: 10.3390/plants9070832] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 06/30/2020] [Accepted: 06/30/2020] [Indexed: 01/18/2023]
Abstract
Protein malfunction is typically caused by abiotic stressors. To ensure cell survival during conditions of stress, it is important for plant cells to maintain proteins in their respective functional conformation. Self-compartmentalizing proteases, such as ATP-dependent Clp proteases and proteasomes are designed to act in the crowded cellular environment, and they are responsible for degradation of misfolded or damaged proteins within the cell. During different types of stress conditions, the levels of misfolded or orphaned proteins that are degraded by the 26S proteasome in the cytosol and nucleus and by the Clp proteases in the mitochondria and chloroplasts increase. This allows cells to uphold feedback regulations to cellular-level signals and adjust to altered environmental conditions. In this review, we summarize recent findings on plant proteolytic complexes with respect to their protective functions against abiotic and biotic stressors.
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11
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Zhou SR, Xue HW. The rice PLATZ protein SHORT GRAIN6 determines grain size by regulating spikelet hull cell division. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2020; 62:847-864. [PMID: 31207036 DOI: 10.1111/jipb.12851] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 06/13/2019] [Indexed: 05/12/2023]
Abstract
Grain size is a major determinant of cereal grain yields; however, the relevant regulatory mechanisms controlling this trait have not been fully elucidated. The rice (Oryza sativa) mutant short grain6 (sg6) was identified based on its reduced grain length and weight. Here, we functionally characterized the role of SG6 in determining grain size through the regulation of spikelet hull cell division. SG6 encodes a previously uncharacterized plant AT-rich sequence and zinc-binding (PLATZ) protein that is ubiquitously localized throughout the cell and is preferentially expressed in the early developing panicles but not in the endosperm. The overexpression of SG6 resulted in significantly larger and heavier grains, as well as increased plant heights, which is consistent with its elevated spikelet hull cell division rate. Yeast two-hybrid analyses revealed that SG6 interacts with the core cell cycle machinery DP protein and several other putative cell division regulators, consistent with our transcriptomic analysis, which showed that SG6 activates the expression of many DNA replication and cell-cycle-related genes. These results confirm the crucial role of SG6 in determining grain size by regulating spikelet hull cell division and provide clues for understanding the functions of PLATZ family proteins and the network regulating cereal grain size.
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Affiliation(s)
- Shi-Rong Zhou
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, the Chinese Academy of Sciences, Shanghai, 200032, China
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Hong-Wei Xue
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, the Chinese Academy of Sciences, Shanghai, 200032, China
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
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12
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Vercruysse J, Van Bel M, Osuna‐Cruz CM, Kulkarni SR, Storme V, Nelissen H, Gonzalez N, Inzé D, Vandepoele K. Comparative transcriptomics enables the identification of functional orthologous genes involved in early leaf growth. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:553-567. [PMID: 31361386 PMCID: PMC6953196 DOI: 10.1111/pbi.13223] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/10/2019] [Accepted: 07/25/2019] [Indexed: 05/20/2023]
Abstract
Leaf growth is a complex trait for which many similarities exist in different plant species, suggesting functional conservation of the underlying pathways. However, a global view of orthologous genes involved in leaf growth showing conserved expression in dicots and monocots is currently missing. Here, we present a genome-wide comparative transcriptome analysis between Arabidopsis and maize, identifying conserved biological processes and gene functions active during leaf growth. Despite the orthology complexity between these distantly related plants, 926 orthologous gene groups including 2829 Arabidopsis and 2974 maize genes with similar expression during leaf growth were found, indicating conservation of the underlying molecular networks. We found 65% of these genes to be involved in one-to-one orthology, whereas only 28.7% of the groups with divergent expression had one-to-one orthology. Within the pool of genes with conserved expression, 19 transcription factor families were identified, demonstrating expression conservation of regulators active during leaf growth. Additionally, 25 Arabidopsis and 25 maize putative targets of the TCP transcription factors with conserved expression were determined based on the presence of enriched transcription factor binding sites. Based on large-scale phenotypic data, we observed that genes with conserved expression have a higher probability to be involved in leaf growth and that leaf-related phenotypes are more frequently present for genes having orthologues between dicots and monocots than clade-specific genes. This study shows the power of integrating transcriptomic with orthology data to identify or select candidates for functional studies during leaf development in flowering plants.
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Affiliation(s)
- Jasmien Vercruysse
- Department of Plant Biotechnology and BioinformaticsGhent UniversityGentBelgium
- Center for Plant Systems BiologyVIBGentBelgium
| | - Michiel Van Bel
- Department of Plant Biotechnology and BioinformaticsGhent UniversityGentBelgium
- Center for Plant Systems BiologyVIBGentBelgium
| | - Cristina M. Osuna‐Cruz
- Department of Plant Biotechnology and BioinformaticsGhent UniversityGentBelgium
- Center for Plant Systems BiologyVIBGentBelgium
| | - Shubhada R. Kulkarni
- Department of Plant Biotechnology and BioinformaticsGhent UniversityGentBelgium
- Center for Plant Systems BiologyVIBGentBelgium
| | - Véronique Storme
- Department of Plant Biotechnology and BioinformaticsGhent UniversityGentBelgium
- Center for Plant Systems BiologyVIBGentBelgium
| | - Hilde Nelissen
- Department of Plant Biotechnology and BioinformaticsGhent UniversityGentBelgium
- Center for Plant Systems BiologyVIBGentBelgium
| | - Nathalie Gonzalez
- Department of Plant Biotechnology and BioinformaticsGhent UniversityGentBelgium
- Center for Plant Systems BiologyVIBGentBelgium
- INRAUMR1332 Biologie du fruit et PathologieINRA Bordeaux AquitaineVillenave d'Ornon CedexFrance
| | - Dirk Inzé
- Department of Plant Biotechnology and BioinformaticsGhent UniversityGentBelgium
- Center for Plant Systems BiologyVIBGentBelgium
| | - Klaas Vandepoele
- Department of Plant Biotechnology and BioinformaticsGhent UniversityGentBelgium
- Center for Plant Systems BiologyVIBGentBelgium
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13
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Xu FQ, Xue HW. The ubiquitin-proteasome system in plant responses to environments. PLANT, CELL & ENVIRONMENT 2019; 42:2931-2944. [PMID: 31364170 DOI: 10.1111/pce.13633] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 05/12/2023]
Abstract
The ubiquitin-proteasome system (UPS) is a rapid regulatory mechanism for selective protein degradation in plants and plays crucial roles in growth and development. There is increasing evidence that the UPS is also an integral part of plant adaptation to environmental stress, such as drought, salinity, cold, nutrient deprivation and pathogens. This review focuses on recent studies illustrating the important functions of the UPS components E2s, E3s and subunits of the proteasome and describes the regulation of proteasome activity during plant responses to environment stimuli. The future research hotspots and the potential for utilization of the UPS to improve plant tolerance to stress are discussed.
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Affiliation(s)
- Fa-Qing Xu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
- Shanghai College of Life Science, University of Chinese Academy of Sciences, 200032, Shanghai, China
| | - Hong-Wei Xue
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
- School of Agriculture and Biology, Shanghai Jiao Tong University, 200240, Shanghai, China
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14
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Zhao W, Chao H, Zhang L, Ta N, Zhao Y, Li B, Zhang K, Guan Z, Hou D, Chen K, Li H, Zhang L, Wang H, Li M. Integration of QTL Mapping and Gene Fishing Techniques to Dissect the Multi-Main Stem Trait in Rapeseed ( Brassica napus L.). FRONTIERS IN PLANT SCIENCE 2019; 10:1152. [PMID: 31616451 PMCID: PMC6764107 DOI: 10.3389/fpls.2019.01152] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 08/23/2019] [Indexed: 05/31/2023]
Abstract
Rapeseed is one of the most important oilseed crops in the world. Improving the production of rapeseed is beneficial to relieve the shortage of edible vegetable oil. As the organ of support and transport, the main stem of rapeseed controls the plant architecture, transports the water and nutrients, and determines the number of inflorescence. Increasing the number of main stems would be helpful for the yield improvement in Brassica napus (B. napus). This attractive multi-main stem (MMS) trait was observed in the KN DH population. We investigated not only the frequency of MMS traits but also dissected the genetic basis with QTL mapping analysis and Gene-Fishing technique. A total of 43 QTLs were identified for MMS based on high-density linkage map, which explained 2.95-14.9% of the phenotypic variation, among which two environmental stable QTLs (cqMMS.A3-2 and cqMMS.C3-5) were identified in winter and semi-winter environments. Epistatic interaction analysis indicated cqMMS.C3-5 was an important loci for MMS. According to the functional annotation, 159 candidate genes within QTL confidence intervals, corresponding to 148 Arabidopsis thaliana (A. thaliana) homologous genes, were identified, which regulated lateral bud development and tiller of stem, such as shoot meristemless (STM), WUSCHEL-regulated-related genes, cytokinin response factors (CRF5), cytokinin oxidase (CKX4), gibberellin-regulated (RDK1), auxin-regulated gene (ARL, IAR4), and auxin-mediated signaling gene (STV1). Based on Gene-Fishing analysis between the natural plants and the double-main stem (DMS) plant, 31 differentially expressed genes (DEGs) were also obtained, which were related to differentiation and formation of lateral buds, biotic stimulus, defense response, drought and salt-stress responses, as well as cold-response functional genes. In addition, by combining the candidate genes in QTL regions with the DEGs that were obtained by Gene-Fishing technique, six common candidate genes (RPT2A, HLR, CRK, LRR-RLK, AGL79, and TCTP) were identified, which might probably be related to the formation of MMS phenotype. The present results not only would give a new insight into the genetic basis underlying the regulation of MMS but also would provide clues for plant architecture breeding in rapeseed.
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Affiliation(s)
- Weiguo Zhao
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Hongbo Chao
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Lina Zhang
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Na Ta
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Yajun Zhao
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Baojun Li
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Kai Zhang
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Zhoubo Guan
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Dalin Hou
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Kang Chen
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Huaixin Li
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Libin Zhang
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Hao Wang
- Hybrid Rape Research Center of Shaanxi Province, Shaanxi Rapeseed Branch of National Centre for Oil Crops Genetic Improvement, Yangling, China
| | - Maoteng Li
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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15
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Yu M, Meng B, Wang F, He Z, Hu R, Du J, Lai J, Yang C. A SUMO ligase AtMMS21 regulates activity of the 26S proteasome in root development. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 280:314-320. [PMID: 30824010 DOI: 10.1016/j.plantsci.2018.12.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 05/20/2023]
Abstract
The 26S proteasome is a multi-subunit protease controlling most of the cytosolic and nuclear protein turnover, regulating many cellular events in eukaryotes. However, functional modification on this complex remains unclear. Here, we showed a novel mechanism that a SUMO ligase AtMMS21 regulates activity of the 26S proteasome in root development of Arabidopsis. Our in vitro and in vivo data supported that AtMMS21 interacts with RPT2a, a subunit of the 26S proteasome. The mutants of AtMMS21 and RPT2a display similar developmental defect of roots, suggesting their association in this process. In addition, RPT2a is modified by SUMO3, potentially related to AtMMS21. During development, the activity of the 26S proteasome is lower in both mutants of AtMMS21 and RPT2a, compared with that of wild type. Furthermore, the protein level but not the RNA level of RPT2a is decreased in the absence of AtMMS21, implying stability regulation of the proteasome complex through the AtMMS21-RPT2a interaction. Taken together, the current study would improve our understanding on the regulatory mechanism of the 26S proteasome via protein modification in root development.
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Affiliation(s)
- Mengyuan Yu
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou, 510631, China
| | - Bolun Meng
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou, 510631, China
| | - Feige Wang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou, 510631, China
| | - Zhipeng He
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou, 510631, China
| | - Risheng Hu
- Central South Agricultural Experiment Station of China Tobacco, Changsha, 410004, China
| | - Jinju Du
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou, 510631, China
| | - Jianbin Lai
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou, 510631, China.
| | - Chengwei Yang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou, 510631, China.
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16
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Bajaj R, Huang Y, Gebrechristos S, Mikolajczyk B, Brown H, Prasad R, Varma A, Bushley KE. Transcriptional responses of soybean roots to colonization with the root endophytic fungus Piriformospora indica reveals altered phenylpropanoid and secondary metabolism. Sci Rep 2018; 8:10227. [PMID: 29980739 PMCID: PMC6035220 DOI: 10.1038/s41598-018-26809-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 05/15/2018] [Indexed: 12/31/2022] Open
Abstract
Piriformospora indica, a root endophytic fungus, has been shown to enhance biomass production and confer tolerance to various abiotic and biotic stresses in many plant hosts. A growth chamber experiment of soybean (Glycine max) colonized by P. indica compared to uninoculated control plants showed that the fungus significantly increased shoot dry weight, nutrient content, and rhizobial biomass. RNA-Seq analyses of root tissue showed upregulation of 61 genes and downregulation of 238 genes in colonized plants. Gene Ontology (GO) enrichment analyses demonstrated that upregulated genes were most significantly enriched in GO categories related to lignin biosynthesis and regulation of iron transport and metabolism but also mapped to categories of nutrient acquisition, hormone signaling, and response to drought stress. Metabolic pathway analysis revealed upregulation of genes within the phenylpropanoid and derivative pathways such as biosynthesis of monolignol subunits, flavonoids and flavonols (luteolin and quercetin), and iron scavenging siderophores. Highly enriched downregulated GO categories included heat shock proteins involved in response to heat, high-light intensity, hydrogen peroxide, and several related to plant defense. Overall, these results suggest that soybean maintains an association with this root endosymbiotic fungus that improves plant growth and nutrient acquisition, modulates abiotic stress, and promotes synergistic interactions with rhizobia.
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Affiliation(s)
- Ruchika Bajaj
- Department of Plant Biology, University of Minnesota, Saint Paul, MN, USA
- Amity Institute of Microbial Technology, Amity University, Uttar Pradesh, Noida, India
| | - Yinyin Huang
- Department of Plant Biology, University of Minnesota, Saint Paul, MN, USA
| | - Sebhat Gebrechristos
- Master of Biological Sciences Program, University of Minnesota, Saint Paul, MN, USA
| | - Brian Mikolajczyk
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - Heather Brown
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Ram Prasad
- Amity Institute of Microbial Technology, Amity University, Uttar Pradesh, Noida, India
| | - Ajit Varma
- Amity Institute of Microbial Technology, Amity University, Uttar Pradesh, Noida, India
| | - Kathryn E Bushley
- Department of Plant Biology, University of Minnesota, Saint Paul, MN, USA.
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17
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Genetic Interactions Between BOB1 and Multiple 26S Proteasome Subunits Suggest a Role for Proteostasis in Regulating Arabidopsis Development. G3-GENES GENOMES GENETICS 2018; 8:1379-1390. [PMID: 29487187 PMCID: PMC5873925 DOI: 10.1534/g3.118.300496] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Protein folding and degradation are both required for protein quality control, an essential cellular activity that underlies normal growth and development. We investigated how BOB1, an Arabidopsis thaliana small heat shock protein, maintains normal plant development. bob1 mutants exhibit organ polarity defects and have expanded domains of KNOX gene expression. Some of these phenotypes are ecotype specific suggesting that other genes function to modify them. Using a genetic approach we identified an interaction between BOB1 and FIL, a gene required for abaxial organ identity. We also performed an EMS enhancer screen using the bob1-3 allele to identify pathways that are sensitized by a loss of BOB1 function. This screen identified genetic, but not physical, interactions between BOB1 and the proteasome subunit RPT2a. Two other proteasome subunits, RPN1a and RPN8a, also interact genetically with BOB1. Both BOB1 and the BOB1-interacting proteasome subunits had previously been shown to interact genetically with the transcriptional enhancers AS1 and AS2, genes known to regulate both organ polarity and KNOX gene expression. Our results suggest a model in which BOB1 mediated protein folding and proteasome mediated protein degradation form a functional proteostasis module required for ensuring normal plant development.
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18
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Bulgakov VP, Vereshchagina YV, Bulgakov DV, Veremeichik GN, Shkryl YN. The rolB plant oncogene affects multiple signaling protein modules related to hormone signaling and plant defense. Sci Rep 2018; 8:2285. [PMID: 29396465 PMCID: PMC5797197 DOI: 10.1038/s41598-018-20694-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 01/23/2018] [Indexed: 01/11/2023] Open
Abstract
The rolB plant oncogene of Agrobacterium rhizogenes perturbs many biochemical processes in transformed plant cells, thereby causing their neoplastic reprogramming. The oncogene renders the cells more tolerant to environmental stresses and herbicides and inhibits ROS elevation and programmed cell death. In the present work, we performed a proteomic analysis of Arabidopsis thaliana rolB-expressing callus line AtB-2, which represents a line with moderate expression of the oncogene. Our results show that under these conditions rolB greatly perturbs the expression of some chaperone-type proteins such as heat-shock proteins and cyclophilins. Heat-shock proteins of the DnaK subfamily were overexpressed in rolB-transformed calli, whereas the abundance of cyclophilins, members of the closely related single-domain cyclophilin family was decreased. Real-time PCR analysis of corresponding genes confirmed the reliability of proteomics data because gene expression correlated well with the expression of proteins. Bioinformatics analysis indicates that rolB can potentially affect several levels of signaling protein modules, including effector-triggered immunity (via the RPM1-RPS2 signaling module), the miRNA processing machinery, auxin and cytokinin signaling, the calcium signaling system and secondary metabolism.
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Affiliation(s)
- Victor P Bulgakov
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok, 690022, Russia. .,Far Eastern Federal University, Vladivostok, 690950, Russia.
| | - Yulia V Vereshchagina
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok, 690022, Russia
| | - Dmitry V Bulgakov
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok, 690022, Russia
| | - Galina N Veremeichik
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok, 690022, Russia
| | - Yuri N Shkryl
- Institute of Biology and Soil Science, Far Eastern Branch of the Russian Academy of Sciences, 159 Stoletija Str., Vladivostok, 690022, Russia
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19
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Witzel K, Üstün S, Schreiner M, Grosch R, Börnke F, Ruppel S. A Proteomic Approach Suggests Unbalanced Proteasome Functioning Induced by the Growth-Promoting Bacterium Kosakonia radicincitans in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2017; 8:661. [PMID: 28491076 PMCID: PMC5405128 DOI: 10.3389/fpls.2017.00661] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 04/11/2017] [Indexed: 06/07/2023]
Abstract
Endophytic plant growth-promoting bacteria have significant impact on the plant physiology and understanding this interaction at the molecular level is of particular interest to support crop productivity and sustainable production systems. We used a proteomics approach to investigate the molecular mechanisms underlying plant growth promotion in the interaction of Kosakonia radicincitans DSM 16656 with Arabidopsis thaliana. Four weeks after the inoculation, the proteome of roots from inoculated and control plants was compared using two-dimensional gel electrophoresis and differentially abundant protein spots were identified by liquid chromatography tandem mass spectrometry. Twelve protein spots were responsive to the inoculation, with the majority of them being related to cellular stress reactions. The protein expression of 20S proteasome alpha-3 subunit was increased by the presence of K. radicincitans. Determination of proteasome activity and immuno blotting analysis for ubiquitinated proteins revealed that endophytic colonization interferes with ubiquitin-dependent protein degradation. Inoculation of rpn12a, defective in a 26S proteasome regulatory particle, enhanced the growth-promoting effect. This indicates that the plant proteasome, besides being a known target for plant pathogenic bacteria, is involved in the establishment of beneficial interactions of microorganisms with plants.
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Affiliation(s)
- Katja Witzel
- Leibniz Institute of Vegetable and Ornamental CropsGroßbeeren, Germany
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20
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Liu SJ, Xu HH, Wang WQ, Li N, Wang WP, Lu Z, Møller IM, Song SQ. Identification of embryo proteins associated with seed germination and seedling establishment in germinating rice seeds. JOURNAL OF PLANT PHYSIOLOGY 2016; 196-197:79-92. [PMID: 27085178 DOI: 10.1016/j.jplph.2016.02.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 02/06/2016] [Accepted: 02/16/2016] [Indexed: 06/05/2023]
Abstract
Seed germination is a critical phase in the plant life cycle, but the mechanism of seed germination is still poorly understood. In the present study, rice (Oryza sativa L. cv. Peiai 64S) seeds were sampled individually when they reached different germination stages, quiescent, germinated sensu stricto, germinated completely and seedling, and were used to study the changes in the embryo proteome. A total of 88 protein spots showed a significant change in abundance during germination in water, and the results showed an activation of metabolic processes. Cell division, cell wall synthesis, and secondary metabolism were activated at late seed germination and during preparation for subsequent seedling establishment. Cycloheximide (CHX) at 70μM inhibited seedling establishment without an apparent negative effect on seed germination, while CHX at 500μM completely blocked seed germination. We used this observation to identify the potentially important proteins involved in seed germination (coleoptile protrusion) and seedling establishment (coleoptile and radicle protrusion). Twenty-six protein spots, mainly associated with sugar/polysaccharide metabolism and energy production, showed a significant difference in abundance during seed germination. Forty-nine protein spots, mainly involved in cell wall biosynthesis, proteolysis as well as cell defense and rescue, were required for seedling establishment. The results help improve our understanding of the key events (proteins) involved in germination and seedling development.
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Affiliation(s)
- Shu-Jun Liu
- Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Heng-Heng Xu
- Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Wei-Qing Wang
- Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ni Li
- Hunan Hybrid Rice Research Center/State Key Laboratory of Hybrid Rice, Changsha 410125, China
| | - Wei-Ping Wang
- Hunan Hybrid Rice Research Center/State Key Laboratory of Hybrid Rice, Changsha 410125, China
| | - Zhuang Lu
- Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ian Max Møller
- Department of Molecular Biology and Genetics, Aarhus University, Flakkebjerg, Slagelse, DK-4200, Denmark
| | - Song-Quan Song
- Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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21
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ahg12 is a dominant proteasome mutant that affects multiple regulatory systems for germination of Arabidopsis. Sci Rep 2016; 6:25351. [PMID: 27139926 PMCID: PMC4853794 DOI: 10.1038/srep25351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/14/2016] [Indexed: 11/15/2022] Open
Abstract
The ubiquitin-proteasome system is fundamentally involved in myriad biological phenomena of eukaryotes. In plants, this regulated protein degradation system has a pivotal role in the cellular response mechanisms for both internal and external stimuli, such as plant hormones and environmental stresses. Information about substrate selection by the ubiquitination machinery has accumulated, but there is very little information about selectivity for substrates at the proteasome. Here, we report characterization of a novel abscisic acid (ABA)-hypersensitive mutant named ABA hypersensitive germination12 (ahg12) in Arabidopsis. The ahg12 mutant showed a unique pleiotropic phenotype, including hypersensitivity to ABA and ethylene, and hyposensitivity to light. Map-based cloning identified the ahg12 mutation to cause an amino acid conversion in the L23 loop of RPT5a, which is predicted to form the pore structure of the 19S RP complex of the proteasome. Transient expression assays demonstrated that some plant-specific signaling components accumulated at higher levels in the ahg12 mutant. These results suggest that the ahg12 mutation led to changes in the substrate preference of the 26S proteasome. The discovery of the ahg12 mutation thus will contribute to elucidate the characteristics of the regulated protein degradation system.
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22
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Yang BJ, Han XX, Yin LL, Xing MQ, Xu ZH, Xue HW. Arabidopsis PROTEASOME REGULATOR1 is required for auxin-mediated suppression of proteasome activity and regulates auxin signalling. Nat Commun 2016; 7:11388. [PMID: 27109828 PMCID: PMC4848511 DOI: 10.1038/ncomms11388] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 03/21/2016] [Indexed: 01/14/2023] Open
Abstract
The plant hormone auxin is perceived by the nuclear F-box protein TIR1 receptor family and regulates gene expression through degradation of Aux/IAA transcriptional repressors. Several studies have revealed the importance of the proteasome in auxin signalling, but details on how the proteolytic machinery is regulated and how this relates to degradation of Aux/IAA proteins remains unclear. Here we show that an Arabidopsis homologue of the proteasome inhibitor PI31, which we name PROTEASOME REGULATOR1 (PTRE1), is a positive regulator of the 26S proteasome. Loss-of-function ptre1 mutants are insensitive to auxin-mediated suppression of proteasome activity, show diminished auxin-induced degradation of Aux/IAA proteins and display auxin-related phenotypes. We found that auxin alters the subcellular localization of PTRE1, suggesting this may be part of the mechanism by which it reduces proteasome activity. Based on these results, we propose that auxin regulates proteasome activity via PTRE1 to fine-tune the homoeostasis of Aux/IAA repressor proteins thus modifying auxin activity. Plant responses to auxin require proteasome-mediated degradation of Aux/IAA transcriptional repressor proteins. Here, Yang et al. show that auxin suppresses proteasome activity in a manner dependent on the proteasome regulator PTRE1 and propose a mechanism for fine tuning Aux/IAA homoeostasis.
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Affiliation(s)
- Bao-Jun Yang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese academy of Sciences, Shanghai 200032, People's Republic of China
| | - Xin-Xin Han
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese academy of Sciences, Shanghai 200032, People's Republic of China
| | - Lin-Lin Yin
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese academy of Sciences, Shanghai 200032, People's Republic of China
| | - Mei-Qing Xing
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese academy of Sciences, Shanghai 200032, People's Republic of China
| | - Zhi-Hong Xu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese academy of Sciences, Shanghai 200032, People's Republic of China
| | - Hong-Wei Xue
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese academy of Sciences, Shanghai 200032, People's Republic of China
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PP2A-3 interacts with ACR4 and regulates formative cell division in the Arabidopsis root. Proc Natl Acad Sci U S A 2016; 113:1447-52. [PMID: 26792519 DOI: 10.1073/pnas.1525122113] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In plants, the generation of new cell types and tissues depends on coordinated and oriented formative cell divisions. The plasma membrane-localized receptor kinase ARABIDOPSIS CRINKLY 4 (ACR4) is part of a mechanism controlling formative cell divisions in the Arabidopsis root. Despite its important role in plant development, very little is known about the molecular mechanism with which ACR4 is affiliated and its network of interactions. Here, we used various complementary proteomic approaches to identify ACR4-interacting protein candidates that are likely regulators of formative cell divisions and that could pave the way to unraveling the molecular basis behind ACR4-mediated signaling. We identified PROTEIN PHOSPHATASE 2A-3 (PP2A-3), a catalytic subunit of PP2A holoenzymes, as a previously unidentified regulator of formative cell divisions and as one of the first described substrates of ACR4. Our in vitro data argue for the existence of a tight posttranslational regulation in the associated biochemical network through reciprocal regulation between ACR4 and PP2A-3 at the phosphorylation level.
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24
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Natural alleles of a proteasome α2 subunit gene contribute to thermotolerance and adaptation of African rice. Nat Genet 2015; 47:827-33. [DOI: 10.1038/ng.3305] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 04/22/2015] [Indexed: 12/21/2022]
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Polyn S, Willems A, De Veylder L. Cell cycle entry, maintenance, and exit during plant development. CURRENT OPINION IN PLANT BIOLOGY 2015; 23:1-7. [PMID: 25449720 DOI: 10.1016/j.pbi.2014.09.012] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 09/22/2014] [Accepted: 09/30/2014] [Indexed: 05/24/2023]
Abstract
Growth and development of plants are driven by the continuous production of new cells at the meristems; hence, it is of pivotal importance for plants to precisely regulate the timing and extent of cell proliferation. Although over the past decades the molecular components underlying cell cycle progression have been the subject of intensive research, knowledge remains scarce on how the various elements connect with developmental pathways. Recently, advances have been made that link cell cycle entry with nutrient availability, cell division maintenance with stem cell organization, and cell cycle exit with reactive oxygen species and developmental programs.
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Affiliation(s)
- Stefanie Polyn
- Department of Plant Systems Biology, VIB, B-9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium
| | - Alex Willems
- Department of Plant Systems Biology, VIB, B-9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium
| | - Lieven De Veylder
- Department of Plant Systems Biology, VIB, B-9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium.
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26
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Eshraghi L, Anderson JP, Aryamanesh N, McComb JA, Shearer B, Hardy GSJE. Suppression of the auxin response pathway enhances susceptibility to Phytophthora cinnamomi while phosphite-mediated resistance stimulates the auxin signalling pathway. BMC PLANT BIOLOGY 2014; 14:68. [PMID: 24649892 PMCID: PMC3999932 DOI: 10.1186/1471-2229-14-68] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 03/14/2014] [Indexed: 05/04/2023]
Abstract
BACKGROUND Phytophthora cinnamomi is a devastating pathogen worldwide and phosphite (Phi), an analogue of phosphate (Pi) is highly effective in the control of this pathogen. Phi also interferes with Pi starvation responses (PSR), of which auxin signalling is an integral component. In the current study, the involvement of Pi and the auxin signalling pathways in host and Phi-mediated resistance to P. cinnamomi was investigated by screening the Arabidopsis thaliana ecotype Col-0 and several mutants defective in PSR and the auxin response pathway for their susceptibility to this pathogen. The response to Phi treatment was also studied by monitoring its effect on Pi- and the auxin response pathways. RESULTS Here we demonstrate that phr1-1 (phosphate starvation response 1), a mutant defective in response to Pi starvation was highly susceptible to P. cinnamomi compared to the parental background Col-0. Furthermore, the analysis of the Arabidopsis tir1-1 (transport inhibitor response 1) mutant, deficient in the auxin-stimulated SCF (Skp1 - Cullin - F-Box) ubiquitination pathway was also highly susceptible to P. cinnamomi and the susceptibility of the mutants rpn10 and pbe1 further supported a role for the 26S proteasome in resistance to P. cinnamomi. The role of auxin was also supported by a significant (P < 0.001) increase in susceptibility of blue lupin (Lupinus angustifolius) to P. cinnamomi following treatment with the inhibitor of auxin transport, TIBA (2,3,5-triiodobenzoic acid). Given the apparent involvement of auxin and PSR signalling in the resistance to P. cinnamomi, the possible involvement of these pathways in Phi mediated resistance was also investigated. Phi (especially at high concentrations) attenuates the response of some Pi starvation inducible genes such as AT4, AtACP5 and AtPT2 in Pi starved plants. However, Phi enhanced the transcript levels of PHR1 and the auxin responsive genes (AUX1, AXR1and AXR2), suppressed the primary root elongation, and increased root hair formation in plants with sufficient Pi. CONCLUSIONS The auxin response pathway, particularly auxin sensitivity and transport, plays an important role in resistance to P. cinnamomi in Arabidopsis, and phosphite-mediated resistance may in some part be through its effect on the stimulation of the PSR and auxin response pathways.
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Affiliation(s)
- Leila Eshraghi
- Centre for Phytophthora Science and Management, School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, WA 6150, Australia
| | - Jonathan P Anderson
- CSIRO Plant Industry, Centre for Environment and Life Sciences, Private Bag 5, Wembley, WA 6913, Australia
- The University of Western Australia, Institute of Agriculture, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Nader Aryamanesh
- School of Plant Biology, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
- The University of Western Australia, Institute of Agriculture, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Jen A McComb
- Centre for Phytophthora Science and Management, School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, WA 6150, Australia
| | - Bryan Shearer
- Centre for Phytophthora Science and Management, School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, WA 6150, Australia
- Science Division, Department of Environment and conservation, Kensington, WA 6983, Australia
| | - Giles St J E Hardy
- Centre for Phytophthora Science and Management, School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, WA 6150, Australia
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Kurepa J, Li Y, Smalle JA. Reversion of the Arabidopsis rpn12a-1 exon-trap mutation by an intragenic suppressor that weakens the chimeric 5' splice site. F1000Res 2013; 2:60. [PMID: 24358894 PMCID: PMC3829128 DOI: 10.12688/f1000research.2-60.v2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/10/2013] [Indexed: 12/01/2022] Open
Abstract
Background: In the
Arabidopsis 26S proteasome mutant
rpn12a-1, an exon-trap T-DNA is inserted 531 base pairs downstream of the
RPN12a STOP codon. We have previously shown that this insertion activates a STOP codon-associated latent 5' splice site that competes with the polyadenylation signal during processing of the pre-mRNA. As a result of this dual input from splicing and polyadenylation in the
rpn12a-1 mutant, two
RPN12a transcripts are produced and they encode the wild-type RPN12a and a chimeric RPN12a-NPTII protein. Both proteins form complexes with other proteasome subunits leading to the formation of wild-type and mutant proteasome versions. The net result of this heterogeneity of proteasome particles is a reduction of total cellular proteasome activity. One of the consequences of reduced proteasomal activity is decreased sensitivity to the major plant hormone cytokinin. Methods: We performed ethyl methanesulfonate mutagenesis of
rpn12a-1 and isolated revertants with wild-type cytokinin sensitivity. Results: We describe the isolation and analyses of suppressor of
rpn12a-1 (
sor1). The
sor1 mutation is intragenic and located at the fifth position of the chimeric intron. This mutation weakens the activated 5' splice site associated with the STOP codon and tilts the processing of the
RPN12a mRNA back towards polyadenylation. Conclusions: These results validate our earlier interpretation of the unusual nature of the
rpn12a-1 mutation. Furthermore, the data show that optimal 26S proteasome activity requires RPN12a accumulation beyond a critical threshold. Finally, this finding reinforces our previous conclusion that proteasome function is critical for the cytokinin-dependent regulation of plant growth.
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Affiliation(s)
- Jasmina Kurepa
- Plant Physiology, Biochemistry, Molecular Biology Program, Department of Plant and Soil Sciences, University of Kentucky, Kentucky, 40546, USA
| | - Yan Li
- Plant Physiology, Biochemistry, Molecular Biology Program, Department of Plant and Soil Sciences, University of Kentucky, Kentucky, 40546, USA
| | - Jan A Smalle
- Plant Physiology, Biochemistry, Molecular Biology Program, Department of Plant and Soil Sciences, University of Kentucky, Kentucky, 40546, USA
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Seago JL, Fernando DD. Anatomical aspects of angiosperm root evolution. ANNALS OF BOTANY 2013; 112:223-38. [PMID: 23299993 PMCID: PMC3698381 DOI: 10.1093/aob/mcs266] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 11/09/2012] [Indexed: 05/19/2023]
Abstract
BACKGROUND AND AIMS Anatomy had been one of the foundations in our understanding of plant evolutionary trends and, although recent evo-devo concepts are mostly based on molecular genetics, classical structural information remains useful as ever. Of the various plant organs, the roots have been the least studied, primarily because of the difficulty in obtaining materials, particularly from large woody species. Therefore, this review aims to provide an overview of the information that has accumulated on the anatomy of angiosperm roots and to present possible evolutionary trends between representatives of the major angiosperm clades. SCOPE This review covers an overview of the various aspects of the evolutionary origin of the root. The results and discussion focus on angiosperm root anatomy and evolution covering representatives from basal angiosperms, magnoliids, monocots and eudicots. We use information from the literature as well as new data from our own research. KEY FINDINGS The organization of the root apical meristem (RAM) of Nymphaeales allows for the ground meristem and protoderm to be derived from the same group of initials, similar to those of the monocots, whereas in Amborellales, magnoliids and eudicots, it is their protoderm and lateral rootcap which are derived from the same group of initials. Most members of Nymphaeales are similar to monocots in having ephemeral primary roots and so adventitious roots predominate, whereas Amborellales, Austrobaileyales, magnoliids and eudicots are generally characterized by having primary roots that give rise to a taproot system. Nymphaeales and monocots often have polyarch (heptarch or more) steles, whereas the rest of the basal angiosperms, magnoliids and eudicots usually have diarch to hexarch steles. CONCLUSIONS Angiosperms exhibit highly varied structural patterns in RAM organization; cortex, epidermis and rootcap origins; and stele patterns. Generally, however, Amborellales, magnoliids and, possibly, Austrobaileyales are more similar to eudicots, and the Nymphaeales are strongly structurally associated with the monocots, especially the Acorales.
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Affiliation(s)
- James L Seago
- Department of Biological Sciences, SUNY at Oswego, Oswego, NY 13126, USA.
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29
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Di Giacomo E, Serino G, Frugis G. Emerging role of the ubiquitin proteasome system in the control of shoot apical meristem function(f). JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:7-20. [PMID: 23164365 DOI: 10.1111/jipb.12010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The shoot apical meristem (SAM) is a population of undifferentiated cells at the tip of the shoot axis that establishes early during plant embryogenesis and gives rise to all shoot organs throughout the plant's life. A plethora of different families of transcription factors (TFs) play a key role in establishing the equilibrium between cell differentiation and stem cell maintenance in the SAM. Fine tuning of these regulatory proteins is crucial for a proper and fast SAM response to environmental and hormonal cues, and for development progression. One effective way to rapidly inactivate TFs involves regulated proteolysis by the ubiquitin/26S proteasome system (UPS). However, a possible role of UPS-dependent protein degradation in the regulation of key SAM TFs has not been thoroughly investigated. Here, we summarize recent evidence supporting a role for the UPS in SAM maintenance and function. We integrate this survey with an in silico analysis of publicly-available microarray databases which identified ubiquitin ligases that are expressed in specific areas within the SAM, suggesting that they may regulate or act downstream of meristem-specific factors.
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Affiliation(s)
- Elisabetta Di Giacomo
- Istituto di Biologia e Biotecnologia Agraria, UOS Roma, Consiglio Nazionale delle Ricerche, Monterotondo Scalo, Roma 00015, Italy
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Different degree in proteasome malfunction has various effects on root growth possibly through preventing cell division and promoting autophagic vacuolization. PLoS One 2012; 7:e45673. [PMID: 23029176 PMCID: PMC3448697 DOI: 10.1371/journal.pone.0045673] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 08/20/2012] [Indexed: 01/07/2023] Open
Abstract
The ubiquitin/proteasome pathway plays a vital role in plant development. But the effects of proteasome malfunction on root growth, and the mechanism underlying this involvement remains unclear. In the present study, the effects of proteasome inhibitors on Arabidopsis root growth were studied through the analysis of the root length, and meristem size and cell length in maturation zone using FM4-64, and cell-division potential using GFP fusion cyclin B, and accumulation of ubiquitinated proteins using immunofluorescence labeling, and autophagy activity using LysoTracker and MDC. The results indicated that lower concentration of proteasome inhibitors promoted root growth, whereas higher concentration of inhibitors had the opposite effects. The accumulation of cyclin B was linked to MG132-induced decline in meristem size, indicating that proteasome malfunction prevented cell division. Besides, MG132-induced accumulation of the ubiquitinated proteins was associated with the increasing fluorescence signal of LysoTracker and MDC in the elongation zone, revealing a link between the activation of autophagy and proteasome malfunction. These results suggest that weak proteasome malfunction activates moderate autophagy and promotes cell elongation, which compensates the inhibitor-induced reduction of cell division, resulting in long roots. Whereas strong proteasome malfunction induces severe autophagy and disturbs cell elongation, resulting in short roots.
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Lyzenga WJ, Stone SL. Abiotic stress tolerance mediated by protein ubiquitination. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:599-616. [PMID: 22016431 DOI: 10.1093/jxb/err310] [Citation(s) in RCA: 257] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Plant growth and development is largely influenced by ubiquitin-mediated regulation of protein stability. Specificity of the ubiquitination pathway is controlled mainly by the substrate-recruiting E3 ubiquitin ligases, and consequently, E3 ligases control numerous cellular processes. Recent evidence that ubiquitination plays a critical role in regulating plant responses to abiotic stresses has launched intensive efforts to identify E3 ligases that mediate plant tolerance of adverse environmental conditions. Most stress-related E3 ligases identified to date facilitate responses to environmental stimuli by modulating the abundance of key downstream stress-responsive transcription factors. In this review, the regulatory roles of ubiquitin during the plant's response to abiotic stress are summarized and highlighted.
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Affiliation(s)
- Wendy J Lyzenga
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
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Hernández-Barrera A, Ugartechea-Chirino Y, Shishkova S, Napsucialy-Mendivil S, Soukup A, Reyes-Hernández BJ, Lira-Ruan V, Dong G, Dubrovsky JG. Apical meristem exhaustion during determinate primary root growth in the moots koom 1 mutant of Arabidopsis thaliana. PLANTA 2011; 234:1163-1177. [PMID: 21744091 DOI: 10.1007/s00425-011-1470-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 06/22/2011] [Indexed: 05/31/2023]
Abstract
An indeterminate developmental program allows plant organs to grow continuously by maintaining functional meristems over time. The molecular mechanisms involved in the maintenance of the root apical meristem are not completely understood. We have identified a new Arabidopsis thaliana mutant named moots koom 1 (mko1) that showed complete root apical meristem exhaustion of the primary root by 9 days post-germination. MKO1 is essential for maintenance of root cell proliferation. In the mutant, cell division is uncoupled from cell growth in the region corresponding to the root apical meristem. We established the sequence of cellular events that lead to meristem exhaustion in this mutant. Interestingly, the SCR and WOX5 promoters were active in the mko1 quiescent center at all developmental stages. However, during meristem exhaustion, the mutant root tip showed defects in starch accumulation in the columella and changes in auxin response pattern. Therefore, contrary to many described mutants, the determinate growth in mko1 seedlings does not appear to be a consequence of incorrect establishment or affected maintenance of the quiescent center but rather of cell proliferation defects both in stem cell niche and in the rest of the apical meristem. Our results support a model whereby the MKO1 gene plays an important role in the maintenance of the root apical meristem proliferative capacity and indeterminate root growth, which apparently acts independently of the SCR/SHR and WOX5 regulatory pathways.
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Affiliation(s)
- Alejandra Hernández-Barrera
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apartado Postal 510-3, 62250, Cuernavaca, Morelos, Mexico
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33
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Lee KH, Minami A, Marshall RS, Book AJ, Farmer LM, Walker JM, Vierstra RD. The RPT2 subunit of the 26S proteasome directs complex assembly, histone dynamics, and gametophyte and sporophyte development in Arabidopsis. THE PLANT CELL 2011; 23:4298-317. [PMID: 22158466 PMCID: PMC3269867 DOI: 10.1105/tpc.111.089482] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The regulatory particle (RP) of the 26S proteasome contains a heterohexameric ring of AAA-ATPases (RPT1-6) that unfolds and inserts substrates into the core protease (CP) for degradation. Through genetic analysis of the Arabidopsis thaliana gene pair encoding RPT2, we show that this subunit plays a critical role in 26S proteasome assembly, histone dynamics, and plant development. rpt2a rpt2b double null mutants are blocked in both male and female gamete transmission, demonstrating that the subunit is essential. Whereas rpt2b mutants are phenotypically normal, rpt2a mutants display a range of defects, including impaired leaf, root, trichome, and pollen development, delayed flowering, stem fasciation, hypersensitivity to mitomycin C and amino acid analogs, hyposensitivity to the proteasome inhibitor MG132, and decreased 26S complex stability. The rpt2a phenotype can be rescued by both RPT2a and RPT2b, indicative of functional redundancy, but not by RPT2a mutants altered in ATP binding/hydrolysis or missing the C-terminal hydrophobic sequence that docks the RPT ring onto the CP. Many rpt2a phenotypes are shared with mutants lacking the chromatin assembly factor complex CAF1. Like caf1 mutants, plants missing RPT2a or reduced in other RP subunits contain less histones, thus implicating RPT2 specifically, and the 26S proteasome generally, in plant nucleosome assembly.
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Ueda M, Matsui K, Ishiguro S, Kato T, Tabata S, Kobayashi M, Seki M, Shinozaki K, Okada K. Arabidopsis RPT2a encoding the 26S proteasome subunit is required for various aspects of root meristem maintenance, and regulates gametogenesis redundantly with its homolog, RPT2b. PLANT & CELL PHYSIOLOGY 2011; 52:1628-40. [PMID: 21784786 DOI: 10.1093/pcp/pcr093] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The 26S proteasome plays fundamental roles in the degradation of short-lived regulatory proteins, thereby controlling diverse cellular processes. In Arabidopsis, the essential RPT2 subunit is encoded by two highly homologous genes: RPT2a and RPT2b. Currently, only RPT2a has been reported to regulate various developmental processes, including the maintenance of the root apical meristem (RAM), although the roles of RPT2a in the RAM are still obscure. Here, we analyzed the cell type-specific requirement for RPT2a. When RPT2a was expressed locally in the rpt2a mutant, pleiotropic defects in the RAM, such as cell death and distorted cellular organization, were rescued differently, suggesting that RPT2a regulates various specific activities, which converge to maintain the RAM. On the other hand, the homologous RPT2b was also expressed in meristems, and the expression of RPT2b protein under the control of the RPT2a promoter complemented the rpt2a RAM defects, although the rpt2b mutant showed no obvious defect in all developmental aspects we examined. These results show that RPT2b might work in the RAM, but is dispensable for RAM maintenance in the presence of RPT2a. In contrast, the rpt2a rpt2b double mutant was lethal in male and female gametophytes, suggesting that RPT2a and RPT2b are redundantly required for gametogenesis. Furthermore, we showed that similar meristematic and gametophytic defects were caused by mutations in other subunit genes, RPT5a and RPT5b, suggesting that proper activity of the proteasome, not an RPT2-specific function, is required. Taken together, our results suggest that RPT2a and RPT2b contribute differently to the proteasome activity required for each developmental context.
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Affiliation(s)
- Minako Ueda
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, Japan
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Chung K, Tasaka M. RPT2a, a 26S proteasome AAA-ATPase, is Directly Involved in Arabidopsis CC-NBS-LRR Protein uni-1D-Induced Signaling Pathways. ACTA ACUST UNITED AC 2011; 52:1657-64. [DOI: 10.1093/pcp/pcr099] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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36
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Arabidopsis thaliana 26S proteasome subunits RPT2a and RPT5a are crucial for zinc deficiency-tolerance. Biosci Biotechnol Biochem 2011; 75:561-7. [PMID: 21389614 DOI: 10.1271/bbb.100794] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
RPTs (regulatory particle triple-A-ATPase) are components of 26S proteasome. We found novel roles of RPT2a and RPT5a in Zn deficiency-tolerance. Arabidopsis thaliana mutants carrying T-DNA in RPT2a and RPT5a were more sensitive to Zn deficiency than the wild-type. In the rpt mutants, the shoot Zn contents were similar to those of the wild-type. Transcripts of Zn deficiency-inducible genes were highly accumulated in the rpt mutants, suggesting that the rpt mutants suffer from various Zn deficiency symptoms, although the Zn levels are not reduced. Lipid peroxidation levels, known to be increased under Zn deficiency, were higher in the rpt mutants than in the wild-type. Poly-ubiquitinated proteins were accumulated upon exposure to Zn deficiency, especially in the rpt mutants. Overall, this study indicates that RPT2a and RPT5a are involved in Zn deficiency-tolerance, possibly through alleviation of oxidative stresses and/or processing of poly-ubiquitinated proteins.
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Zhang Z, Wang H, Luo D, Zeng M, Huang H, Cui X. Convergence of the 26S proteasome and the REVOLUTA pathways in regulating inflorescence and floral meristem functions in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:359-69. [PMID: 20797995 PMCID: PMC2993919 DOI: 10.1093/jxb/erq277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The 26S proteasome is a large multisubunit proteolytic complex, regulating growth and development in eukaryotes by selective removal of short-lived regulatory proteins. Here, it is shown that the 26S proteasome and the transcription factor gene REVOLUTA (REV) act together in maintaining inflorescence and floral meristem (IM and FM) functions. The characterization of a newly identified Arabidopsis mutant, designated ae4 (asymmetric leaves1/2 enhancer4), which carries a mutation in the gene encoding the 26S proteasome subunit, RPN2a, is reported. ae4 and rev have minor defects in phyllotaxy structure and meristem initiation, respectively, whereas ae4 rev demonstrated strong developmental defects. Compared with the rev single mutant, an increased percentage of ae4 rev plants exhibited abnormal vegetative shoot apical and axillary meristems. After flowering, ae4 rev first gave rise to a few normal-looking flowers, and then flowers with reduced numbers of all types of floral organs. In late reproductive development, instead of flowers, the ae4 rev IM produced numerous filamentous structures, which contained cells seen only in the floral organs, and then carpelloid organs. In situ hybridization revealed that expression of the WUSCHEL and CLAVATA3 genes was severely down-regulated or absent in the late appearing ae4 rev primordia, but the genes were strongly expressed in top-layer cells of inflorescence tips. Double mutant plants combining rev with other 26S proteasome subunit mutants, rpn1a and rpn9a, resembled ae4 rev, suggesting that the 26S proteasome might act as a whole in regulating IM and FM functions.
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Affiliation(s)
| | | | | | | | | | - Xiaofeng Cui
- To whom correspondence should be addressed. E-mail:
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38
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Sako K, Maki Y, Aoyama T, Goto DB, Yamaguchi J. Control of endoreduplication of trichome by RPT2a, a subunit of the 19S proteasome in Arabidopsis. JOURNAL OF PLANT RESEARCH 2010; 123:701-6. [PMID: 20195883 DOI: 10.1007/s10265-010-0321-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 01/10/2010] [Indexed: 05/17/2023]
Abstract
The ubiquitin/26S proteasome pathway plays a central role in the degradation of short-lived regulatory proteins to control many cellular events. The Arabidopsis knockout mutant rpt2a, which contains a defect in the AtRPT2a subunit of the 26S proteasome regulatory particle, showed enlarged leaves caused by increased cell size that correlated with increased ploidy caused by extended endoreduplication. To clarify the role of RPT2a in endoreduplication control, trichome development was genetically examined in further detail. RHL1 and GL3 encode proteins that have a role in the positive regulation of endocycle progression in trichomes. The rhl1 mutants are stalled at 8C and have trichomes with only a single branch. The rpt2a mutation did not alter the rhl1 mutant phenotype, and trichomes of double rpt2a rhl1 mutants resembled that of single rhl1 mutants. On the other hand, the rpt2a mutation suppressed the gl3 phenotype (stalled at 16C, two trichome branches), and trichomes of the double rpt2a gl3 mutant resembled those of the wild type (WT) plants. Together, these data suggest that RPT2a functions to negatively regulate endocycle progression following completion of the third endoreduplication step mediated by RHL1 (8C-16C).
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Affiliation(s)
- Kaori Sako
- Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku, Sapporo, Japan.
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Guyon-Debast A, Lécureuil A, Bonhomme S, Guerche P, Gallois JL. A SNP associated with alternative splicing of RPT5b causes unequal redundancy between RPT5a and RPT5b among Arabidopsis thaliana natural variation. BMC PLANT BIOLOGY 2010; 10:158. [PMID: 20682047 PMCID: PMC3017782 DOI: 10.1186/1471-2229-10-158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 08/03/2010] [Indexed: 05/04/2023]
Abstract
BACKGROUND The proteasome subunit RPT5, which is essential for gametophyte development, is encoded by two genes in Arabidopsis thaliana; RPT5a and RPT5b. We showed previously that RPT5a and RPT5b are fully redundant in the Columbia (Col-0) accession, whereas in the Wassilewskia accession (Ws-4), RPT5b does not complement the effect of a strong rpt5a mutation in the male gametophyte, and only partially complements rpt5a mutation in the sporophyte. RPT5bCol-0 and RPT5bWs-4 differ by only two SNPs, one located in the promoter and the other in the seventh intron of the gene. RESULTS By exploiting natural variation at RPT5b we determined that the SNP located in RPT5b intron seven, rather than the promoter SNP, is the sole basis of this lack of redundancy. In Ws-4 this SNP is predicted to create a new splicing branchpoint sequence that induces a partial mis-splicing of the pre-mRNA, leading to the introduction of a Premature Termination Codon. We characterized 5 accessions carrying this A-to-T substitution in intron seven and observed a complete correlation between this SNP and both a 10 to 20% level of the RPT5b pre-mRNA mis-splicing and the lack of ability to complement an rpt5a mutant phenotype. CONCLUSION The accession-dependent unequal redundancy between RPT5a and RPT5b genes illustrates an example of evolutionary drifting between duplicated genes through alternative splicing.
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Affiliation(s)
- Anouchka Guyon-Debast
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Versailles, France, F-78000 Versailles, France
| | - Alain Lécureuil
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Versailles, France, F-78000 Versailles, France
| | - Sandrine Bonhomme
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Versailles, France, F-78000 Versailles, France
| | - Philippe Guerche
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Versailles, France, F-78000 Versailles, France
| | - Jean-Luc Gallois
- Institut National de la Recherche Agronomique-UR1052 Station de Génétique et d'Amélioration des Fruits et Légumes, Domaine Saint Maurice, BP94, F84143, Montfavet, France
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Book AJ, Gladman NP, Lee SS, Scalf M, Smith LM, Vierstra RD. Affinity purification of the Arabidopsis 26 S proteasome reveals a diverse array of plant proteolytic complexes. J Biol Chem 2010; 285:25554-69. [PMID: 20516081 DOI: 10.1074/jbc.m110.136622] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Selective proteolysis in plants is largely mediated by the ubiquitin (Ub)/proteasome system in which substrates, marked by the covalent attachment of Ub, are degraded by the 26 S proteasome. The 26 S proteasome is composed of two subparticles, the 20 S core protease (CP) that compartmentalizes the protease active sites and the 19 S regulatory particle that recognizes and translocates appropriate substrates into the CP lumen for breakdown. Here, we describe an affinity method to rapidly purify epitope-tagged 26 S proteasomes intact from Arabidopsis thaliana. In-depth mass spectrometric analyses of preparations generated from young seedlings confirmed that the 2.5-MDa CP-regulatory particle complex is actually a heterogeneous set of particles assembled with paralogous pairs for most subunits. A number of these subunits are modified post-translationally by proteolytic processing, acetylation, and/or ubiquitylation. Several proteasome-associated proteins were also identified that likely assist in complex assembly and regulation. In addition, we detected a particle consisting of the CP capped by the single subunit PA200 activator that may be involved in Ub-independent protein breakdown. Taken together, it appears that a diverse and highly dynamic population of proteasomes is assembled in plants, which may expand the target specificity and functions of intracellular proteolysis.
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Affiliation(s)
- Adam J Book
- Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA
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De Tullio MC, Jiang K, Feldman LJ. Redox regulation of root apical meristem organization: connecting root development to its environment. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2010; 48:328-36. [PMID: 20031434 DOI: 10.1016/j.plaphy.2009.11.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 11/25/2009] [Accepted: 11/27/2009] [Indexed: 05/19/2023]
Abstract
Post-embryonic root growth relies on the proliferative activity of the root apical meristem (RAM), consisting, in part, of cells with juvenile characteristics (stem cells). It is generally, but erroneously held that the RAM indefinitely produces new cells throughout the lifespan of a plant, resulting in indeterminate root growth. On the contrary, convincing data, mainly from the lab of Thomas L. Rost, show in all species analyzed so far, including Arabidopsis, that RAM organization changes over time in parallel with both a cessation of the production of new cells, and a consequent reduction in root growth, even under optimal conditions. In addition, RAM organization evolved to become highly plastic and dynamic in response to environmental triggers (e.g. water and nutrient availability, pollutants). Under unfavourable conditions, the RAM is rapidly reorganized, and, as a result of the cessation of new cell production at the root tip, root growth is altered, and lateral root production is enhanced, thus providing the plant additional strategies to overcome the stress. It is now becoming increasingly clear that this environment-responsive developmental plasticity is linked to reactive oxygen/nitrogen species, antioxidants, and related enzymes, which form part of a complex signalling module specifically operating in the regulation of RAM functioning, in strict relationship with hormonal control of root development exerted by auxin, gibberellins and cytokinins. In turn, such redox/hormone crosstalk regulates gene expression.
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Affiliation(s)
- Mario C De Tullio
- Dipartimento di Biologia e Patologia Vegetale, Università di Bari, via Orabona 4, 70125 Bari, Italia.
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42
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Kurepa J, Karangwa C, Duke LS, Smalle JA. Arabidopsis sensitivity to protein synthesis inhibitors depends on 26S proteasome activity. PLANT CELL REPORTS 2010; 29:249-259. [PMID: 20087596 DOI: 10.1007/s00299-010-0818-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Revised: 01/03/2010] [Accepted: 01/07/2010] [Indexed: 05/28/2023]
Abstract
The 26S proteasome (26SP), the central protease of the ubiquitin-dependent proteolysis pathway, controls the regulated proteolysis of functional proteins and the removal of misfolded and damaged proteins. In Arabidopsis, cellular and stress response phenotypes of a number of mutants with partially impaired 26SP function have been reported. Here, we describe the responses of proteasome mutants to protein synthesis inhibitors. We show that the rpt2a-3, rpn10-1 and rpn12a-1 mutants are hypersensitive to the antibiotic hygromycin B, and tolerant to the translation inhibitor cycloheximide (CHX) and herbicide L-phosphinothricin (PPT). In addition to the novel mechanism for herbicide tolerance, our data suggests that the combination of hygromycin B, CHX and PPT growth-response assays could be used as a facile diagnostic tool to detect altered 26SP function in plant mutants and transgenic lines.
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Affiliation(s)
- Jasmina Kurepa
- Plant Physiology, Biochemistry, Molecular Biology Program, Department of Plant and Soil Sciences, College of Agriculture, University of Kentucky, 1401 University Drive, Lexington, KY 40546-0236, USA
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43
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Xu Y, Cao H, Chong K. APC-targeted RAA1 degradation mediates the cell cycle and root development in plants. PLANT SIGNALING & BEHAVIOR 2010; 5:218-23. [PMID: 20037474 PMCID: PMC2881264 DOI: 10.4161/psb.5.3.10661] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Protein degradation by the ubiquitin-proteasome system is necessary for a normal cell cycle. As compared with knowledge of the mechanism in animals and yeast, that in plants is less known. Here we summarize research into the regulatory mechanism of protein degradation in the cell cycle in plants. Anaphase-promoting complex/cyclosome (APC), in the E3 family of enzymes, plays an important role in maintaining normal mitosis. APC activation and substrate specificity is determined by its activators, which can recognize the destruction box (D-box) in APC target proteins. Oryza sativa root architecture-associated 1 (OsRAA1) with GTP-binding activity was originally cloned from rice. Overexpression of of OsRAA1 inhibits the growth of primary roots in rice. Knockdown lines showed reduced height of seedlings because of abnormal cell division. OsRAA1 transgenic rice and fission yeast show a higher proportion of metaphase cells than that of controls, which suggests a blocked transition from metaphase to anaphase during mitosis. OsRAA1 co-localizes with spindle tubulin. It contains the D-box motif and interacts with OsRPT4 of the regulatory particle of 26S proteasome. OsRAA1 may be a cell cycle inhibitor that can be degraded by the ubiquitin-proteasome system, and its disruption is necessary for the transition from metaphase to anaphase during root growth in rice.
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Affiliation(s)
- Yunyuan Xu
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
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44
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Hazak O, Bloch D, Poraty L, Sternberg H, Zhang J, Friml J, Yalovsky S. A rho scaffold integrates the secretory system with feedback mechanisms in regulation of auxin distribution. PLoS Biol 2010; 8:e1000282. [PMID: 20098722 PMCID: PMC2808208 DOI: 10.1371/journal.pbio.1000282] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Accepted: 12/09/2009] [Indexed: 11/30/2022] Open
Abstract
In plants, auxin distribution and tissue patterning are coordinated via a feedback loop involving the auxin-regulated cell polarity factor ICR1 and the secretory machinery. Development in multicellular organisms depends on the ability of individual cells to coordinate their behavior by means of small signaling molecules to form correctly patterned tissues. In plants, a unique mechanism of directional transport of the signaling molecule auxin between cells connects cell polarity and tissue patterning and thus is required for many aspects of plant development. Direction of auxin flow is determined by polar subcellular localization of PIN auxin efflux transporters. Dynamic PIN polar localization results from the constitutive endocytic cycling to and from the plasma membrane, but it is not well understood how this mechanism connects to regulators of cell polarity. The Rho family small GTPases ROPs/RACs are master regulators of cell polarity, however their role in regulating polar protein trafficking and polar auxin transport has not been established. Here, by analysis of mutants and transgenic plants, we show that the ROP interactor and polarity regulator scaffold protein ICR1 is required for recruitment of PIN proteins to the polar domains at the plasma membrane. icr1 mutant embryos and plants display an a array of severe developmental aberrations that are caused by compromised differential auxin distribution. ICR1 functions at the plasma membrane where it is required for exocytosis but does not recycle together with PINs. ICR1 expression is quickly induced by auxin but is suppressed at the positions of stable auxin maxima in the hypophysis and later in the embryonic and mature root meristems. Our results imply that ICR1 is part of an auxin regulated positive feedback loop realized by a unique integration of auxin-dependent transcriptional regulation into ROP-mediated modulation of cell polarity. Thus, ICR1 forms an auxin-modulated link between cell polarity, exocytosis, and auxin transport-dependent tissue patterning. The coordination of different cells during pattern formation is a fundamental process in the development of multicellular organisms. In plants, a unique mechanism of directional transport of the signaling molecule auxin between cells demonstrates the importance of cell polarity for tissue patterning. The direction of auxin flow is determined by polar subcellular localization of auxin transport proteins called PINs, which facilitate auxin efflux. At the same time, an auxin-mediated positive feedback mechanism reinforces the polar distribution of PINs. However, the molecular mechanisms that underlie polar PIN localization are not well understood. In eukaryotic cells, the Rho family of small GTPases function as central regulators of cell polarity. We show that a Rho-interacting protein from plants, called ICR1, is required for recruitment via the secretory system of PIN proteins to polar domains in the cell membrane. As a result, ICR1 is required for directional auxin transport and distribution and thereby for proper pattern formation. In addition, both the expression and subcellular localization of ICR1 are regulated by auxin, suggesting that ICR1 could function in a positive feedback loop that reinforces auxin distribution. Thus, ICR1 forms an auxin-modulated link between cell polarity, protein secretion, and auxin-dependent tissue patterning.
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Affiliation(s)
- Ora Hazak
- Department of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Daria Bloch
- Department of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Limor Poraty
- Department of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Hasana Sternberg
- Department of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Jing Zhang
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, Ghent, Belgium
| | - Jiří Friml
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, Ghent, Belgium
| | - Shaul Yalovsky
- Department of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
- * E-mail:
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45
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Huang L, Yang S, Zhang S, Liu M, Lai J, Qi Y, Shi S, Wang J, Wang Y, Xie Q, Yang C. The Arabidopsis SUMO E3 ligase AtMMS21, a homologue of NSE2/MMS21, regulates cell proliferation in the root. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 60:666-78. [PMID: 19682286 DOI: 10.1111/j.1365-313x.2009.03992.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
hMMS21 is a SUMO E3 ligase required for the prevention of DNA damage-induced apoptosis, and acts by facilitating DNA repair in human cells. The Arabidopsis genome contains a putative MMS21 homologue capable of interacting with the SUMO E2 conjugating enzyme AtSCE1a, as indicated by a yeast two-hybrid screen and bimolecular fluorescence complementation experiments. In vitro and in vivo data demonstrated that AtMMS21 was a SUMO E3 ligase. We identified the Arabidopsis AtMMS21 null T-DNA insertion mutant mms21-1, which had a short-root phenotype, and affected cell proliferation in the apical root meristem, as indicated by impaired expression of the cell division marker CYCB1:GUS in mms21-1 roots. The mms21-1 roots had reduced responses to exogenous cytokinins, and decreased expression of the cytokinin-induced genes ARR3, ARR4, ARR5 and ARR7, compared with the wild type. Thus, our findings suggest that the AtMMS21 gene is involved in root development via cell-cycle regulation and cytokinin signalling.
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Affiliation(s)
- Lixia Huang
- Guangdong Key Lab of Biotechnology for Plant Development, College of Life Science, South China Normal University, Guangzhou 510631, China
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46
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Kurepa J, Wang S, Li Y, Smalle J. Proteasome regulation, plant growth and stress tolerance. PLANT SIGNALING & BEHAVIOR 2009; 4:924-7. [PMID: 19826220 PMCID: PMC2801354 DOI: 10.4161/psb.4.10.9469] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Accepted: 06/29/2009] [Indexed: 05/19/2023]
Abstract
Plant cells contain a mixture of 26S and 20S proteasomes that mediate ubiquitin-dependent and ubiquitin-independent proteolysis, respectively. The 26S proteasome contains the 20S proteasome and one or two regulatory particles that are required for ubiquitin-dependent degradation. Comparative analyses of Arabidopsis proteasome mutants revealed that a decrease in 26S proteasome biogenesis causes heat shock hypersensitivity and reduced cell division rates that are compensated by increased cell expansion. Loss of 26S proteasome function also leads to an increased 20S proteasome biogenesis, which in turn enhances the cellular capacity to degrade oxidized proteins and thus increases oxidative stress tolerance. These findings suggest the intriguing possibility that 26S and 20S proteasome activities are regulated to control plant development and stress responses. This mini-review highlights some of the recent studies on proteasome regulation in plants.
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Affiliation(s)
- Jasmina Kurepa
- Plant Physiology, Biochemistry, Molecular Biology Program, Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
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47
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Sonoda Y, Sako K, Maki Y, Yamazaki N, Yamamoto H, Ikeda A, Yamaguchi J. Regulation of leaf organ size by the Arabidopsis RPT2a 19S proteasome subunit. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 60:68-78. [PMID: 19500299 DOI: 10.1111/j.1365-313x.2009.03932.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The ubiquitin/26S proteasome pathway plays a central role in the degradation of short-lived regulatory proteins, to control many cellular events. To further understand this pathway, we focused on the RPT2 subunit of the 26S proteasome regulatory particle. The Arabidopsis genome contains two genes, AtRPT2a and AtRPT2b, which encode paralog molecules of the RPT2 subunit, with a difference of only three amino acids in the protein sequences. Both genes showed similar mRNA accumulation patterns. However, the rpt2a mutant showed a specific phenotype of enlarged leaves caused by increased cell size, in correlation with increased ploidy. Detailed analyses revealed that cell expansion is increased in the rpt2a mutant by extended endoreduplication early in leaf development. The transcription of genes encoding cell cycle-related components, for DNA replication licensing and the G2/M phase, was also promoted in the rpt2a mutant, suggesting that extended endoreduplication was caused by increased DNA replication, and disrupted regulation of the G2/M checkpoint, at the proliferation stage of leaf development.
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Affiliation(s)
- Yutaka Sonoda
- Faculty of Advanced Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan
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48
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Tromas A, Braun N, Muller P, Khodus T, Paponov IA, Palme K, Ljung K, Lee JY, Benfey P, Murray JAH, Scheres B, Perrot-Rechenmann C. The AUXIN BINDING PROTEIN 1 is required for differential auxin responses mediating root growth. PLoS One 2009; 4:e6648. [PMID: 19777056 PMCID: PMC2744284 DOI: 10.1371/journal.pone.0006648] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 07/13/2009] [Indexed: 12/18/2022] Open
Abstract
Background In plants, the phytohormone auxin is a crucial regulator sustaining growth and development. At the cellular level, auxin is interpreted differentially in a tissue- and dose-dependent manner. Mechanisms of auxin signalling are partially unknown and the contribution of the AUXIN BINDING PROTEIN 1 (ABP1) as an auxin receptor is still a matter of debate. Methodology/Principal Findings Here we took advantage of the present knowledge of the root biological system to demonstrate that ABP1 is required for auxin response. The use of conditional ABP1 defective plants reveals that the protein is essential for maintenance of the root meristem and acts at least on the D-type CYCLIN/RETINOBLASTOMA pathway to control entry into the cell cycle. ABP1 affects PLETHORA gradients and confers auxin sensitivity to root cells thus defining the competence of the cells to be maintained within the meristem or to elongate. ABP1 is also implicated in the regulation of gene expression in response to auxin. Conclusions/Significance Our data support that ABP1 is a key regulator for root growth and is required for auxin-mediated responses. Differential effects of ABP1 on various auxin responses support a model in which ABP1 is the major regulator for auxin action on the cell cycle and regulates auxin-mediated gene expression and cell elongation in addition to the already well known TIR1-mediated ubiquitination pathway.
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Affiliation(s)
- Alexandre Tromas
- Institut des Sciences du Végétal, CNRS UPR2355, Université Paris Sud Orsay, Gif sur Yvette, France
| | - Nils Braun
- Institut des Sciences du Végétal, CNRS UPR2355, Université Paris Sud Orsay, Gif sur Yvette, France
- Institute of Biotechnology, University of Cambridge, Cambridge, United Kingdom
| | - Philippe Muller
- Institut des Sciences du Végétal, CNRS UPR2355, Université Paris Sud Orsay, Gif sur Yvette, France
| | - Tatyana Khodus
- Institut für Biology II – Zellbiologie Universität Freiburg, Freiburg, Germany
| | - Ivan A. Paponov
- Institut für Biology II – Zellbiologie Universität Freiburg, Freiburg, Germany
| | - Klaus Palme
- Institut für Biology II – Zellbiologie Universität Freiburg, Freiburg, Germany
| | - Karin Ljung
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Sveriges Lantbruksuniversitet, Umeå, Sweden
| | - Ji-Young Lee
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Philip Benfey
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - James A. H. Murray
- Institute of Biotechnology, University of Cambridge, Cambridge, United Kingdom
| | - Ben Scheres
- Department of Molecular Cell Biology, Utrecht University, Utrecht, The Netherlands
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Brenner ED, Feinberg P, Runko S, Coruzzi GM. A mutation in the Proteosomal Regulatory Particle AAA-ATPase-3 in Arabidopsis impairs the light-specific hypocotyl elongation response elicited by a glutamate receptor agonist, BMAA. PLANT MOLECULAR BIOLOGY 2009; 70:523-533. [PMID: 19412571 DOI: 10.1007/s11103-009-9489-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Accepted: 04/03/2009] [Indexed: 05/27/2023]
Abstract
BMAA is a cycad-derived glutamate receptor agonist that causes a two- to three-fold increase in hypocotyl elongation on Arabidopsis seedlings grown in the light. To probe the role of plant glutamate receptors and their downstream mediators, we utilized a previously described genetic screen to identify a novel, BMAA insensitive morphology (bim) mutant, bim409. The normal BMAA-induced hypocotyl elongation response observed on wild-type seedlings grown in the light is impaired in the bim409 mutant. This BMAA-induced phenotype is light-specific, as the bim409 mutant exhibits normal hypocotyl elongation in etiolated (dark grown) plants (+ or - BMAA). The mutation in bim409 was identified to be in a gene encoding the Proteosomal Regulatory Particle AAA-ATPase-3 (RPT3). Possible roles of the proteosome in Glu-mediated signaling in plants is discussed.
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Affiliation(s)
- Eric D Brenner
- The International Plant Science Center, The New York Botanical Garden, 200th and Kazimiroff Blvd., Bronx, NY 10458, USA.
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50
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Vierstra RD. The ubiquitin-26S proteasome system at the nexus of plant biology. Nat Rev Mol Cell Biol 2009; 10:385-97. [PMID: 19424292 DOI: 10.1038/nrm2688] [Citation(s) in RCA: 825] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Plants, like other eukaryotes, rely on proteolysis to control the abundance of key regulatory proteins and enzymes. Strikingly, genome-wide studies have revealed that the ubiquitin-26S proteasome system (UPS) in particular is an exceedingly large and complex route for protein removal, occupying nearly 6% of the Arabidopsis thaliana proteome. But why is the UPS so pervasive in plants? Data accumulated over the past few years now show that it targets numerous intracellular regulators that have central roles in hormone signalling, the regulation of chromatin structure and transcription, tailoring morphogenesis, responses to environmental challenges, self recognition and battling pathogens.
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Affiliation(s)
- Richard D Vierstra
- Department of Genetics, 425G Henry Mall, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
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