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Vogel K, Isono E. Deubiquitylating enzymes in Arabidopsis thaliana endocytic protein degradation. Biochem Soc Trans 2024; 52:291-299. [PMID: 38174770 DOI: 10.1042/bst20230561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024]
Abstract
The regulation of ubiquitylation is key for plant growth and development, in which the activities of ubiquitylating enzymes as well as deubiquitylating enzymes (DUBs) determine the stability or function of the modified proteins. In contrast with ubiquitylating enzymes, there are less numbers of DUBs. DUBs can be classified into seven protein families according to the amino acid sequence of their catalytic domains. The catalytic domains of animal and plant DUB families show high homology, whereas the regions outside of the catalytic site can vary a lot. By hydrolyzing the ubiquitin molecules from ubiquitylated proteins, DUBs control ubiquitin-dependent selective protein degradation pathways such as the proteasomal-, autophagic-, and endocytic degradation pathways. In the endocytic degradation pathway, DUBs can modulate the endocytic trafficking and thus the stability of plasma membrane proteins including receptors and transporters. To date, three DUB families were shown to control the endocytic degradation pathway namely associated molecule with the SH3 domain of STAM (AMSH) 3, ubiquitin-specific protease (UBP) 12 and UBP13, and ovarian tumor protease (OTU) 11 and OTU12. In this review we will summarize the activity, molecular functions, and target protein of these DUBs and how they contribute to the environmental response of plants.
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Affiliation(s)
- Karin Vogel
- Department of Biology, University of Konstanz, Universitätsstraße 10, D-78464 Konstanz, Germany
| | - Erika Isono
- Department of Biology, University of Konstanz, Universitätsstraße 10, D-78464 Konstanz, Germany
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2
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Yu Z, Sun X, Chen Z, Wang Q, Zhang C, Liu X, Wu W, Yin Y. Exploring the roles of ZmARM gene family in maize development and abiotic stress response. PeerJ 2023; 11:e16254. [PMID: 37920843 PMCID: PMC10619510 DOI: 10.7717/peerj.16254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 09/18/2023] [Indexed: 11/04/2023] Open
Abstract
Armadillo (ARM) was a gene family important to plants, with crucial roles in regulating plant growth, development, and stress responses. However, the properties and functions of ARM family members in maize had received limited attention. Therefore, this study employed bioinformatics methods to analyze the structure and evolution of ARM-repeat protein family members in maize. The maize (Zea mays L.) genome contains 56 ARM genes distributed over 10 chromosomes, and collinearity analysis indicated 12 pairs of linkage between them. Analysis of the physicochemical properties of ARM proteins showed that most of these proteins were acidic and hydrophilic. According to the number and evolutionary analysis of the ARM genes, the ARM genes in maize can be divided into eight subgroups, and the gene structure and conserved motifs showed similar compositions in each group. The findings shed light on the significant roles of 56 ZmARM domain genes in development and abiotic stress, particularly drought stress. RNA-Seq and qRT-PCR analysis revealed that drought stress exerts an influence on specific members of the ZmARM family, such as ZmARM4, ZmARM12, ZmARM34 and ZmARM36. The comprehensive profiling of these genes in the whole genome, combined with expression analysis, establishes a foundation for further exploration of plant gene function in the context of abiotic stress and reproductive development.
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Affiliation(s)
- Zhijia Yu
- College of Agriculture, Yanbian University, Jilin, China
- Jilin Academy of Agricultural Sciences, Institute of Agricultural Biotechnology, Changchun, China
| | - Xiaopeng Sun
- Huazhong Agricultural University, National Key Laboratory of Crop Genetic Improvement, Wuhan, China
| | - Ziqi Chen
- Jilin Academy of Agricultural Sciences, Institute of Agricultural Biotechnology, Changchun, China
| | - Qi Wang
- Jilin Academy of Agricultural Sciences, Institute of Agricultural Biotechnology, Changchun, China
| | - Chuang Zhang
- Jilin Academy of Agricultural Sciences, Institute of Agricultural Biotechnology, Changchun, China
| | - Xiangguo Liu
- College of Agriculture, Yanbian University, Jilin, China
- Jilin Academy of Agricultural Sciences, Institute of Agricultural Biotechnology, Changchun, China
| | - Weilin Wu
- College of Agriculture, Yanbian University, Jilin, China
| | - Yuejia Yin
- Jilin Academy of Agricultural Sciences, Institute of Agricultural Biotechnology, Changchun, China
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Zhang C, Wang W, Wang D, Hu S, Zhang Q, Wang Z, Cui L. Genome-Wide Identification and Characterization of the WRKY Gene Family in Scutellaria baicalensis Georgi under Diverse Abiotic Stress. Int J Mol Sci 2022; 23:ijms23084225. [PMID: 35457040 PMCID: PMC9029115 DOI: 10.3390/ijms23084225] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/04/2022] [Accepted: 04/07/2022] [Indexed: 02/06/2023] Open
Abstract
The WRKY gene family is an important inducible regulatory factor in plants, which has been extensively studied in many model plants. It has progressively become the focus of investigation for the secondary metabolites of medicinal plants. Currently, there is no systematic analysis of the WRKY gene family in Scutellaria baicalensis Georgi. For this study, a systematic and comprehensive bioinformatics analysis of the WRKY gene family was conducted based on the genomic data of S. baicalensis. A total of 77 WRKY members were identified and 75 were mapped onto nine chromosomes, respectively. Their encoded WRKY proteins could be classified into three subfamilies: Group I, Group II (II-a, II-b, II-c, II-d, II-e), and Group III, based on the characteristics of the amino acid sequences of the WRKY domain and genetic structure. Syntenic analysis revealed that there were 35 pairs of repetitive fragments. Furthermore, the transcriptome data of roots, stems, leaves, and flowers showed that the spatial expression profiles of WRKYs were different. qRT-PCR analysis revealed that 11 stress-related WRKYs exhibited specific expression patterns under diverse treatments. In addition, sub cellular localization analysis indicated that SbWRKY26 and SbWRKY41 were localized in nucleus. This study is the first to report the identification and characterization of the WRKY gene family in S. baicalensis, which is valuable for the further exploration of the biological function of SbWRKYs. It also provides valuable bioinformatics data for S. baicalensis and provides a reference for assessing the medicinal properties of the genus.
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Structural Features of a Full-Length Ubiquitin Ligase Responsible for the Formation of Patches at the Plasma Membrane. Int J Mol Sci 2021; 22:ijms22179455. [PMID: 34502365 PMCID: PMC8431560 DOI: 10.3390/ijms22179455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 08/22/2021] [Accepted: 08/27/2021] [Indexed: 11/28/2022] Open
Abstract
Plant U-box armadillo repeat (PUB-ARM) ubiquitin (Ub) ligases have important functions in plant defense through the ubiquitination of target proteins. Defense against pathogens involves vesicle trafficking and the formation of extracellular vesicles. The PUB-ARM protein SENESCENCE ASSOCIATED UBIQUITIN E3 LIGASE1 (SAUL1) can form patches at the plasma membrane related to tethering multi-vesicular bodies (MVBs) to the plasma membrane. We uncovered the structure of a full-length plant ubiquitin ligase and the structural requirements of SAUL1, which are crucial for its function in patch formation. We resolved the structure of SAUL1 monomers by small-angle X-ray scattering (SAXS). The SAUL1 model showed that SAUL1 consists of two domains: a domain containing the N-terminal U-box and armadillo (ARM) repeats and the C-terminal ARM repeat domain, which includes a positively charged groove. We showed that all C-terminal ARM repeats are essential for patch formation and that this function requires arginine residue at position 736. By applying SAXS to polydisperse SAUL1 systems, the oligomerization of SAUL1 is detectable, with SAUL1 tetramers being the most prominent oligomers at higher concentrations. The oligomerization domain consists of the N-terminal U-box and some N-terminal ARM repeats. Deleting the U-box resulted in the promotion of the SAUL1 tethering function. Our findings indicate that structural changes in SAUL1 may be fundamental to its function in forming patches at the plasma membrane.
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Genome-wide identification and expression analysis of U-box gene family in wild emmer wheat (Triticum turgidum L. ssp. dicoccoides). Gene 2021; 799:145840. [PMID: 34274467 DOI: 10.1016/j.gene.2021.145840] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 07/13/2021] [Indexed: 11/19/2022]
Abstract
In this study, 82 U-box genes were identified in wild emmer wheat (TdPUBs) through a genome-search method. Phylogenetic analysis classified them into seven groups and the genes belonging to the same group shared the similar exon-intron structure, motif organization and cis-element compositions. Synteny analysis of the U-box genes between different species revealed that segmental duplication and polyploidization mainly contributed to the expansion of TdPUBs. Furthermore, the genetic variations of U-box were investigated in wild emmer, domesticated emmer and durum wheat. Results showed that significant genetic bottleneck has occurred during domestication process of tetraploid emmer wheat. Meanwhile, 12 TdPUBs were co-located with known domestication related QTLs. Finally, the tissue-specific and stress-responsive TdPUB genes were identified through RNA-seq analysis. Combined with qPCR validation of 19 salt-responsive TdPUBs, the candidates involving in salt response were obtained. It lays the foundation to better understand the regulatory roles of U-box family in emmer wheat and beyond.
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Nan Y, Xie Y, Atif A, Wang X, Zhang Y, Tian H, Gao Y. Identification and Expression Analysis of SLAC/ SLAH Gene Family in Brassica napus L. Int J Mol Sci 2021; 22:ijms22094671. [PMID: 33925116 PMCID: PMC8125795 DOI: 10.3390/ijms22094671] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/16/2021] [Accepted: 04/21/2021] [Indexed: 12/21/2022] Open
Abstract
Slow type anion channels (SLAC/SLAHs) play important roles during anion transport, growth and development, abiotic stress responses and hormone responses in plants. However, there is few report on SLAC/SLAHs in rapeseed (Brassica napus). Genome-wide identification and expression analysis of SLAC/SLAH gene family members were performed in B. napus. A total of 23 SLAC/SLAH genes were identified in B. napus. Based on the structural characteristics and phylogenetic analysis of these members, the SLAC/SLAHs could be classified into three main groups. Transcriptome data demonstrated that BnSLAH3 genes were detected in various tissues of the rapeseed and could be up-regulated by low nitrate treatment in roots. BnSLAC/SLAHs were exclusively localized on the plasma membrane in transient expression of tobacco leaves. These results will increase our understanding of the evolution and expression of the SLAC/SLAHs and provide evidence for further research of biological functions of candidates in B. napus.
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Affiliation(s)
- Yunyou Nan
- College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China; (Y.N.); (Y.X.); (A.A.); (X.W.)
| | - Yuyu Xie
- College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China; (Y.N.); (Y.X.); (A.A.); (X.W.)
| | - Ayub Atif
- College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China; (Y.N.); (Y.X.); (A.A.); (X.W.)
| | - Xiaojun Wang
- College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China; (Y.N.); (Y.X.); (A.A.); (X.W.)
| | - Yanfeng Zhang
- Hybrid Rapeseed Research Center of Shaanxi Province, Yangling 712100, China;
| | - Hui Tian
- College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China; (Y.N.); (Y.X.); (A.A.); (X.W.)
- Correspondence: (H.T.); (Y.G.)
| | - Yajun Gao
- College of Natural Resource and Environment, Northwest A&F University, Yangling 712100, China; (Y.N.); (Y.X.); (A.A.); (X.W.)
- Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Yangling 712100, China
- Correspondence: (H.T.); (Y.G.)
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Wang N, Liu Y, Cai Y, Tang J, Li Y, Gai J. The soybean U-box gene GmPUB6 regulates drought tolerance in Arabidopsis thaliana. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 155:284-296. [PMID: 32795910 DOI: 10.1016/j.plaphy.2020.07.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 06/15/2020] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
The plant U-box (PUB) proteins function as E3 ligases to poly-ubiquitinate the target proteins for their degradation or post-translational modification. PUBs also play important roles in regulation of diverse biological processes, including plant response to environmental stresses. In this study, the functional characterization of a soybean PUB gene, GmPUB6, was performed. GmPUB6 was mainly localized to peroxisome, and showed E3 ubiquitin ligase activity. The transcript levels of GmPUB6 in soybean leaves and roots were induced by abscisic acid (ABA), high salinity and polyethylene glycol (PEG) treatment. Comparing with the wild-type (WT) plants, overexpression of GmPUB6 in Arabidopsis thaliana decreased plant survival rate after drought stress, reduced seed germination rate and root elongation under mannitol (osmotic) stress, and suppressed ABA- or mannitol-mediated stomatal closure. In addition, under dehydration stress, the relative expression levels of seven stress responsive genes, including ABI1, DREB2A, KIN2, RAB18, RD20, RD29A and RD29B, were lower in GmPUB6-overexpressed plants than WT. Taken together, these results suggest that GmPUB6 functions as a negative regulator in drought tolerance, and plays an important role in osmotic stress and ABA signaling pathways, which might be the possible mechanism of PUB6 participating in drought stress response.
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Affiliation(s)
- Ning Wang
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, National Center for Soybean Improvement, Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture), Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095, China; Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Yandang Liu
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, National Center for Soybean Improvement, Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture), Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yuanyuan Cai
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, National Center for Soybean Improvement, Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture), Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jiajun Tang
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, National Center for Soybean Improvement, Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture), Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yan Li
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, National Center for Soybean Improvement, Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture), Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Junyi Gai
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, National Center for Soybean Improvement, Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture), Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, 210095, China.
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Liu YC, Ma W, Niu JF, Li B, Zhou W, Liu S, Yan YP, Ma J, Wang ZZ. Systematic analysis of SmWD40s, and responding of SmWD40-170 to drought stress by regulation of ABA- and H 2O 2-induced stomal movement in Salvia miltiorrhiza bunge. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 153:131-140. [PMID: 32502715 DOI: 10.1016/j.plaphy.2020.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/28/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
WD40 proteins play crucial roles in response to abiotic stress. By screening the genome sequences of Salvia miltiorrhiza Bunge, 225 SmWD40 genes were identified and divided into 9 subfamilies (I-IX). Physiological, biochemical, gene structure, conserved protein motif and GO annotation analyses were performed on SmWD40 family members. The SmWD40-170 was found in 110 SmWD40 genes that contain drought response elements, SmWD40-170 was one of these genes whose response in terms of expression under drought was significant. The expression of SmWD40-170 was also up-regulated by ABA and H2O2. Through observed the stomatal phenotype of SmWD40-170 transgenic lines, the stomatal closure was abolished under dehydration, ABA and H2O2 treatment in SmWD40-170 knockdown lines. Abscisic acid (ABA), as the key phytohormone, elevates reactive oxygen species (ROS) levels under drought stress. The ABA-ROS interaction mediated the generation of H2O2 and the activation of anion channel in guard cells. The osmolality alteration of guard cells further accelerated the stomatal closure. As a second messenger, nitric oxide (NO) regulated ABA signaling, the NO stimulated protein kinase activity inhibited the K+ influx which result in stomatal closure. These NO-relevant events were essential for ABA-induced stomatal closure. The reduction of NO production was also observed in the guard cells of SmWD40-170 knockdown lines. The abolished of stomatal closure attributed to the SmWD40-170 deficiency induced the reduction of NO content. In general, the SmWD40-170 is a critical drought response gene in SmWD40 gene family and regulates ABA- and H2O2-induced stomatal movement by affecting the synthesis of NO.
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Affiliation(s)
- Yuan-Chu Liu
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China.
| | - Wen Ma
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China.
| | - Jun-Feng Niu
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China.
| | - Bin Li
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China.
| | - Wen Zhou
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China.
| | - Shuai Liu
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China.
| | - Ya-Ping Yan
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China.
| | - Ji Ma
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China.
| | - Zhe-Zhi Wang
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China.
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de Luxán-Hernández C, Lohmann J, Hellmeyer W, Seanpong S, Wöltje K, Magyar Z, Pettkó-Szandtner A, Pélissier T, De Jaeger G, Hoth S, Mathieu O, Weingartner M. PP7L is essential for MAIL1-mediated transposable element silencing and primary root growth. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:703-717. [PMID: 31849124 DOI: 10.1111/tpj.14655] [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: 03/21/2019] [Revised: 11/22/2019] [Accepted: 12/04/2019] [Indexed: 05/16/2023]
Abstract
The two paralogous Arabidopsis genes MAINTENANCE OF MERISTEMS (MAIN) and MAINTENANCE OF MERISTEMS LIKE1 (MAIL1) encode a conserved retrotransposon-related plant mobile domain and are known to be required for silencing of transposable elements (TE) and for primary root development. Loss of function of either MAIN or MAIL1 leads to release of heterochromatic TEs, reduced condensation of pericentromeric heterochromatin, cell death of meristem cells and growth arrest of the primary root soon after germination. Here, we show that they act in one protein complex that also contains the inactive isoform of PROTEIN PHOSPHATASE 7 (PP7), which is named PROTEIN PHOSPHATASE 7-LIKE (PP7L). PP7L was previously shown to be important for chloroplast biogenesis and efficient chloroplast protein synthesis. We show that loss of PP7L function leads to the same root growth phenotype as loss of MAIL1 or MAIN. In addition, pp7l mutants show similar silencing defects. Double mutant analyses confirmed that the three proteins act in the same molecular pathway. The primary root growth arrest, which is associated with cell death of stem cells and their daughter cells, is a consequence of genome instability. Our data demonstrate so far unrecognized functions of an inactive phosphatase isoform in a protein complex that is essential for silencing of heterochromatic elements and for maintenance of genome stability in dividing cells.
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Affiliation(s)
- Cloe de Luxán-Hernández
- Molecular Plant Physiology, Institute for Plant Science and Microbiology, Universität Hamburg, Hamburg, 22609, Germany
| | - Julia Lohmann
- Molecular Plant Physiology, Institute for Plant Science and Microbiology, Universität Hamburg, Hamburg, 22609, Germany
| | - Wiebke Hellmeyer
- Molecular Plant Physiology, Institute for Plant Science and Microbiology, Universität Hamburg, Hamburg, 22609, Germany
| | - Senoch Seanpong
- Molecular Plant Physiology, Institute for Plant Science and Microbiology, Universität Hamburg, Hamburg, 22609, Germany
| | - Kerstin Wöltje
- Molecular Plant Physiology, Institute for Plant Science and Microbiology, Universität Hamburg, Hamburg, 22609, Germany
| | - Zoltan Magyar
- Institute of Plant Biology, Biological Research Centre, Szeged, 6726, Hungary
| | - Aladár Pettkó-Szandtner
- Institute of Plant Biology, Biological Research Centre, Szeged, 6726, Hungary
- Laboratory of Proteomics Research, Biological Research Centre, Temesvári krt. 62, 6726, Szeged, Hungary
| | - Thierry Pélissier
- GReD - CNRS UMR6293 - Inserm U1103, Université Clermont Auvergne, UFR de Médecine, Clermont-Ferrand Cedex, France
| | - Geert De Jaeger
- VIB Center for Plant Systems Biology, 9052, Gent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052, Gent, Belgium
| | - Stefan Hoth
- Molecular Plant Physiology, Institute for Plant Science and Microbiology, Universität Hamburg, Hamburg, 22609, Germany
| | - Olivier Mathieu
- GReD - CNRS UMR6293 - Inserm U1103, Université Clermont Auvergne, UFR de Médecine, Clermont-Ferrand Cedex, France
| | - Magdalena Weingartner
- Molecular Plant Physiology, Institute for Plant Science and Microbiology, Universität Hamburg, Hamburg, 22609, Germany
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10
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Wang D, Liu H, Wang H, Zhang P, Shi C. A novel sucrose transporter gene IbSUT4 involves in plant growth and response to abiotic stress through the ABF-dependent ABA signaling pathway in Sweetpotato. BMC PLANT BIOLOGY 2020; 20:157. [PMID: 32293270 PMCID: PMC7157994 DOI: 10.1186/s12870-020-02382-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 04/02/2020] [Indexed: 05/23/2023]
Abstract
BACKGROUND To maintain sweetpotato (Ipomoea batatas (L.) Lam) growth and yield, sucrose must be transported from the leaves to the roots. Sucrose transporters or carriers (SUTs or SUCs) transport sucrose and are involved in plant growth and response to abiotic stress. However, the mechanisms of SUTs in sweetpotato abiotic stress resistance remains to be determined. RESULTS In the present study, we cloned a novel IbSUT4 gene; the protein encoded by this gene is localized in the tonoplast and plasma membrane. The plant growth was promoted in the IbSUT4 transgenic Arabidopsis thaliana lines, with increased expression of AtFT, a regulator of flowering time in plants. Over-expression of IbSUT4 in Arabidopsis thaliana resulted in higher sucrose content in the roots and lower sucrose content in the leaves, as compared to the wild-type (WT) plants, leading to improved stress tolerance during seedling growth. Moreover, we systematically analyzed the mechanisms of IbSUT4 in response to abiotic stress. The results suggest that the ABRE-motif was localized in the IbSUT4 promoter region, and the expression of the ABA signaling pathway genes (i.e., ABF2, ABF4, SnRK2.2, SnRK2.3, and PYL8/RCAR3) were induced, and the expression of ABI1 was inhibited. CONCLUSIONS Our dates provide evidence that IbSUT4 is not only involved in plant growth but also is an important positive regulator in plant stress tolerance through the ABF-dependent ABA signaling pathway.
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Affiliation(s)
- Dandan Wang
- State Key Laboratory of Crop Biology, College of Agronomic Science, Shandong Agricultural University, Tai' an, 271018, China
| | - Hongjuan Liu
- State Key Laboratory of Crop Biology, College of Agronomic Science, Shandong Agricultural University, Tai' an, 271018, China
| | - Hongxia Wang
- National Key of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of sciences, Shanghai, 200032, China
| | - Peng Zhang
- National Key of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of sciences, Shanghai, 200032, China
| | - Chunyu Shi
- State Key Laboratory of Crop Biology, College of Agronomic Science, Shandong Agricultural University, Tai' an, 271018, China.
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11
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Amlabu E, Ilani P, Opoku G, Nyarko PB, Quansah E, Thiam LG, Anim M, Ayivor-Djanie R, Akuh OA, Mensah-Brown H, Rayner JC, Awandare GA. Molecular Characterization and Immuno-Reactivity Patterns of a Novel Plasmodium falciparum Armadillo-Type Repeat Protein, PfATRP. Front Cell Infect Microbiol 2020; 10:114. [PMID: 32266165 PMCID: PMC7100384 DOI: 10.3389/fcimb.2020.00114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/02/2020] [Indexed: 01/30/2023] Open
Abstract
Nearly half of the genes in the Plasmodium falciparum genome have not yet been functionally investigated. We used homology-based structural modeling to identify multiple copies of Armadillo repeats within one uncharacterized gene expressed during the intraerythrocytic stages, PF3D7_0410600, subsequently referred to as P. falciparum Armadillo-Type Repeat Protein (PfATRP). Soluble recombinant PfATRP was expressed in a bacterial expression system, purified to apparent homogeneity and the identity of the recombinant PfATRP was confirmed by mass spectrometry. Affinity-purified α-PfATRP rabbit antibodies specifically recognized the recombinant protein. Immunofluorescence assays revealed that α-PfATRP rabbit antibodies reacted with P. falciparum schizonts. Anti-PfATRP antibody exhibited peripheral staining patterns around the merozoites. Given the localization of PfATRP in merozoites, we tested for an egress phenotype during schizont arrest assays and demonstrated that native PfATRP is inaccessible on the surface of merozoites in intact schizonts. Dual immunofluorescence assays with markers for the inner membrane complex (IMC) and microtubules suggest partial colocalization in both asexual and sexual stage parasites. Using the soluble recombinant PfATRP in a screen of plasma samples revealed that malaria-infected children have naturally acquired PfATRP-specific antibodies.
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Affiliation(s)
- Emmanuel Amlabu
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biochemistry, Kogi State University, Anyigba, Nigeria
| | - Philip Ilani
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Grace Opoku
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Prince B. Nyarko
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Evelyn Quansah
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Laty G. Thiam
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Manfred Anim
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Reuben Ayivor-Djanie
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biomedical Sciences, SBBS, University of Health and Allied Sciences, Ho, Ghana
| | - Ojo-ajogu Akuh
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Henrietta Mensah-Brown
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Julian C. Rayner
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Gordon A. Awandare
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
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12
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So WM, Kim SY, Hyoung S, Shin JS. The novel protein CSAP accelerates leaf senescence and is negatively regulated by SAUL1 in the dark. PLANT CELL REPORTS 2020; 39:325-334. [PMID: 31773253 DOI: 10.1007/s00299-019-02493-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/18/2019] [Indexed: 05/25/2023]
Abstract
The chloroplast-localized protein CSAP is an ABA-responsive factor and positively regulates dark-induced senescence. This phenomenon is controlled by SAUL1 in Arabidopsis. We report here that CSAP (Chloroplast-localized Senescence-Associated Protein, AT5G39520) functions as a positive regulator of senescence and is controlled by SAUL1 (Senescence Associated E3 Ubiquitin Ligase 1) in Arabidopsis. CSAP transcript level was gradually increased when senescence was progressed. Under dark conditions, the csap mutant showed delayed leaf senescence and reduced chlorophyll breakdown, but overexpression of CSAP accelerated leaf senescence and expressions of chlorophyll catabolic genes were up-regulated compared to the wild-type (WT). NCED3 and AAO3, which are involved in ABA biosynthesis, also showed higher expression in the overexpression lines than the WT. It is known that the CSAP transcript is increased in the saul1 mutant that shows precocious senescence. In our experiments, we confirmed that CSAP interacts with SAUL1 by the yeast two-hybrid and pull-down assays. In addition, we found that SAUL1 decreases the stability of CSAP in the presence of ABA. Taken together, we suggest that CSAP accelerates leaf senescence in the dark and this process is controlled by SAUL1.
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Affiliation(s)
- Won Mi So
- Division of Life Sciences, Korea University, Seoul, 02841, Korea
| | - Soo Youn Kim
- Division of Life Sciences, Korea University, Seoul, 02841, Korea
- Cloning Department, Bionics, Seoul, 04778, Korea
| | - Sujin Hyoung
- Division of Life Sciences, Korea University, Seoul, 02841, Korea
| | - Jeong Sheop Shin
- Division of Life Sciences, Korea University, Seoul, 02841, Korea.
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13
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Wang J, Liu S, Liu H, Chen K, Zhang P. PnSAG1, an E3 ubiquitin ligase of the Antarctic moss Pohlia nutans, enhanced sensitivity to salt stress and ABA. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 141:343-352. [PMID: 31207495 DOI: 10.1016/j.plaphy.2019.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/03/2019] [Accepted: 06/03/2019] [Indexed: 06/09/2023]
Abstract
Plant U-box (PUB) E3 ubiquitin ligases play crucial roles in the plant response to abiotic stress and the phytohormone abscisic acid (ABA) signaling, but little is known about them in bryophytes. Here, a representative U-box armadillo repeat (PUB-ARM) ubiquitin E3 ligase from Antarctic moss Pohlia nutans (PnSAG1), was explored for its role in abiotic stress response in Arabidopsis thaliana and Physcomitrella patens. The expression of PnSAG1 was rapidly induced by exogenous abscisic acid (ABA), salt, cold and drought stresses. PnSAG1 was localized to the cytoplasm and showed E3 ubiquitin ligase activity by in vitro ubiquitination assay. The PnSAG1-overexpressing Arabidopsis enhanced the sensitivity with respect to ABA and salt stress during seed germination and early root growth. Similarly, heterogeneous overexpression of PnSAG1 in P. patens was more sensitive to the salinity and ABA in their gametophyte growth. The analysis by RT-qPCR revealed that the expression of salt stress/ABA-related genes were downregulated in PnSAG1-overexpressing plants after salt treatment. Taken together, our results indicated that PnSAG1 plays a negative role in plant response to ABA and salt stress.
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Affiliation(s)
- Jing Wang
- National Glycoengineering Research Center and School of Life Science, Shandong University, Qingdao, 266237, China; Key Laboratory of Pediatrics, Liaocheng People's Hospital, Liaocheng, Shandong, 252000, China
| | - Shenghao Liu
- Marine Ecology Research Center, The First Institute of Oceanography, State Oceanic Administration, Qingdao, 266061, China
| | - Hongwei Liu
- National Glycoengineering Research Center and School of Life Science, Shandong University, Qingdao, 266237, China
| | - Kaoshan Chen
- National Glycoengineering Research Center and School of Life Science, Shandong University, Qingdao, 266237, China
| | - Pengying Zhang
- National Glycoengineering Research Center and School of Life Science, Shandong University, Qingdao, 266237, China.
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14
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Tao K, Waletich JR, Wise H, Arredondo F, Tyler BM. Tethering of Multi-Vesicular Bodies and the Tonoplast to the Plasma Membrane in Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:636. [PMID: 31396242 PMCID: PMC6662526 DOI: 10.3389/fpls.2019.00636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/26/2019] [Indexed: 05/05/2023]
Abstract
UNLABELLED Tethering of the plasma membrane (PM) and many organelles to the endoplasmic reticulum (ER) for communication and lipid exchange has been widely reported. However, despite growing interest in multi-vesicular bodies (MVBs) as possible sources of exosomes, tethering of MVBs to the PM has not been reported. Here we show that MVBs and the vacuolar membrane (tonoplast) could be tethered to the PM (PM-MVB/TP tethering) by artificial protein fusions or bimolecular fluorescence complementation (BiFC) complexes that contain a peripheral membrane protein that binds the PM and also a protein that binds MVBs or the tonoplast. PM-binding proteins capable of participating in PM-MVB/TP tethering included StRem1.3, BIK1, PBS1, CPK21, and the PtdIns(4)-binding proteins FAPP1 and Osh2. MVB/TP-binding proteins capable of participating in tethering included ARA6, ARA7, RHA1, RABG3f, and the PtdIns(3)P-binding proteins Vam7p and Hrs-2xFYVE. BiFC complexes or protein fusions capable of producing PM-MVB/TP tethering were visualized as large well-defined patches of fluorescence on the PM that could displace PM proteins such as AtFlotillin1 and also could displace cytoplasmic proteins such as soluble GFP. Furthermore, we identified paralogous ubiquitin E3 ligase proteins, SAUL1 (AtPUB44), and AtPUB43 that could produce PM-MVB/TP tethering. SAUL1 and AtPUB43 could produce tethering in uninfected tissue when paired with MVB-binding proteins or when their E3 ligase domain was deleted. When Nicotiana benthamiana leaf tissue was infected with Phytophthora capsici, full length SAUL1 and AtPUB43 localized in membrane patches consistent with PM-MVB/TP tethering. Our findings define new tools for studying PM-MVB/TP tethering and its possible role in plant defense. SIGNIFICANCE STATEMENT Although not previously observed, the tethering of multi-vesicular bodies to the plasma membrane is of interest due to the potential role of this process in producing exosomes in plants. Here we describe tools for observing and manipulating the tethering of multi-vesicular bodies and the tonoplast to the plant plasma membrane, and describe two plant proteins that may naturally regulate this process during infection.
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Affiliation(s)
- Kai Tao
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, United States
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Justin R. Waletich
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Hua Wise
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Felipe Arredondo
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Brett M. Tyler
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, United States
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, United States
- *Correspondence: Brett M. Tyler
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15
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Rottmann T, Fritz C, Sauer N, Stadler R. Glucose Uptake via STP Transporters Inhibits in Vitro Pollen Tube Growth in a HEXOKINASE1-Dependent Manner in Arabidopsis thaliana. THE PLANT CELL 2018; 30:2057-2081. [PMID: 30120167 PMCID: PMC6181011 DOI: 10.1105/tpc.18.00356] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/10/2018] [Accepted: 08/13/2018] [Indexed: 05/07/2023]
Abstract
Pollen tube growth requires a high amount of metabolic energy and precise targeting toward the ovules. Sugars, especially glucose, can serve as nutrients and as signaling molecules. Unexpectedly, in vitro assays revealed an inhibitory effect of glucose on pollen tube elongation, contradicting the hypothesis that monosaccharide uptake is a source of nutrition for growing pollen tubes. Measurements with Förster resonance energy transfer-based nanosensors revealed that glucose is taken up into pollen tubes and that the intracellular concentration is in the low micromolar range. Pollen tubes of stp4-6-8-9-10-11 sextuple knockout plants generated by crossings and CRISPR/Cas9 showed only a weak response to glucose, indicating that glucose uptake into pollen tubes is mediated mainly by these six monosaccharide transporters of the SUGAR TRANSPORT PROTEIN (STP) family. Analyses of HEXOKINASE1 (HXK1) showed a strong expression of this gene in pollen. Together with the glucose insensitivity and altered semi-in vivo growth rate of pollen tubes from hxk1 knockout lines, this strongly suggests that glucose is an important signaling molecule for pollen tubes, is taken up by STPs, and detected by HXK1. Equimolar amounts of fructose abolish the inhibitory effect of glucose indicating that only an excess of glucose is interpreted as a signal. This provides a possible model for the discrimination of signaling and nutritional sugars.
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Affiliation(s)
- Theresa Rottmann
- Molecular Plant Physiology, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Carolin Fritz
- Molecular Plant Physiology, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Norbert Sauer
- Molecular Plant Physiology, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Ruth Stadler
- Molecular Plant Physiology, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany
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16
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Chen G, Li X, Qiao X, Li J, Wang L, Kou X, Wu X, Wang G, Yin H, Wang P, Zhang S, Wu J. Genome-wide survey and expression analysis of the SLAC/SLAH gene family in pear (Pyrus bretschneideri) and other members of the Rosaceae. Genomics 2018; 111:1097-1107. [PMID: 31533901 DOI: 10.1016/j.ygeno.2018.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/11/2018] [Accepted: 07/05/2018] [Indexed: 01/08/2023]
Abstract
S-type anion channels, which play important roles in plant anion (such as nitrate and chloride) transport, growth and development, abiotic stress responses and hormone signaling. However, there is far less information about this family in Rosaceae species. We performed a genome-wide analysis and identified SLAC/SLAH gene family members in pear (Pyrus bretschneideri) and four other species of Rosaceae. A total of 21 SLAC/SLAH genes were identified from the five Rosaceae species. Based on the structural characteristics and a phylogenetic analysis of these genes, the SLAC/SLAH gene family could be classified into three main groups. Transcriptome data demonstrated that PbrSLAC/SLAH genes were detected in all parts of the pear. PbrSLAC/SLAH genes were only located on the plasma membrane in transient expression experiments in Arabidopsis protoplasts cells. These results provide valuable information that increases our understanding of the evolution, expression and functions of the SLAC/SLAH gene family in higher plants.
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Affiliation(s)
- Guodong Chen
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaolong Li
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Xin Qiao
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Jiaming Li
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Li Wang
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaobing Kou
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiao Wu
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Guoming Wang
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Hao Yin
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Peng Wang
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Shaoling Zhang
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Juyou Wu
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
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17
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Müdsam C, Wollschläger P, Sauer N, Schneider S. Sorting of Arabidopsis NRAMP3 and NRAMP4 depends on adaptor protein complex AP4 and a dileucine-based motif. Traffic 2018; 19:503-521. [PMID: 29573093 DOI: 10.1111/tra.12567] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 03/14/2018] [Accepted: 03/16/2018] [Indexed: 01/01/2023]
Abstract
Adaptor protein complexes mediate cargo selection and vesicle trafficking to different cellular membranes in all eukaryotic cells. Information on the role of AP4 in plants is still limited. Here, we present the analyses of Arabidopsis thaliana mutants lacking different subunits of AP4. These mutants show abnormalities in their development and in protein sorting. We found that growth of roots and etiolated hypocotyls, as well as male fertility and trichome morphology are disturbed in ap4. Analyses of GFP-fusions transiently expressed in mesophyll protoplasts demonstrated that the tonoplast (TP) proteins MOT2, NRAMP3 and NRAMP4, but not INT1, are partially sorted to the plasma membrane (PM) in the absence of a functional AP4 complex. Moreover, alanine mutagenesis revealed that in wild-type plants, sorting of NRAMP3 and NRAMP4 to the TP requires an N-terminal dileucine-based motif. The NRAMP3 or NRAMP4 N-terminal domain containing the dileucine motif was sufficient to redirect the PM localized INT4 protein to the TP and to confer AP4-dependency on sorting of INT1. Our data show that correct sorting of NRAMP3 and NRAMP4 depends on both, an N-terminal dileucine-based motif as well as AP4.
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Affiliation(s)
- Christina Müdsam
- Molecular Plant Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Paul Wollschläger
- Molecular Plant Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Norbert Sauer
- Molecular Plant Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Sabine Schneider
- Molecular Plant Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
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18
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Rottmann T, Klebl F, Schneider S, Kischka D, Rüscher D, Sauer N, Stadler R. Sugar Transporter STP7 Specificity for l-Arabinose and d-Xylose Contrasts with the Typical Hexose Transporters STP8 and STP12. PLANT PHYSIOLOGY 2018; 176:2330-2350. [PMID: 29311272 PMCID: PMC5841717 DOI: 10.1104/pp.17.01493] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 12/29/2017] [Indexed: 05/08/2023]
Abstract
The controlled distribution of sugars between assimilate-exporting source tissues and sugar-consuming sink tissues is a key element for plant growth and development. Monosaccharide transporters of the SUGAR TRANSPORT PROTEIN (STP) family contribute to the uptake of sugars into sink cells. Here, we report on the characterization of STP7, STP8, and STP12, three previously uncharacterized members of this family in Arabidopsis (Arabidopsis thaliana). Heterologous expression in yeast (Saccharomyces cerevisiae) revealed that STP8 and STP12 catalyze the high-affinity proton-dependent uptake of glucose and also accept galactose and mannose. STP12 additionally transports xylose. STP8 and STP12 are highly expressed in reproductive organs, where their protein products might contribute to sugar uptake into the pollen tube and the embryo sac. stp8.1 and stp12.1 T-DNA insertion lines developed normally, which may point toward functional redundancy with other STPs. In contrast to all other STPs, STP7 does not transport hexoses but is specific for the pentoses l-arabinose and d-xylose. STP7-promoter-reporter gene plants showed an expression of STP7 especially in tissues with high cell wall turnover, indicating that STP7 might contribute to the uptake and recycling of cell wall sugars. Uptake analyses with radioactive l-arabinose revealed that 11 other STPs are able to transport l-arabinose with high affinity. Hence, functional redundancy might explain the missing-mutant phenotype of two stp7 T-DNA insertion lines. Together, these data complete the characterization of the STP family and present the STPs as new l-arabinose transporters for potential biotechnological applications.
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Affiliation(s)
- Theresa Rottmann
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Franz Klebl
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Sabine Schneider
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Dominik Kischka
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - David Rüscher
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Norbert Sauer
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Ruth Stadler
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
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19
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Trujillo M. News from the PUB: plant U-box type E3 ubiquitin ligases. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:371-384. [PMID: 29237060 DOI: 10.1093/jxb/erx411] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/25/2017] [Indexed: 05/05/2023]
Abstract
Plant U-box type E3 ubiquitin ligases (PUBs) are well known for their functions in a variety of stress responses, including immune responses and the adaptation to abiotic stresses. First linked to pollen self-incompatibility, their repertoire of roles has grown to encompass also the regulation of developmental processes. Notably, new studies provide clues to their mode of action, underline the existence of conserved PUB-kinase modules, and suggest new links to G-protein signalling, placing PUBs at the crossroads of major signalling hubs. The frequent association with membranes, by interacting and/or targeting membrane proteins, as well as through a recently reported direct interaction with phospholipids, indicates a general function in the control of vesicle transport and their cargoes. This review aims to give an overview of the most significant advances in the field, while also trying to identify common themes of PUB function.
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Affiliation(s)
- Marco Trujillo
- Independent Junior Research Group-Ubiquitination in Immunity, Leibniz Institute of Plant Biochemistry, Germany
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20
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Rottmann TM, Fritz C, Lauter A, Schneider S, Fischer C, Danzberger N, Dietrich P, Sauer N, Stadler R. Protoplast-Esculin Assay as a New Method to Assay Plant Sucrose Transporters: Characterization of AtSUC6 and AtSUC7 Sucrose Uptake Activity in Arabidopsis Col-0 Ecotype. FRONTIERS IN PLANT SCIENCE 2018; 9:430. [PMID: 29740457 PMCID: PMC5925572 DOI: 10.3389/fpls.2018.00430] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/20/2018] [Indexed: 05/20/2023]
Abstract
The best characterized function of sucrose transporters of the SUC family in plants is the uptake of sucrose into the phloem for long-distance transport of photoassimilates. This important step is usually performed by one specific SUC in every species. However, plants possess small families of several different SUCs which are less well understood. Here, we report on the characterization of AtSUC6 and AtSUC7, two members of the SUC family in Arabidopsis thaliana. Heterologous expression in yeast (Saccharomyces cerevisiae) revealed that AtSUC6Col-0 is a high-affinity H+-symporter that mediates the uptake of sucrose and maltose across the plasma membrane at exceptionally low pH values. Reporter gene analyses revealed a strong expression of AtSUC6Col-0 in reproductive tissues, where the protein product might contribute to sugar uptake into pollen tubes and synergid cells. A knockout of AtSUC6 did not interfere with vegetative development or reproduction, which points toward physiological redundancy of AtSUC6Col-0 with other sugar transporters. Reporter gene analyses showed that AtSUC7Col-0 is expressed in roots and pollen tubes and that this sink specific expression of AtSUC7Col-0 is regulated by intragenic regions. Transport activity of AtSUC7Col-0 could not be analyzed in baker's yeast or Xenopus oocytes because the protein was not correctly targeted to the plasma membrane in both heterologous expression systems. Therefore, a novel approach to analyze sucrose transporters in planta was developed. Plasma membrane localized SUCs including AtSUC6Col-0 and also sucrose specific SWEETs were able to mediate transport of the fluorescent sucrose analog esculin in transformed mesophyll protoplasts. In contrast, AtSUC7Col-0 is not able to mediate esculin transport across the plasma membrane which implicates that AtSUC7Col-0 might be a non-functional pseudogene. The novel protoplast assay provides a useful tool for the quick and quantitative analysis of sucrose transporters in an in planta expression system.
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21
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Tong M, Kotur T, Liang W, Vogelmann K, Kleine T, Leister D, Brieske C, Yang S, Lüdke D, Wiermer M, Zhang Y, Li X, Hoth S. E3 ligase SAUL1 serves as a positive regulator of PAMP-triggered immunity and its homeostasis is monitored by immune receptor SOC3. THE NEW PHYTOLOGIST 2017; 215:1516-1532. [PMID: 28691210 DOI: 10.1111/nph.14678] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/26/2017] [Indexed: 05/08/2023]
Abstract
In both plants and animals, intracellular nucleotide-binding leucine-rich repeat proteins (NLRs; or Nod-like receptors) serve as immune receptors to recognize pathogen-derived molecules and mount effective immune responses against microbial infections. Plant NLRs often guard the presence or activity of other host proteins, which are the direct virulence targets of pathogen effectors. These guardees are sometimes immune-promoting components such as those in a mitogen-activated protein kinase cascade. Plant E3 ligases serve many roles in immune regulation, but it is unclear whether they can also be guarded by NLRs. Here, we report on an immune-regulating E3 ligase SAUL1, whose homeostasis is monitored by a Toll interleukin 1 receptor (TIR)-type NLR (TNL), SOC3. SOC3 can associate with SAUL1, and either loss or overexpression of SAUL1 triggers autoimmunity mediated by SOC3. By contrast, SAUL1 functions redundantly with its close homolog PUB43 to promote PAMP-triggered immunity (PTI). Taken together, the E3 ligase SAUL1 serves as a positive regulator of PTI and its homeostasis is monitored by the TNL SOC3.
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Affiliation(s)
- Meixuezi Tong
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Tanja Kotur
- Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, 22609, Hamburg, Germany
| | - Wanwan Liang
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Katja Vogelmann
- Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, 22609, Hamburg, Germany
| | - Tatjana Kleine
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München, 82152, Planegg-Martinsried, Germany
| | - Dario Leister
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München, 82152, Planegg-Martinsried, Germany
| | - Catharina Brieske
- Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, 22609, Hamburg, Germany
| | - Shuhua Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Daniel Lüdke
- RG Molecular Biology of Plant-Microbe Interactions, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Julia-Lermontowa-Weg 3, 37077, Goettingen, Germany
| | - Marcel Wiermer
- RG Molecular Biology of Plant-Microbe Interactions, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Julia-Lermontowa-Weg 3, 37077, Goettingen, Germany
| | - Yuelin Zhang
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Xin Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Stefan Hoth
- Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, 22609, Hamburg, Germany
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22
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Nieberl P, Ehrl C, Pommerrenig B, Graus D, Marten I, Jung B, Ludewig F, Koch W, Harms K, Flügge UI, Neuhaus HE, Hedrich R, Sauer N. Functional characterisation and cell specificity of BvSUT1, the transporter that loads sucrose into the phloem of sugar beet (Beta vulgaris L.) source leaves. PLANT BIOLOGY (STUTTGART, GERMANY) 2017; 19:315-326. [PMID: 28075052 DOI: 10.1111/plb.12546] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 01/07/2017] [Indexed: 05/08/2023]
Abstract
Sugar beet (Beta vulgaris L.) is one of the most important sugar-producing plants worldwide and provides about one third of the sugar consumed by humans. Here we report on molecular characterisation of the BvSUT1 gene and on the functional characterisation of the encoded transporter. In contrast to the recently identified tonoplast-localised sucrose transporter BvTST2.1 from sugar beet taproots, which evolved within the monosaccharide transporter (MST) superfamily, BvSUT1 represents a classical sucrose transporter and is a typical member of the disaccharide transporter (DST) superfamily. Transgenic Arabidopsis plants expressing the β-GLUCURONIDASE (GUS) reporter gene under control of the BvSUT1-promoter showed GUS histochemical staining of their phloem; an anti-BvSUT1-antiserum identified the BvSUT1 transporter specifically in phloem companion cells. After expression of BvSUT1 cDNA in bakers' yeasts (Saccharomyces cerevisiae) uptake characteristics of the BvSUT1 protein were studied. Moreover, the sugar beet transporter was characterised as a proton-coupled sucrose symporter in Xenopus laevis oocytes. Our findings indicate that BvSUT1 is the sucrose transporter that is responsible for loading of sucrose into the phloem of sugar beet source leaves delivering sucrose to the storage tissue in sugar beet taproot sinks.
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Affiliation(s)
- P Nieberl
- Molecular Plant Physiology (MPP), FAU Erlangen-Nürnberg, Erlangen, Germany
| | - C Ehrl
- Molecular Plant Physiology (MPP), FAU Erlangen-Nürnberg, Erlangen, Germany
| | - B Pommerrenig
- Molecular Plant Physiology (MPP), FAU Erlangen-Nürnberg, Erlangen, Germany
| | - D Graus
- Biophysics and Molecular Plant Physiology, University of Würzburg, Würzburg, Germany
| | - I Marten
- Biophysics and Molecular Plant Physiology, University of Würzburg, Würzburg, Germany
| | - B Jung
- Plant Physiology, University of Kaiserslautern, Kaiserslautern, Germany
| | - F Ludewig
- Biocenter Cologne, Botanical Institute II and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - W Koch
- KWS Saat AG, Einbeck, Germany
| | - K Harms
- SÜDZUCKER AG, CRDS, Obrigheim/Pfalz, Germany
| | - U-I Flügge
- Biocenter Cologne, Botanical Institute II and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - H E Neuhaus
- Plant Physiology, University of Kaiserslautern, Kaiserslautern, Germany
| | - R Hedrich
- Biophysics and Molecular Plant Physiology, University of Würzburg, Würzburg, Germany
| | - N Sauer
- Molecular Plant Physiology (MPP), FAU Erlangen-Nürnberg, Erlangen, Germany
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23
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Tunc-Ozdemir M, Jones AM. Ligand-induced dynamics of heterotrimeric G protein-coupled receptor-like kinase complexes. PLoS One 2017; 12:e0171854. [PMID: 28187200 PMCID: PMC5302818 DOI: 10.1371/journal.pone.0171854] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/26/2017] [Indexed: 02/08/2023] Open
Abstract
Background Arabidopsis, 7-transmembrane Regulator of G signaling protein 1 (AtRGS1) modulates canonical G protein signaling by promoting the inactive state of heterotrimeric G protein complex on the plasma membrane. It is known that plant leucine-rich repeat receptor–like kinases (LRR RLKs) phosphorylate AtRGS1 in vitro but little is known about the in vivo interaction, molecular dynamics, or the cellular consequences of this interaction. Methods Therefore, a subset of the known RLKs that phosphorylate AtRGS1 were selected for elucidation, namely, BAK1, BIR1, FLS2. Several microscopies for both static and dynamic protein-protein interactions were used to follow in vivo interactions between the RLKs and AtRGS1 after the presentation of the Pathogen-associated Molecular Pattern, Flagellin 22 (Flg22). These microscopies included Förster Resonance Energy Transfer, Bimolecular Fluoresence Complementation, and Cross Number and Brightness Fluorescence Correlation Spectroscopy. In addition, reactive oxygen species and calcium changes in living cells were quantitated using luminometry and R-GECO1 microscopy. Results The LRR RLKs BAK1 and BIR1, interact with AtRGS1 at the plasma membrane. The RLK ligand flg22 sets BAK1 in motion toward AtRGS1 and BIR1 away, both returning to the baseline orientations by 10 minutes. The C-terminal tail of AtRGS1 is important for the interaction with BAK1 and for the tempo of the AtRGS1/BIR1 dynamics. This window of time corresponds to the flg22-induced transient production of reactive oxygen species and calcium release which are both attenuated in the rgs1 and the bak1 null mutants. Conclusions A temporal model of these interactions is proposed. flg22 binding induces nearly instantaneous dimerization between FLS2 and BAK1. Phosphorylated BAK1 interacts with and enables AtRGS1 to move away from BIR1 and AtRGS1 becomes phosphorylated leading to its endocytosis thus leading to de-repression by permitting AtGPA1 to exchange GDP for GTP. Finally, the G protein complex becomes dissociated thus AGB1 interacts with its effector proteins leading to changes in reactive oxygen species and calcium.
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Affiliation(s)
- Meral Tunc-Ozdemir
- Department of Biology University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Alan M. Jones
- Department of Biology University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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24
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Seo DH, Ahn MY, Park KY, Kim EY, Kim WT. The N-Terminal UND Motif of the Arabidopsis U-Box E3 Ligase PUB18 Is Critical for the Negative Regulation of ABA-Mediated Stomatal Movement and Determines Its Ubiquitination Specificity for Exocyst Subunit Exo70B1. THE PLANT CELL 2016; 28:2952-2973. [PMID: 27956469 PMCID: PMC5240735 DOI: 10.1105/tpc.16.00347] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 11/18/2016] [Accepted: 12/09/2016] [Indexed: 05/20/2023]
Abstract
The Arabidopsis thaliana U-box E3 ligases PUB18/PUB19 and PUB22/PUB23 are negative regulators of drought stress responses. PUB18/PUB19 regulate the drought stress response in an abscisic acid (ABA)-dependent manner, whereas PUB22/PUB23 regulate this response in an ABA-independent manner. A major structural difference between PUB18/PUB19 and PUB22/PUB23 is the presence of the UND (U-box N-terminal domain). Here, we focused on elucidating the molecular mechanism that mediates the functional difference between PUB18 and PUB22 and found that the UNDPUB18 was critically involved in the negative regulation of ABA-mediated stomatal movements. Exo70B1, a subunit of the exocyst complex, was identified as a target of PUB18, whereas Exo70B2 was a substrate of PUB22. However, the ∆UND-PUB18 derivative failed to ubiquitinate Exo70B1, but ubiquitinated Exo70B2. By contrast, the UNDPUB18-PUB22 chimeric protein ubiquitinated Exo70B1 instead of Exo70B2, suggesting that the ubiquitination specificities of PUB18 and PUB22 to Exo70B1 and Exo70B2, respectively, are dependent on the presence or absence of the UNDPUB18 motif. The ABA-insensitive phenotypes of the pub18 pub19 exo70b1 triple mutant were reminiscent of those of exo70b1 rather than pub18 pub19, indicating that Exo70B1 functions downstream of PUB18. Overall, our results suggest that the UNDPUB18 motif is crucial for the negative regulation of ABA-dependent stomatal movement and for determination of its ubiquitination specificity to Exo70B1.
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Affiliation(s)
- Dong Hye Seo
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Min Yong Ahn
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Ki Youl Park
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Eun Yu Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Woo Taek Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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25
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Lee IH, Lee IC, Kim J, Kim JH, Chung EH, Kim HJ, Park SJ, Kim YM, Kang SK, Nam HG, Woo HR, Lim PO. NORE1/SAUL1 integrates temperature-dependent defense programs involving SGT1b and PAD4 pathways and leaf senescence in Arabidopsis. PHYSIOLOGIA PLANTARUM 2016; 158:180-99. [PMID: 26910207 DOI: 10.1111/ppl.12434] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/16/2015] [Accepted: 01/06/2016] [Indexed: 05/06/2023]
Abstract
Leaf senescence is not only primarily governed by developmental age but also influenced by various internal and external factors. Although some genes that control leaf senescence have been identified, the detailed regulatory mechanisms underlying integration of diverse senescence-associated signals into the senescence programs remain to be elucidated. To dissect the regulatory pathways involved in leaf senescence, we isolated the not oresara1-1 (nore1-1) mutant showing accelerated leaf senescence phenotypes from an EMS-mutagenized Arabidopsis thaliana population. We found that altered transcriptional programs in defense response-related processes were associated with the accelerated leaf senescence phenotypes observed in nore1-1 through microarray analysis. The nore1-1 mutation activated defense program, leading to enhanced disease resistance. Intriguingly, high ambient temperature effectively suppresses the early senescence and death phenotypes of nore1-1. The gene responsible for the phenotypes of nore1-1 contains a missense mutation in SENESCENCE-ASSOCIATED E3 UBIQUITIN LIGASE 1 (SAUL1), which was reported as a negative regulator of premature senescence in the light intensity- and PHYTOALEXIN DEFICIENT 4 (PAD4)-dependent manner. Through extensive double mutant analyses, we recently identified suppressor of the G2 Allele of SKP1b (SGT1b), one of the positive regulators for disease resistance conferred by many resistance (R) proteins, as a downstream signaling component in NORE1-mediated senescence and cell death pathways. In conclusion, NORE1/SAUL1 is a key factor integrating signals from temperature-dependent defense programs and leaf senescence in Arabidopsis. These findings provide a new insight that plants might utilize defense response program in regulating leaf senescence process, possibly through recruiting the related genes during the evolution of the leaf senescence program.
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Affiliation(s)
- Il Hwan Lee
- Department of Life Sciences, POSTECH, Pohang, 37673, Republic of Korea
| | - In Chul Lee
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea
| | - Jeongsik Kim
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea
| | - Jin Hee Kim
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea
| | - Eui-Hwan Chung
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Hyo Jung Kim
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea
| | - Su Jin Park
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang, 37673, Republic of Korea
| | - Yong Min Kim
- Department of Bioscience, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Sin Kyu Kang
- Department of Bioscience, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Hong Gil Nam
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea.
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea.
| | - Hye Ryun Woo
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea.
| | - Pyung Ok Lim
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea.
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26
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Pertl-Obermeyer H, Wu XN, Schrodt J, Müdsam C, Obermeyer G, Schulze WX. Identification of Cargo for Adaptor Protein (AP) Complexes 3 and 4 by Sucrose Gradient Profiling. Mol Cell Proteomics 2016; 15:2877-89. [PMID: 27371946 DOI: 10.1074/mcp.m116.060129] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Indexed: 11/06/2022] Open
Abstract
Intracellular vesicle trafficking is a fundamental process in eukaryotic cells. It enables cellular polarity and exchange of proteins between subcellular compartments such as the plasma membrane or the vacuole. Adaptor protein complexes participate in the vesicle formation by specific selection of the transported cargo. We investigated the role of the adaptor protein complex 3 (AP-3) and adaptor protein complex 4 (AP-4) in this selection process by screening for AP-3 and AP-4 dependent cargo proteins. Specific cargo proteins are expected to be mis-targeted in knock-out mutants of adaptor protein complex components. Thus, we screened for altered distribution profiles across a density gradient of membrane proteins in wild type versus ap-3β and ap-4β knock-out mutants. In ap-3β mutants, especially proteins with transport functions, such as aquaporins and plasma membrane ATPase, as well as vesicle trafficking proteins showed differential protein distribution profiles across the density gradient. In the ap-4β mutant aquaporins but also proteins from lipid metabolism were differentially distributed. These proteins also showed differential phosphorylation patterns in ap-3β and ap-4β compared with wild type. Other proteins, such as receptor kinases were depleted from the AP-3 mutant membrane system, possibly because of degradation after mis-targeting. In AP-4 mutants, membrane fractions were depleted for cytochrome P450 proteins, cell wall proteins and receptor kinases. Analysis of water transport capacity in wild type and mutant mesophyll cells confirmed aquaporins as cargo proteins of AP-3 and AP-4. The combination of organelle density gradients with proteome analysis turned out as a suitable experimental strategy for large-scale analyses of protein trafficking.
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Affiliation(s)
- Heidi Pertl-Obermeyer
- From the ‡Department of Plant Systems Biology, University of Hohenheim, 70593 Stuttgart, Germany
| | - Xu Na Wu
- From the ‡Department of Plant Systems Biology, University of Hohenheim, 70593 Stuttgart, Germany
| | - Jens Schrodt
- From the ‡Department of Plant Systems Biology, University of Hohenheim, 70593 Stuttgart, Germany
| | - Christina Müdsam
- ¶Molecular Plant Physiology, University of Erlangen, Staudtstraβe 5, 91058 Erlangen, Germany
| | - Gerhard Obermeyer
- §Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of Salzburg, Billrothstraβe 11, 5020 Salzburg, Austria
| | - Waltraud X Schulze
- From the ‡Department of Plant Systems Biology, University of Hohenheim, 70593 Stuttgart, Germany;
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27
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Wang N, Liu Y, Cong Y, Wang T, Zhong X, Yang S, Li Y, Gai J. Genome-Wide Identification of Soybean U-Box E3 Ubiquitin Ligases and Roles of GmPUB8 in Negative Regulation of Drought Stress Response in Arabidopsis. PLANT & CELL PHYSIOLOGY 2016; 57:1189-209. [PMID: 27057003 DOI: 10.1093/pcp/pcw068] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 03/13/2016] [Indexed: 05/05/2023]
Abstract
Plant U-box (PUB) E3 ubiquitin ligases play important roles in hormone signaling pathways and response to abiotic stresses, but little is known about them in soybean, Glycine max. Here, we identified and characterized 125 PUB genes from the soybean genome, which were classified into eight groups according to their protein domains. Soybean PUB genes (GmPUB genes) are broadly expressed in many tissues and are a little more abundant in the roots than in the other tissues. Nine GmPUB genes, GmPUB1-GmPUB9, showed induced expression patterns by drought, and the expression of GmPUB8 was also induced by exogenous ABA and NaCl. GmPUB8 was localized to post-Golgi compartments, interacting with GmE2 protein as demonstrated by yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) experiments, and showed E3 ubiquitin ligase activity by in vitro ubiquitination assay. Heterogeneous overexpression of GmPUB8 in Arabidopsis showed decreased drought tolerance, enhanced sensitivity with respect to osmotic and salt stress inhibition of seed germination and seedling growth, and inhibited ABA- and mannitol-mediated stomatal closure. Eight drought stress-related genes were less induced in GmPUB8-overexpressing Arabidopsis after drought treatment compared with the wild type and the pub23 mutant. Taken together, our results suggested that GmPUB8 might negatively regulate plant response to drought stress. In addition, Y2H and BiFC showed that GmPUB8 interacted with soybean COL (CONSTANS LIKE) protein. GmPUB8-overexpressing Arabidopsis flowered earlier under middle- and short-day conditions but later under long-day conditions, indicating that GmPUB8 might regulate flowering time in the photoperiod pathway. This study helps us to understand the functions of PUB E3 ubiquitin ligases in soybean.
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Affiliation(s)
- Ning Wang
- National Key Laboratory of Crop Genetics and Germplasm Enhancement/National Center for Soybean Improvement/Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture)/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing 210095, China
| | - Yaping Liu
- National Key Laboratory of Crop Genetics and Germplasm Enhancement/National Center for Soybean Improvement/Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture)/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing 210095, China
| | - Yahui Cong
- National Key Laboratory of Crop Genetics and Germplasm Enhancement/National Center for Soybean Improvement/Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture)/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing 210095, China
| | - Tingting Wang
- National Key Laboratory of Crop Genetics and Germplasm Enhancement/National Center for Soybean Improvement/Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture)/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiujuan Zhong
- National Key Laboratory of Crop Genetics and Germplasm Enhancement/National Center for Soybean Improvement/Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture)/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing 210095, China
| | - Shouping Yang
- National Key Laboratory of Crop Genetics and Germplasm Enhancement/National Center for Soybean Improvement/Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture)/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing 210095, China
| | - Yan Li
- National Key Laboratory of Crop Genetics and Germplasm Enhancement/National Center for Soybean Improvement/Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture)/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing 210095, China
| | - Junyi Gai
- National Key Laboratory of Crop Genetics and Germplasm Enhancement/National Center for Soybean Improvement/Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture)/Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing 210095, China
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28
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Rottmann T, Zierer W, Subert C, Sauer N, Stadler R. STP10 encodes a high-affinity monosaccharide transporter and is induced under low-glucose conditions in pollen tubes of Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2387-99. [PMID: 26893494 PMCID: PMC4809294 DOI: 10.1093/jxb/erw048] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Pollen tubes are fast growing, photosynthetically inactive cells. Their energy demand is covered by specific transport proteins in the plasma membrane that mediate the uptake of sugars. Here we report on the functional characterization of AtSTP10, a previously uncharacterized member of the SUGAR TRANSPORT PROTEIN family. Heterologous expression of STP10 cDNA in yeast revealed that the encoded protein catalyses the high-affinity uptake of glucose, galactose and mannose. The transporter is sensitive to uncouplers of transmembrane proton gradients, indicating that the protein acts as a hexose-H(+)symporter. Analyses of STP10 mRNA and STP10 promoter-reporter gene studies revealed a sink-specific expression pattern of STP10 in primordia of lateral roots and in pollen tubes. This restriction to sink organs is mediated by intragenic regions of STP10 qPCR analyses with cDNA of in vitro grown pollen tubes showed that STP10 expression was down-regulated in the presence of 50mM glucose. However, in pollen tubes of glucose-insensitive plants, which lack the glucose sensor hexokinase1 (HXK1), no glucose-induced down-regulation of STP10 expression was detected. A stp10T-DNA insertion line developed normally, which may point towards functional redundancy. The data presented in this paper indicate that a high-affinity glucose uptake system is induced in growing pollen tubes under low glucose conditions and that this regulation may occur through the hexokinase pathway.
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Affiliation(s)
- Theresa Rottmann
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Wolfgang Zierer
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Christa Subert
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Norbert Sauer
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Ruth Stadler
- Molecular Plant Physiology, University Erlangen-Nürnberg, 91058 Erlangen, Germany
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29
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Zierer W, Hajirezaei MR, Eggert K, Sauer N, von Wirén N, Pommerrenig B. Phloem-Specific Methionine Recycling Fuels Polyamine Biosynthesis in a Sulfur-Dependent Manner and Promotes Flower and Seed Development. PLANT PHYSIOLOGY 2016; 170:790-806. [PMID: 26662272 PMCID: PMC4734553 DOI: 10.1104/pp.15.00786] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 12/06/2015] [Indexed: 05/17/2023]
Abstract
The Yang or Met Cycle is a series of reactions catalyzing the recycling of the sulfur (S) compound 5'-methylthioadenosine (MTA) to Met. MTA is produced as a by-product in ethylene, nicotianamine, and polyamine biosynthesis. Whether the Met Cycle preferentially fuels one of these pathways in a S-dependent manner remained unclear so far. We analyzed Arabidopsis (Arabidopsis thaliana) mutants with defects in the Met Cycle enzymes 5-METHYLTHIORIBOSE-1-PHOSPHATE-ISOMERASE1 (MTI1) and DEHYDRATASE-ENOLASE-PHOSPHATASE-COMPLEX1 (DEP1) under different S conditions and assayed the contribution of the Met Cycle to the regeneration of S for these pathways. Neither mti1 nor dep1 mutants could recycle MTA but showed S-dependent reproductive failure, which was accompanied by reduced levels of the polyamines putrescine, spermidine, and spermine in mutant inflorescences. Complementation experiments with external application of these three polyamines showed that only the triamine spermine could specifically rescue the S-dependent reproductive defects of the mutant plants. Furthermore, expressing gene-reporter fusions in Arabidopsis showed that MTI1 and DEP1 were mainly expressed in the vasculature of all plant parts. Phloem-specific reconstitution of Met Cycle activity in mti1 and dep1 mutant plants was sufficient to rescue their S-dependent mutant phenotypes. We conclude from these analyses that phloem-specific S recycling during periods of S starvation is essential for the biosynthesis of polyamines required for flowering and seed development.
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Affiliation(s)
- Wolfgang Zierer
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Biology, Molecular Plant Physiology, 91058 Erlangen, Germany (W.Z., N.S.); andMolecular Plant Nutrition (M.R.H., K.E., N.v.W.) and Metalloid Transport (B.P.), Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), 06466 Gatersleben, Germany
| | - Mohammad R Hajirezaei
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Biology, Molecular Plant Physiology, 91058 Erlangen, Germany (W.Z., N.S.); andMolecular Plant Nutrition (M.R.H., K.E., N.v.W.) and Metalloid Transport (B.P.), Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), 06466 Gatersleben, Germany
| | - Kai Eggert
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Biology, Molecular Plant Physiology, 91058 Erlangen, Germany (W.Z., N.S.); andMolecular Plant Nutrition (M.R.H., K.E., N.v.W.) and Metalloid Transport (B.P.), Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), 06466 Gatersleben, Germany
| | - Norbert Sauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Biology, Molecular Plant Physiology, 91058 Erlangen, Germany (W.Z., N.S.); andMolecular Plant Nutrition (M.R.H., K.E., N.v.W.) and Metalloid Transport (B.P.), Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), 06466 Gatersleben, Germany
| | - Nicolaus von Wirén
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Biology, Molecular Plant Physiology, 91058 Erlangen, Germany (W.Z., N.S.); andMolecular Plant Nutrition (M.R.H., K.E., N.v.W.) and Metalloid Transport (B.P.), Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), 06466 Gatersleben, Germany
| | - Benjamin Pommerrenig
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Biology, Molecular Plant Physiology, 91058 Erlangen, Germany (W.Z., N.S.); andMolecular Plant Nutrition (M.R.H., K.E., N.v.W.) and Metalloid Transport (B.P.), Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), 06466 Gatersleben, Germany
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Disch EM, Tong M, Kotur T, Koch G, Wolf CA, Li X, Hoth S. Membrane-Associated Ubiquitin Ligase SAUL1 Suppresses Temperature- and Humidity-Dependent Autoimmunity in Arabidopsis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:69-80. [PMID: 26505534 DOI: 10.1094/mpmi-07-15-0146-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Plants have evolved elaborate mechanisms to regulate pathogen defense. Imbalances in this regulation may result in autoimmune responses that are affecting plant growth and development. In Arabidopsis, SAUL1 encodes a plant U-box ubiquitin ligase and regulates senescence and cell death. Here, we show that saul1-1 plants exhibit characteristics of an autoimmune mutant. A decrease in relative humidity or temperature resulted in reduced growth and systemic lesioning of saul1-1 rosettes. These physiological changes are associated with increased expression of salicylic acid-dependent and pathogenesis-related (PR) genes. Consistently, resistance of saul1-1 plants against Pseudomonas syringae pv. maculicola ES4326, P. syringae pv. tomato DC3000, or Hyaloperonospora arabidopsidis Noco2 was enhanced. Transmission electron microscopy revealed alterations in saul1-1 chloroplast ultrastructure and cell-wall depositions. Confocal analysis on aniline blue-stained leaf sections and cellular universal micro spectrophotometry further showed that these cell-wall depositions contain callose and lignin. To analyze signaling downstream of SAUL1, we performed epistasis analyses between saul1-1 and mutants in the EDS1/PAD4/SAG101 hub. All phenotypes observed in saul1-1 plants at low temperature were dependent on EDS1 and PAD4 but not SAG101. Taken together, SAUL1 negatively regulates immunity upstream of EDS1/PAD4, likely through the degradation of an unknown activator of the pathway.
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Affiliation(s)
- Eva-Maria Disch
- 1 Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, Hamburg, Germany
| | - Meixuezi Tong
- 2 Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Tanja Kotur
- 1 Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, Hamburg, Germany
| | - Gerald Koch
- 3 Thünen-Institute of Wood Technology and Wood Biology, Hamburg, Germany
| | - Carl-Asmus Wolf
- 1 Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, Hamburg, Germany
| | - Xin Li
- 2 Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Stefan Hoth
- 1 Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, Hamburg, Germany
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Tian YP, Valkonen JPT. Recombination of strain O segments to HCpro-encoding sequence of strain N of Potato virus Y modulates necrosis induced in tobacco and in potatoes carrying resistance genes Ny or Nc. MOLECULAR PLANT PATHOLOGY 2015; 16:735-47. [PMID: 25557768 PMCID: PMC6638495 DOI: 10.1111/mpp.12231] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Hypersensitive resistance (HR) to strains O and C of Potato virus Y (PVY, genus Potyvirus) is conferred by potato genes Ny(tbr) and Nc(tbr), respectively; however, PVY N strains overcome these resistance genes. The viral helper component proteinases (HCpro, 456 amino acids) from PVY(N) and PVY(O) are distinguished by an eight-amino-acid signature sequence, causing HCpro to fold into alternative conformations. Substitution of only two residues (K269R and R270K) of the eight-amino-acid signature in PVY(N) HCpro was needed to convert the three-dimensional (3D) model of PVY(N) HCpro to a PVY(O) -like conformation and render PVY(N) avirulent in the presence of Ny(tbr), whereas four amino acid substitutions were necessary to change PVY(O) HCpro to a PVY(N) -like conformation. Hence, the HCpro conformation rather than other features ascribed to the sequence were essential for recognition by Ny(tbr). The 3D model of PVY(C) HCpro closely resembled PVY(O), but differed from PVY(N) HCpro. HCpro of all strains was structurally similar to β-catenin. Sixteen PVY(N) 605-based chimeras were inoculated to potato cv. Pentland Crown (Ny(tbr)), King Edward (Nc(tbr)) and Pentland Ivory (Ny(tbr)/Nc(tbr)). Eleven chimeras induced necrotic local lesions and caused no systemic infection, and thus differed from both parental viruses that infected King Edward systemically, and from PVY(N) 605 that infected Pentland Crown and Pentland Ivory systemically. These 11 chimeras triggered both Ny(tbr) and Nc(tbr) and, in addition, six induced veinal necrosis in tobacco. Further, specific amino acid residues were found to have an additive impact on necrosis. These results shed new light on the causes of PVY-related necrotic symptoms in potato.
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Affiliation(s)
- Yan-Ping Tian
- Department of Agricultural Sciences, University of Helsinki, PO Box 27, FI-00014, Helsinki, Finland
| | - Jari P T Valkonen
- Department of Agricultural Sciences, University of Helsinki, PO Box 27, FI-00014, Helsinki, Finland
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Genome-wide survey and expression analysis of the PUB family in Chinese cabbage (Brassica rapa ssp. pekinesis). Mol Genet Genomics 2015; 290:2241-60. [DOI: 10.1007/s00438-015-1075-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 05/27/2015] [Indexed: 10/23/2022]
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Wolfenstetter S, Chakravorty D, Kula R, Urano D, Trusov Y, Sheahan MB, McCurdy DW, Assmann SM, Jones AM, Botella JR. Evidence for an unusual transmembrane configuration of AGG3, a class C Gγ subunit of Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:388-98. [PMID: 25430066 PMCID: PMC4334566 DOI: 10.1111/tpj.12732] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 11/19/2014] [Accepted: 11/21/2014] [Indexed: 05/20/2023]
Abstract
Heterotrimeric G proteins are crucial for the perception of external signals and subsequent signal transduction in animal and plant cells. In both model systems, the complex comprises one Gα, one Gβ, and one Gγ subunit. However, in addition to the canonical Gγ subunits (class A), plants also possess two unusual, plant-specific classes of Gγ subunits (classes B and C) that have not yet been found in animals. These include Gγ subunits lacking the C-terminal CaaX motif (class B), which is important for membrane anchoring of the protein; the presence of such subunits gives rise to a flexible sub-population of Gβ/γ heterodimers that are not necessarily restricted to the plasma membrane. Plants also contain class C Gγ subunits, which are twice the size of canonical Gγ subunits, with a predicted transmembrane domain and a large cysteine-rich extracellular C-terminus. However, neither the presence of the transmembrane domain nor the membrane topology have been unequivocally demonstrated. Here, we provide compelling evidence that AGG3, a class C Gγ subunit of Arabidopsis, contains a functional transmembrane domain, which is sufficient but not essential for plasma membrane localization, and that the cysteine-rich C-terminus is extracellular.
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Affiliation(s)
- Susanne Wolfenstetter
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, United States of America
| | - David Chakravorty
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane 4072, Australia
- Biology Department, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802, USA
| | - Ryan Kula
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, United States of America
| | - Daisuke Urano
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, United States of America
| | - Yuri Trusov
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane 4072, Australia
| | - Michael B. Sheahan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, 2308 Australia
| | - David W. McCurdy
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, 2308 Australia
| | - Sarah M. Assmann
- Biology Department, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802, USA
| | - Alan M. Jones
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, United States of America
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, United States of America
- To whom correspondence should be addressed.
| | - Jose R. Botella
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane 4072, Australia
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Callis J. The ubiquitination machinery of the ubiquitin system. THE ARABIDOPSIS BOOK 2014; 12:e0174. [PMID: 25320573 PMCID: PMC4196676 DOI: 10.1199/tab.0174] [Citation(s) in RCA: 216] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The protein ubiquitin is a covalent modifier of proteins, including itself. The ubiquitin system encompasses the enzymes required for catalysing attachment of ubiquitin to substrates as well as proteins that bind to ubiquitinated proteins leading them to their final fate. Also included are activities that remove ubiquitin independent of, or in concert with, proteolysis of the substrate, either by the proteasome or proteases in the vacuole. In addition to ubiquitin encoded by a family of fusion proteins, there are proteins with ubiquitin-like domains, likely forming ubiquitin's β-grasp fold, but incapable of covalent modification. However, they serve as protein-protein interaction platforms within the ubiquitin system. Multi-gene families encode all of these types of activities. Within the ubiquitination machinery "half" of the ubiquitin system are redundant, partially redundant, and unique components affecting diverse developmental and environmental responses in plants. Notably, multiple aspects of biotic and abiotic stress responses require, or are modulated by, ubiquitination. Finally, aspects of the ubiquitin system have broad utility: as components to enhance gene expression or to regulate protein abundance. This review focuses on the ubiquitination machinery: ubiquitin, unique aspects about the synthesis of ubiquitin and organization of its gene family, ubiquitin activating enzymes (E1), ubiquitin conjugating enzymes (E2) and ubiquitin ligases, or E3s. Given the large number of E3s in Arabidopsis this review covers the U box, HECT and RING type E3s, with the exception of the cullin-based E3s.
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Affiliation(s)
- Judy Callis
- Department of Molecular and Cellular Biology, University of California-Davis, Davis CA 95616
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Sharma M, Singh A, Shankar A, Pandey A, Baranwal V, Kapoor S, Tyagi AK, Pandey GK. Comprehensive expression analysis of rice Armadillo gene family during abiotic stress and development. DNA Res 2014; 21:267-83. [PMID: 24398598 PMCID: PMC4060948 DOI: 10.1093/dnares/dst056] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genes in the Armadillo (ARM)-repeat superfamily encode proteins with a range of developmental and physiological processes in unicellular and multicellular eukaryotes. These 42 amino acid, long tandem repeat-containing proteins have been abundantly recognized in many plant species. Previous studies have confirmed that Armadillo proteins constitute a multigene family in Arabidopsis. In this study, we performed a computational analysis in the rice genome (Oryza sativa L. subsp. japonica), and identified 158 genes of Armadillo superfamily. Phylogenetic study classified them into several arbitrary groups based on a varying number of non-conserved ARM repeats and accessory domain(s) associated with them. An in-depth analysis of gene expression through microarray and Q-PCR revealed a number of ARM proteins expressing differentially in abiotic stresses and developmental conditions, suggesting a potential roles of this superfamily in development and stress signalling. Comparative phylogenetic analysis between Arabidopsis and rice Armadillo genes revealed a high degree of evolutionary conservation between the orthologues in two plant species. The non-synonymous and synonymous substitutions per site ratios (Ka/Ks) of duplicated gene pairs indicate a purifying selection. This genome-wide identification and expression analysis provides a basis for further functional analysis of Armadillo genes under abiotic stress and reproductive developmental condition in the plant lineage.
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Affiliation(s)
- Manisha Sharma
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi 110021, India
| | - Amarjeet Singh
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi 110021, India
| | - Alka Shankar
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi 110021, India
| | - Amita Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi 110021, India
| | - Vinay Baranwal
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi 110021, India
| | - Sanjay Kapoor
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi 110021, India
| | - Akhilesh K Tyagi
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi 110021, India National Institute of Plant Genome Research, Aruna Asaf Ali Road, New Delhi 110067, India
| | - Girdhar K Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi 110021, India
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Vogelmann K, Subert C, Danzberger N, Drechsel G, Bergler J, Kotur T, Burmester T, Hoth S. Plasma membrane-association of SAUL1-type plant U-box armadillo repeat proteins is conserved in land plants. FRONTIERS IN PLANT SCIENCE 2014; 5:37. [PMID: 24600457 PMCID: PMC3928556 DOI: 10.3389/fpls.2014.00037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 01/27/2014] [Indexed: 05/08/2023]
Abstract
Post-translational protein modification plays a pivotal role in the regulation and specific turnover of proteins. One of these important modifications is the ubiquitination of target proteins, which can occur at distinct cellular compartments. At the plasma membrane, ubiquitination regulates the internalization and thus trafficking of membrane proteins such as receptors and channels. The Arabidopsis plant U-box (PUB) armadillo repeat (PUB-ARM) ubiquitin ligase SAUL1 (SENESCENCE-ASSOCIATED UBIQUITIN LIGASE1) is part of the ubiquitination machinery at the plasma membrane. In contrast to most other PUB-ARM proteins, SAUL1 carries additional C-terminal ARM repeats responsible for plasma membrane-association. Here, we demonstrated that the C-terminal ARM repeat domain is also essential and sufficient to mediate plasma membrane-association of the closest Arabidopis paralog AtPUB43. We investigated targeting of PUB-ARM ubiquitin ligases of different plant species to find out whether plasma membrane-association of SAUL1-type PUB-ARM proteins is conserved. Phylogenetic analysis identified orthologs of SAUL1 in these plant species. Intracellular localization of transiently expressed GFP fusion proteins revealed that indeed plasma membrane-association due to additional C-terminal ARM repeats represents a conserved feature of SAUL1-type proteins. Analyses of transgenic Arabidopsis plants overexpressing N-terminally masked or truncated proteins revealed that interfering with the function of SAUL1-type proteins resulted in severe growth defects. Our results suggest an ancient origin of ubiquitination at the plasma membrane in the evolution of land plants.
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Affiliation(s)
- Katja Vogelmann
- Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität HamburgHamburg, Germany
| | - Christa Subert
- Department Biologie, Molekulare Pflanzenphysiologie, Friedrich-Alexander-Universität Erlangen-NürnbergErlangen, Germany
| | - Nina Danzberger
- Department Biologie, Molekulare Pflanzenphysiologie, Friedrich-Alexander-Universität Erlangen-NürnbergErlangen, Germany
| | - Gabriele Drechsel
- Zentrum für Molekularbiologie der Pflanzen, Allgemeine Genetik, Universität TübingenTübingen, Germany
| | - Johannes Bergler
- Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität HamburgHamburg, Germany
| | - Tanja Kotur
- Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität HamburgHamburg, Germany
| | - Thorsten Burmester
- Stoffwechselphysiologie, Biozentrum Grindel, Universität HamburgHamburg, Germany
| | - Stefan Hoth
- Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität HamburgHamburg, Germany
- *Correspondence: Stefan Hoth, Molekulare Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, Ohnhorststrasse 18, D-22609 Hamburg, Germany e-mail:
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Gupta S, Bhar A, Das S. Understanding the molecular defence responses of host during chickpea-Fusarium interplay: where do we stand? FUNCTIONAL PLANT BIOLOGY : FPB 2013; 40:1285-1297. [PMID: 32481195 DOI: 10.1071/fp13063] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/04/2013] [Indexed: 06/11/2023]
Abstract
Fusarium oxysporum is known to cause vascular wilt and root rot of many important plants. Although extensive studies have been reported for the model plant Arabidopsis thaliana (L.) Heynh., the question of whether those experimental interpretations are extendable to other crop species requires experimentation. Chickpea is the most important crop legume of Indian subcontinent and ranks third in the world list of important legumes. However, productivity of this crop is severely curtailed by vascular wilt caused by Fusarium oxysporum f. sp. ciceri. Based on earlier reports, the present review discusses about the external manifestations of the disease, in planta fungal progression and establishment, and the molecular responses of chickpea that occur during Fusarium oxysporum f. sp. ciceri Race 1(Foc1) interaction. Foc1, known to enter the roots through the breaches of tap root, colonise the xylem vessels and block upward translocation of essential solutes causing wilt in compatible hosts. In contrast, pathogen invasion is readily perceived by the resistant host, which activates defence signalling cascades that are directed towards protecting its primary metabolism from the harmful consequences of pathogenic mayhem. Hence, understanding the dynamic complexities of chickpea-Foc1 interplay is prerequisite to providing sustainable solutions in wilt management programs.
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Affiliation(s)
- Sumanti Gupta
- Division of Plant Biology, Bose Institute, Centenary Campus, P1/12, CIT Scheme, VII-M, Kankurgachi, Kolkata-700054, West Bengal, India
| | - Anirban Bhar
- Division of Plant Biology, Bose Institute, Centenary Campus, P1/12, CIT Scheme, VII-M, Kankurgachi, Kolkata-700054, West Bengal, India
| | - Sampa Das
- Division of Plant Biology, Bose Institute, Centenary Campus, P1/12, CIT Scheme, VII-M, Kankurgachi, Kolkata-700054, West Bengal, India
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Ishizaki K, Mizutani M, Shimamura M, Masuda A, Nishihama R, Kohchi T. Essential role of the E3 ubiquitin ligase nopperabo1 in schizogenous intercellular space formation in the liverwort Marchantia polymorpha. THE PLANT CELL 2013; 25:4075-84. [PMID: 24170128 PMCID: PMC3877802 DOI: 10.1105/tpc.113.117051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/25/2013] [Accepted: 10/08/2013] [Indexed: 05/17/2023]
Abstract
The vast majority of land plants develop gas-exchange tissues with intercellular spaces (ICSs) connected directly to the air. Although the developmental processes of ICS have been described in detail at the morphological and ultrastructural level in diverse land plants, little is known about the molecular mechanism responsible for ICS formation. The liverwort Marchantia polymorpha develops a multilayered tissue with a large ICS (air chamber), whose formation is initiated at selected positions of epidermal cells. We isolated a mutant of M. polymorpha showing impaired air-chamber formation, nopperabo1 (nop1), from T-DNA-tagged lines. In nop1 plants, no ICS was formed; consequently, a single-layered epidermis developed on the dorsal side of the thallus. The causal gene NOP1 encodes a Plant U-box (PUB) E3 ubiquitin ligase carrying tandem ARMADILLO (ARM) repeats in the C terminus. An in vitro ubiquitination assay indicated that the NOP1 protein possesses E3 ubiquitin ligase activity in a U-box-dependent manner. Confocal microscopy and biochemical analysis showed that NOP1 was localized to the plasma membrane. Our investigation demonstrated the essential role of the PUB-ARM-type ubiquitin ligase in ICS formation in M. polymorpha, which sheds light on the molecular mechanism of schizogenous ICS formation in land plants.
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Affiliation(s)
- Kimitsune Ishizaki
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
- Graduate School of Science, Kobe University, Kobe 657-8501, Japan
| | - Miya Mizutani
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Masaki Shimamura
- Graduate School of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Akihide Masuda
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Ryuichi Nishihama
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
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Pommerrenig B, Popko J, Heilmann M, Schulmeister S, Dietel K, Schmitt B, Stadler R, Feussner I, Sauer N. SUCROSE TRANSPORTER 5 supplies Arabidopsis embryos with biotin and affects triacylglycerol accumulation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:392-404. [PMID: 23031218 PMCID: PMC3787789 DOI: 10.1111/tpj.12037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 08/22/2012] [Accepted: 09/24/2012] [Indexed: 05/18/2023]
Abstract
The Arabidopsis SUC5 protein represents a classical sucrose/H(+) symporter. Functional analyses previously revealed that SUC5 also transports biotin, an essential co-factor for fatty acid synthesis. However, evidence for a dual role in transport of the structurally unrelated compounds sucrose and biotin in plants was lacking. Here we show that SUC5 localizes to the plasma membrane, and that the SUC5 gene is expressed in developing embryos, confirming the role of the SUC5 protein as substrate carrier across apoplastic barriers in seeds. We show that transport of biotin but not of sucrose across these barriers is impaired in suc5 mutant embryos. In addition, we show that SUC5 is essential for the delivery of biotin into the embryo of biotin biosynthesis-defective mutants (bio1 and bio2). We compared embryo and seedling development as well as triacylglycerol accumulation and fatty acid composition in seeds of single mutants (suc5, bio1 or bio2), double mutants (suc5 bio1 and suc5 bio2) and wild-type plants. Although suc5 mutants were like the wild-type, bio1 and bio2 mutants showed developmental defects and reduced triacylglycerol contents. In suc5 bio1 and suc5 bio2 double mutants, developmental defects were severely increased and the triacylglycerol content was reduced to a greater extent in comparison to the single mutants. Supplementation with externally applied biotin helped to reduce symptoms in both single and double mutants, but the efficacy of supplementation was significantly lower in double than in single mutants, showing that transport of biotin into the embryo is lower in the absence of SUC5.
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Affiliation(s)
- Benjamin Pommerrenig
- Molekulare Pflanzenphysiologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstraße 5, D-91058, Erlangen, Germany.
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A U-Box E3 ubiquitin ligase, PUB20, interacts with the Arabidopsis G-protein β subunit, AGB1. PLoS One 2012; 7:e49207. [PMID: 23166612 PMCID: PMC3499536 DOI: 10.1371/journal.pone.0049207] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 10/07/2012] [Indexed: 11/20/2022] Open
Abstract
An Arabidopsis U-box E3 ubiquitin ligase Plant U-box 20 (PUB20; alternatively called AtCMPG1) was identified as a possible interactor of the Arabidopsis G-protein β subunit, AGB1, by yeast two-hybrid screening. A bimolecular fluorescence complementation (BiFC) assay showed that PUB20 interacted with AGB1 in the nuclei and the cytosol. The expression levels of PUB20 and its closest homolog, PUB21 were stable under many conditions. GUS driven by the PUB20 promoter was active in anthers, pollen, premature seeds and receptacles and GUS driven by the PUB21 promoter was active in anthers and funiculi. PUB20 was found to have autoubiquitination activity in vitro.
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Santos CS, Pinheiro M, Silva AI, Egas C, Vasconcelos MW. Searching for resistance genes to Bursaphelenchus xylophilus using high throughput screening. BMC Genomics 2012; 13:599. [PMID: 23134679 PMCID: PMC3542250 DOI: 10.1186/1471-2164-13-599] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 10/30/2012] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Pine wilt disease (PWD), caused by the pinewood nematode (PWN; Bursaphelenchus xylophilus), damages and kills pine trees and is causing serious economic damage worldwide. Although the ecological mechanism of infestation is well described, the plant's molecular response to the pathogen is not well known. This is due mainly to the lack of genomic information and the complexity of the disease. High throughput sequencing is now an efficient approach for detecting the expression of genes in non-model organisms, thus providing valuable information in spite of the lack of the genome sequence. In an attempt to unravel genes potentially involved in the pine defense against the pathogen, we hereby report the high throughput comparative sequence analysis of infested and non-infested stems of Pinus pinaster (very susceptible to PWN) and Pinus pinea (less susceptible to PWN). RESULTS Four cDNA libraries from infested and non-infested stems of P. pinaster and P. pinea were sequenced in a full 454 GS FLX run, producing a total of 2,083,698 reads. The putative amino acid sequences encoded by the assembled transcripts were annotated according to Gene Ontology, to assign Pinus contigs into Biological Processes, Cellular Components and Molecular Functions categories. Most of the annotated transcripts corresponded to Picea genes-25.4-39.7%, whereas a smaller percentage, matched Pinus genes, 1.8-12.8%, probably a consequence of more public genomic information available for Picea than for Pinus. The comparative transcriptome analysis showed that when P. pinaster was infested with PWN, the genes malate dehydrogenase, ABA, water deficit stress related genes and PAR1 were highly expressed, while in PWN-infested P. pinea, the highly expressed genes were ricin B-related lectin, and genes belonging to the SNARE and high mobility group families. Quantitative PCR experiments confirmed the differential gene expression between the two pine species. CONCLUSIONS Defense-related genes triggered by nematode infestation were detected in both P. pinaster and P. pinea transcriptomes utilizing 454 pyrosequencing technology. P. pinaster showed higher abundance of genes related to transcriptional regulation, terpenoid secondary metabolism (including some with nematicidal activity) and pathogen attack. P. pinea showed higher abundance of genes related to oxidative stress and higher levels of expression in general of stress responsive genes. This study provides essential information about the molecular defense mechanisms utilized by P. pinaster and P. pinea against PWN infestation and contributes to a better understanding of PWD.
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Affiliation(s)
- Carla S Santos
- CBQF – Centro de Biotecnologia e Química Fina, Escola Superior de Biotecnologia, Centro Regional do Porto da Universidade Católica Portuguesa, Rua Dr. António Bernardino Almeida, Porto, 4200-072, Portugal
| | - Miguel Pinheiro
- Bioinformatics Unit, Biocant, Parque Tecnológico de Cantanhede, Núcleo 04, Lote 03, Cantanhede, 3060-197, Portugal
| | - Ana I Silva
- CBQF – Centro de Biotecnologia e Química Fina, Escola Superior de Biotecnologia, Centro Regional do Porto da Universidade Católica Portuguesa, Rua Dr. António Bernardino Almeida, Porto, 4200-072, Portugal
| | - Conceição Egas
- Advanced Services Unit, Biocant, Parque Tecnológico de Cantanhede, Núcleo 04, Lote 03, Cantanhede, 3060-197, Portugal
| | - Marta W Vasconcelos
- CBQF – Centro de Biotecnologia e Química Fina, Escola Superior de Biotecnologia, Centro Regional do Porto da Universidade Católica Portuguesa, Rua Dr. António Bernardino Almeida, Porto, 4200-072, Portugal
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Guerra DD, Callis J. Ubiquitin on the move: the ubiquitin modification system plays diverse roles in the regulation of endoplasmic reticulum- and plasma membrane-localized proteins. PLANT PHYSIOLOGY 2012; 160:56-64. [PMID: 22730427 PMCID: PMC3440229 DOI: 10.1104/pp.112.199869] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
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Vogelmann K, Drechsel G, Bergler J, Subert C, Philippar K, Soll J, Engelmann JC, Engelsdorf T, Voll LM, Hoth S. Early senescence and cell death in Arabidopsis saul1 mutants involves the PAD4-dependent salicylic acid pathway. PLANT PHYSIOLOGY 2012; 159:1477-87. [PMID: 22706448 PMCID: PMC3425192 DOI: 10.1104/pp.112.196220] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 06/14/2012] [Indexed: 05/21/2023]
Abstract
Age-dependent leaf senescence and cell death in Arabidopsis (Arabidopsis thaliana) requires activation of the transcription factor ORESARA1 (ORE1) and is not initiated prior to a leaf age of 28 d. Here, we investigate the conditional execution of events that regulate early senescence and cell death in senescence-associated ubiquitin ligase1 (saul1) mutants, deficient in the PLANT U-BOX-ARMADILLO E3 ubiquitin ligase SAUL1. In saul1 mutants challenged with low light, the switch of age-dependent cell death was turned on prematurely, as indicated by the accumulation of ORE1 transcripts, induction of the senescence marker gene SENESCENCE-ASSOCIATED GENE12, and cell death. However, ORE1 accumulation by itself was not sufficient to cause saul1 phenotypes, as demonstrated by double mutant analysis. Exposure of saul1 mutants to low light for only 24 h did not result in visible symptoms of senescence; however, the senescence-promoting transcription factor genes WRKY53, WRKY6, and NAC-LIKE ACTIVATED BY AP3/PI were up-regulated, indicating that senescence in saul1 seedlings was already initiated. To resolve the time course of gene expression, microarray experiments were performed at narrow intervals. Differential expression of the genes involved in salicylic acid and defense mechanisms were the earliest events detected, suggesting a central role for salicylic acid in saul1 senescence and cell death. The salicylic acid content increased in low-light-treated saul1 mutants, and application of exogenous salicylic acid was indeed sufficient to trigger saul1 senescence in permissive light conditions. Double mutant analyses showed that PHYTOALEXIN DEFICIENT4 (PAD4) but not NONEXPRESSER OF PR GENES1 (NPR1) is essential for saul1 phenotypes. Our results indicate that saul1 senescence depends on the PAD4-dependent salicylic acid pathway but does not require NPR1 signaling.
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Wippel K, Sauer N. Arabidopsis SUC1 loads the phloem in suc2 mutants when expressed from the SUC2 promoter. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:669-79. [PMID: 22021573 PMCID: PMC3254675 DOI: 10.1093/jxb/err255] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 07/18/2011] [Accepted: 07/27/2011] [Indexed: 05/18/2023]
Abstract
Active loading of sucrose into phloem companion cells (CCs) is an essential process in apoplastic loaders, such as Arabidopsis or tobacco (Nicotiana sp.), and is even used by symplastic loaders such as melon (Cucumis melo) under certain stress conditions. Reduction of the amount or complete removal of the transporters catalysing this transport step results in severe developmental defects. Here we present analyses of two Arabidopsis lines, suc2-4 and suc2-5, that carry a null allele of the SUC2 gene which encodes the Arabidopsis phloem loader. These lines were complemented with constructs expressing either the Arabidopsis SUC1 or the Ustilago maydis srt1 cDNA from the SUC2 promoter. Both SUC1 and Srt1 are energy-dependent sucrose/H(+) symporters and differ in specific kinetic properties from the SUC2 protein. Transgene expression was confirmed by RT-PCRs, the subcellular localization of Srt1 in planta with an Srt1-RFP fusion, and the correct CC-specific localization of the recombinant proteins by immunolocalization with anti-Srt1 and anti-SUC1 antisera. The transport capacity of Srt1 was studied in Srt1-GFP expressing Arabidopsis protoplasts. Although both proteins were found exclusively in CCs, only SUC1 complemented the developmental defects of suc2-4 and suc2-5 mutants. As SUC1 and Srt1 are well characterized, this result provides an insight into the properties that are essential for sucrose transporters to load the phloem successfully.
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Affiliation(s)
- Kathrin Wippel
- Molekulare Pflanzenphysiologie, Universität Erlangen-Nürnberg, Staudtstraße 5, D-91058 Erlangen, Germany
| | - Norbert Sauer
- Molekulare Pflanzenphysiologie, Universität Erlangen-Nürnberg, Staudtstraße 5, D-91058 Erlangen, Germany
- Erlangen Center of Plant Science (ECROPS), Universität Erlangen-Nürnberg, Staudtstraße 5, D-91058 Erlangen, Germany
- To whom correspondence should be addressed. E-mail:
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Wolfenstetter S, Wirsching P, Dotzauer D, Schneider S, Sauer N. Routes to the tonoplast: the sorting of tonoplast transporters in Arabidopsis mesophyll protoplasts. THE PLANT CELL 2012; 24:215-32. [PMID: 22253225 PMCID: PMC3289566 DOI: 10.1105/tpc.111.090415] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 12/22/2011] [Accepted: 12/28/2011] [Indexed: 05/05/2023]
Abstract
Vacuoles perform a multitude of functions in plant cells, including the storage of amino acids and sugars. Tonoplast-localized transporters catalyze the import and release of these molecules. The mechanisms determining the targeting of these transporters to the tonoplast are largely unknown. Using the paralogous Arabidopsis thaliana inositol transporters INT1 (tonoplast) and INT4 (plasma membrane), we performed domain swapping and mutational analyses and identified a C-terminal di-leucine motif responsible for the sorting of higher plant INT1-type transporters to the tonoplast in Arabidopsis mesophyll protoplasts. We demonstrate that this motif can reroute other proteins, such as INT4, SUCROSE TRANSPORTER2 (SUC2), or SWEET1, to the tonoplast and that the position of the motif relative to the transmembrane helix is critical. Rerouted INT4 is functionally active in the tonoplast and complements the growth phenotype of an int1 mutant. In Arabidopsis plants defective in the β-subunit of the AP-3 adaptor complex, INT1 is correctly localized to the tonoplast, while sorting of the vacuolar sucrose transporter SUC4 is blocked in cis-Golgi stacks. Moreover, we demonstrate that both INT1 and SUC4 trafficking to the tonoplast is sensitive to brefeldin A. Our data show that plants possess at least two different Golgi-dependent targeting mechanisms for newly synthesized transporters to the tonoplast.
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Affiliation(s)
| | | | | | | | - Norbert Sauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Molecular Plant Physiology and ECROPS (Erlangen Center of Plant Science), D-91058 Erlangen, Germany
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Altered germination and subcellular localization patterns for PUB44/SAUL1 in response to stress and phytohormone treatments. PLoS One 2011; 6:e21321. [PMID: 21738636 PMCID: PMC3124495 DOI: 10.1371/journal.pone.0021321] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 05/24/2011] [Indexed: 11/25/2022] Open
Abstract
Background In plants, the ubiquitin-proteasome system is emerging as a significant regulatory system throughout the plant lifecycle. The ubiquitination of a target protein requires the sequential actions of the E1, E2 and E3 enzymes, with the latter E3 enzyme conferring target selection in this process. There are a large number of predicted E3 enzymes in plant genomes, and very little is known about the functions of many of these predicted genes. Here we report here an analysis of two closely-related members of the Arabidopsis Plant U-box (PUB) family of E3 ubiquitin ligases, PUB43 and PUB44. Principal Findings Homozygous pub44/pub44 mutant seedlings were found displayed a seedling lethal phenotype and this corresponded with widespread cell death lesions throughout the cotyledons and roots. Interestingly, heterozygous PUB44/pub44 seedlings were wild-type in appearance yet displayed intermediate levels of cell death lesions in comparison to pub44/pub44 seedlings. In contrast, homozygous pub43/pub43 mutants were viable and did not show any signs of cell death despite the PUB43 gene being more highly expressed than PUB44. The PUB44 mutants are not classical lesion mimic mutants as they did not have increased resistance to plant pathogens. We also observed increased germination rates in mutant seeds for both PUB44 and PUB43 under inhibitory concentrations of abscisic acid. Finally, the subcellular localization of PUB44 was investigated with transient expression assays in BY-2 cells. Under varying conditions, PUB44 was observed to be localized to the cytoplasm, plasma membrane, or nucleus. Conclusions Based on mutant plant analyses, the Arabidopsis PUB43 and PUB44 genes are proposed to function during seed germination and early seedling growth. Given PUB44's ability to shuttle from the nucleus to the plasma membrane, PUB44 may be active in different subcellular compartments as part of these biological functions.
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Salt JN, Yoshioka K, Moeder W, Goring DR. Altered germination and subcellular localization patterns for PUB44/SAUL1 in response to stress and phytohormone treatments. PLoS One 2011. [PMID: 21738636 DOI: 10.1371/journal.pone.0021321pone-d-11-06319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2023] Open
Abstract
BACKGROUND In plants, the ubiquitin-proteasome system is emerging as a significant regulatory system throughout the plant lifecycle. The ubiquitination of a target protein requires the sequential actions of the E1, E2 and E3 enzymes, with the latter E3 enzyme conferring target selection in this process. There are a large number of predicted E3 enzymes in plant genomes, and very little is known about the functions of many of these predicted genes. Here we report here an analysis of two closely-related members of the Arabidopsis Plant U-box (PUB) family of E3 ubiquitin ligases, PUB43 and PUB44. PRINCIPAL FINDINGS Homozygous pub44/pub44 mutant seedlings were found displayed a seedling lethal phenotype and this corresponded with widespread cell death lesions throughout the cotyledons and roots. Interestingly, heterozygous PUB44/pub44 seedlings were wild-type in appearance yet displayed intermediate levels of cell death lesions in comparison to pub44/pub44 seedlings. In contrast, homozygous pub43/pub43 mutants were viable and did not show any signs of cell death despite the PUB43 gene being more highly expressed than PUB44. The PUB44 mutants are not classical lesion mimic mutants as they did not have increased resistance to plant pathogens. We also observed increased germination rates in mutant seeds for both PUB44 and PUB43 under inhibitory concentrations of abscisic acid. Finally, the subcellular localization of PUB44 was investigated with transient expression assays in BY-2 cells. Under varying conditions, PUB44 was observed to be localized to the cytoplasm, plasma membrane, or nucleus. CONCLUSIONS Based on mutant plant analyses, the Arabidopsis PUB43 and PUB44 genes are proposed to function during seed germination and early seedling growth. Given PUB44's ability to shuttle from the nucleus to the plasma membrane, PUB44 may be active in different subcellular compartments as part of these biological functions.
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Affiliation(s)
- Jennifer N Salt
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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