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Li Y, Wang Q, Jia H, Ishikawa K, Kosami KI, Ueba T, Tsujimoto A, Yamanaka M, Yabumoto Y, Miki D, Sasaki E, Fukao Y, Fujiwara M, Kaneko-Kawano T, Tan L, Kojima C, Wing RA, Sebastian A, Nishimura H, Fukada F, Niu Q, Shimizu M, Yoshida K, Terauchi R, Shimamoto K, Kawano Y. An NLR paralog Pit2 generated from tandem duplication of Pit1 fine-tunes Pit1 localization and function. Nat Commun 2024; 15:4610. [PMID: 38816417 PMCID: PMC11139913 DOI: 10.1038/s41467-024-48943-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 05/17/2024] [Indexed: 06/01/2024] Open
Abstract
NLR family proteins act as intracellular receptors. Gene duplication amplifies the number of NLR genes, and subsequent mutations occasionally provide modifications to the second gene that benefits immunity. However, evolutionary processes after gene duplication and functional relationships between duplicated NLRs remain largely unclear. Here, we report that the rice NLR protein Pit1 is associated with its paralogue Pit2. The two are required for the resistance to rice blast fungus but have different functions: Pit1 induces cell death, while Pit2 competitively suppresses Pit1-mediated cell death. During evolution, the suppression of Pit1 by Pit2 was probably generated through positive selection on two fate-determining residues in the NB-ARC domain of Pit2, which account for functional differences between Pit1 and Pit2. Consequently, Pit2 lost its plasma membrane localization but acquired a new function to interfere with Pit1 in the cytosol. These findings illuminate the evolutionary trajectory of tandemly duplicated NLR genes after gene duplication.
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Affiliation(s)
- Yuying Li
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Qiong Wang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
- College of Plant Protection, Yangzhou University, Yangzhou, 225009, China
| | - Huimin Jia
- College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, Jiangxi, China
| | - Kazuya Ishikawa
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
- College of Life Sciences, Ritsumeikan University, Kusatsu, 525-8577, Japan
| | - Ken-Ichi Kosami
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
- Fruit Tree Research Center, Ehime Research Institute of Agriculture, Forestry and Fisheries, Ehime, 791-0112, Japan
| | - Takahiro Ueba
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Nara, 630-0101, Japan
| | - Atsumi Tsujimoto
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Nara, 630-0101, Japan
| | - Miki Yamanaka
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Nara, 630-0101, Japan
| | - Yasuyuki Yabumoto
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Nara, 630-0101, Japan
| | - Daisuke Miki
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Eriko Sasaki
- Faculty of Science, Kyushu University, Fukuoka, 819-0395, Japan
| | - Yoichiro Fukao
- Department of Bioinformatics, Ritsumeikan University, Shiga, 525-8577, Japan
| | | | - Takako Kaneko-Kawano
- College of Pharmaceutical Sciences, Ritsumeikan University, Shiga, 525-8577, Japan
| | - Li Tan
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Chojiro Kojima
- Graduate School of Engineering Science, Yokohama National University, Yokohama, Kanagawa, 240-8501, Japan
| | - Rod A Wing
- Arizona Genomics Institute, School of Plant Sciences, University of Arizona, Tucson, AZ, USA
| | - Alfino Sebastian
- Institute of Plant Science and Resources, Okayama University, Okayama, 710-0046, Japan
| | - Hideki Nishimura
- Institute of Plant Science and Resources, Okayama University, Okayama, 710-0046, Japan
| | - Fumi Fukada
- Institute of Plant Science and Resources, Okayama University, Okayama, 710-0046, Japan
| | - Qingfeng Niu
- Advanced Academy, Anhui Agricultural University, Research Centre for Biological Breeding Technology, Hefei, Anhui, 230036, China
| | - Motoki Shimizu
- Iwate Biotechnology Research Center, Iwate, 024-0003, Japan
| | - Kentaro Yoshida
- Graduate School of Agriculture, Kyoto University, Kyoto, 617-0001, Japan
| | - Ryohei Terauchi
- Iwate Biotechnology Research Center, Iwate, 024-0003, Japan
- Graduate School of Agriculture, Kyoto University, Kyoto, 617-0001, Japan
| | - Ko Shimamoto
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Nara, 630-0101, Japan
| | - Yoji Kawano
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China.
- Institute of Plant Science and Resources, Okayama University, Okayama, 710-0046, Japan.
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Kanagawa, 244-0813, Japan.
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Trutzenberg A, Engelhardt S, Weiß L, Hückelhoven R. Barley guanine nucleotide exchange factor HvGEF14 is an activator of the susceptibility factor HvRACB and supports host cell entry by Blumeria graminis f. sp. hordei. MOLECULAR PLANT PATHOLOGY 2022; 23:1524-1537. [PMID: 35849420 PMCID: PMC9452760 DOI: 10.1111/mpp.13246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/31/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
In barley (Hordeum vulgare), signalling rat sarcoma homolog (RHO) of plants guanosine triphosphate hydrolases (ROP GTPases) support the penetration success of Blumeria graminis f. sp. hordei but little is known about ROP activation. Guanine nucleotide exchange factors (GEFs) facilitate the exchange of ROP-bound GDP for GTP and thereby turn ROPs into a signalling-activated ROP-GTP state. Plants possess a unique class of GEFs harbouring a plant-specific ROP nucleotide exchanger domain (PRONE). Here, we performed phylogenetic analyses and annotated barley PRONE-GEFs. The leaf epidermal-expressed PRONE-GEF HvGEF14 undergoes a transcriptional down-regulation on inoculation with B. graminis f. sp. hordei and directly interacts with the ROP GTPase and susceptibility factor HvRACB in yeast and in planta. Overexpression of activated HvRACB or of HvGEF14 led to the recruitment of ROP downstream interactor HvRIC171 to the cell periphery. HvGEF14 further supported direct interaction of HvRACB with a HvRACB-GTP-binding CRIB (Cdc42/Rac Interactive Binding motif) domain-containing HvRIC171 truncation. Finally, the overexpression of HvGEF14 caused enhanced susceptibility to fungal entry, while HvGEF14 RNAi provoked a trend to more penetration resistance. HvGEF14 might therefore play a role in the activation of HvRACB in barley epidermal cells during fungal penetration.
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Affiliation(s)
- Adriana Trutzenberg
- Chair of Phytopathology, School of Life SciencesTechnical University of MunichFreising‐WeihenstephanGermany
| | - Stefan Engelhardt
- Chair of Phytopathology, School of Life SciencesTechnical University of MunichFreising‐WeihenstephanGermany
| | - Lukas Weiß
- Chair of Phytopathology, School of Life SciencesTechnical University of MunichFreising‐WeihenstephanGermany
| | - Ralph Hückelhoven
- Chair of Phytopathology, School of Life SciencesTechnical University of MunichFreising‐WeihenstephanGermany
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3
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Wang Q, Li Y, Kosami KI, Liu C, Li J, Zhang D, Miki D, Kawano Y. Three highly conserved hydrophobic residues in the predicted α2-helix of rice NLR protein Pit contribute to its localization and immune induction. PLANT, CELL & ENVIRONMENT 2022; 45:1876-1890. [PMID: 35312080 DOI: 10.1111/pce.14315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 02/20/2022] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Nucleotide-binding leucine-rich repeat (NLR) proteins work as crucial intracellular immune receptors. N-terminal domains of NLRs fall into two groups, coiled-coil (CC) and Toll-interleukin 1 receptor domains, which play critical roles in signal transduction and disease resistance. However, the activation mechanisms of NLRs, and how their N-termini function in immune induction, remain largely unknown. Here, we revealed that the CC domain of a rice NLR Pit contributes to self-association. The Pit CC domain possesses three conserved hydrophobic residues that are known to be involved in oligomer formation in two NLRs, barley MLA10 and Arabidopsis RPM1. Interestingly, the function of these residues in Pit differs from that in MLA10 and RPM1. Although three hydrophobic residues are important for Pit-induced disease resistance against rice blast fungus, they do not participate in self-association or binding to downstream signalling molecules. By homology modelling of Pit using the Arabidopsis ZAR1 structure, we tried to clarify the role of three conserved hydrophobic residues and found that they are located in the predicted α2-helix of the Pit CC domain and involved in the plasma membrane localization. Our findings provide novel insights for understanding the mechanisms of NLR activation as well as the relationship between subcellular localization and immune induction.
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Affiliation(s)
- Qiong Wang
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
| | - Yuying Li
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
- Lingnan Guangdong Laboratory of Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Ken-Ichi Kosami
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
- Fruit Tree Research Center, Ehime Research Institute of Agriculture, Forestry and Fisheries, Ehime, Japan
| | - Chaochao Liu
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Jing Li
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Dan Zhang
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Daisuke Miki
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
| | - Yoji Kawano
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
- Kihara Institute for Biological Research, Yokohama City University, Kanagawa, Japan
- Institute of Plant Science and Resources, Okayama University, Okayama, Japan
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4
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Akamatsu A, Fujiwara M, Hamada S, Wakabayashi M, Yao A, Wang Q, Kosami KI, Dang TT, Kaneko-Kawano T, Fukada F, Shimamoto K, Kawano Y. The Small GTPase OsRac1 Forms Two Distinct Immune Receptor Complexes Containing the PRR OsCERK1 and the NLR Pit. PLANT & CELL PHYSIOLOGY 2021; 62:1662-1675. [PMID: 34329461 DOI: 10.1093/pcp/pcab121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
Plants employ two different types of immune receptors, cell surface pattern recognition receptors (PRRs) and intracellular nucleotide-binding and leucine-rich repeat-containing proteins (NLRs), to cope with pathogen invasion. Both immune receptors often share similar downstream components and responses but it remains unknown whether a PRR and an NLR assemble into the same protein complex or two distinct receptor complexes. We have previously found that the small GTPase OsRac1 plays key roles in the signaling of OsCERK1, a PRR for fungal chitin, and of Pit, an NLR for rice blast fungus, and associates directly and indirectly with both of these immune receptors. In this study, using biochemical and bioimaging approaches, we revealed that OsRac1 formed two distinct receptor complexes with OsCERK1 and with Pit. Supporting this result, OsCERK1 and Pit utilized different transport systems for anchorage to the plasma membrane (PM). Activation of OsCERK1 and Pit led to OsRac1 activation and, concomitantly, OsRac1 shifted from a small to a large protein complex fraction. We also found that the chaperone Hsp90 contributed to the proper transport of Pit to the PM and the immune induction of Pit. These findings illuminate how the PRR OsCERK1 and the NLR Pit orchestrate rice immunity through the small GTPase OsRac1.
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Affiliation(s)
- Akira Akamatsu
- Department of Biosciences, Kwansei Gakuin University, 2-1 Gakuen, Hyogo, 669-1337, Japan
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Masayuki Fujiwara
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
- Yanmar Holdings Co., Ltd, 1-32 Chayamachi, Kita Ward, Osaka 530-8311, Japan
| | - Satoshi Hamada
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Megumi Wakabayashi
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
- Field Solutions North East Asia, Agronomic Operations Japan, Agronomic Technology Station East Japan, Bayer Crop Science K.K., 9511-4 Yuki, Ibaraki 307-0001, Japan
| | - Ai Yao
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Qiong Wang
- Department of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Ken-Ichi Kosami
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, No. 3888 Chenhua Road, Shanghai 201602, China
- Fruit Tree Research Center, Ehime Research Institute of Agriculture, Forestry and Fisheries, Matsuyama, 1618 Shimoidaicho, Ehime 791-0112, Japan
| | - Thu Thi Dang
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, No. 3888 Chenhua Road, Shanghai 201602, China
- IRHS-UMR1345, INRAE, Institut Agro, SFR 4207 QuaSaV, Université d'Angers, Beaucouzé 49071, France
| | - Takako Kaneko-Kawano
- College of Pharmaceutical Sciences, Ritsumeikan University, 1 Chome-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
| | - Fumi Fukada
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan
| | - Ko Shimamoto
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Yoji Kawano
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, No. 3888 Chenhua Road, Shanghai 201602, China
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maiokachō, Totsuka Ward, Yokohama, Kanagawa 244-0813, Japan
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5
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Kim EJ, Hong WJ, Tun W, An G, Kim ST, Kim YJ, Jung KH. Interaction of OsRopGEF3 Protein With OsRac3 to Regulate Root Hair Elongation and Reactive Oxygen Species Formation in Rice ( Oryza sativa). FRONTIERS IN PLANT SCIENCE 2021; 12:661352. [PMID: 34113363 PMCID: PMC8185220 DOI: 10.3389/fpls.2021.661352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/14/2021] [Indexed: 06/12/2023]
Abstract
Root hairs are tip-growing cells that emerge from the root epidermis and play a role in water and nutrient uptake. One of the key signaling steps for polar cell elongation is the formation of Rho-GTP by accelerating the intrinsic exchange activity of the Rho-of-plant (ROP) or the Rac GTPase protein; this step is activated through the interaction with the plant Rho guanine nucleotide exchange factor (RopGEFs). The molecular players involved in root hair growth in rice are largely unknown. Here, we performed the functional analysis of OsRopGEF3, which is highly expressed in the root hair tissues among the OsRopGEF family genes in rice. To reveal the role of OsRopGEF3, we analyzed the phenotype of loss-of-function mutants of OsRopGEF3, which were generated using the CRISPR-Cas9 system. The mutants had reduced root hair length and increased root hair width. In addition, we confirmed that reactive oxygen species (ROS) were highly reduced in the root hairs of the osropgef3 mutant. The pairwise yeast two-hybrid experiments between OsRopGEF3 and OsROP/Rac proteins in rice revealed that the OsRopGEF3 protein interacts with OsRac3. This interaction and colocalization at the same subcellular organelles were again verified in tobacco leaf cells and rice root protoplasts via bimolecular functional complementation (BiFC) assay. Furthermore, among the three respiratory burst oxidase homolog (OsRBOH) genes that are highly expressed in rice root hair cells, we found that OsRBOH5 can interact with OsRac3. Our results demonstrate an interaction network model wherein OsRopGEF3 converts the GDP of OsRac3 into GTP, and OsRac3-GTP then interacts with the N-terminal of OsRBOH5 to produce ROS, thereby suggesting OsRopGEF3 as a key regulating factor in rice root hair growth.
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Affiliation(s)
- Eui-Jung Kim
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, South Korea
| | - Woo-Jong Hong
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, South Korea
| | - Win Tun
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, South Korea
| | - Gynheung An
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, South Korea
| | - Sun-Tae Kim
- Department of Plant Bioscience, Pusan National University, Miryang, South Korea
| | - Yu-Jin Kim
- Department of Life Science and Environmental Biochemistry, and Life and Industry Convergence Research Institute, Pusan National University, Miryang, South Korea
| | - Ki-Hong Jung
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, South Korea
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6
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Rawat N, Singla-Pareek SL, Pareek A. Membrane dynamics during individual and combined abiotic stresses in plants and tools to study the same. PHYSIOLOGIA PLANTARUM 2021; 171:653-676. [PMID: 32949408 DOI: 10.1111/ppl.13217] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/25/2020] [Accepted: 09/13/2020] [Indexed: 05/15/2023]
Abstract
The plasma membrane (PM) is possibly the most diverse biological membrane of plant cells; it separates and guards the cell against its external environment. It has an extremely complex structure comprising a mosaic of lipids and proteins. The PM lipids are responsible for maintaining fluidity, permeability and integrity of the membrane and also influence the functioning of membrane proteins. However, the PM is the primary target of environmental stress, which affects its composition, conformation and properties, thereby disturbing the cellular homeostasis. Maintenance of integrity and fluidity of the PM is a prerequisite for ensuring the survival of plants during adverse environmental conditions. The ability of plants to remodel membrane lipid and protein composition plays a crucial role in adaptation towards varying abiotic environmental cues, including high or low temperature, drought, salinity and heavy metals stress. The dynamic changes in lipid composition affect the functioning of membrane transporters and ultimately regulate the physical properties of the membrane. Plant membrane-transport systems play a significant role in stress adaptation by cooperating with the membrane lipidome to maintain the membrane integrity under stressful conditions. The present review provides a holistic view of stress responses and adaptations in plants, especially the changes in the lipidome and proteome of PM under individual or combined abiotic stresses, which cause alterations in the activity of membrane transporters and modifies the fluidity of the PM. The tools to study the varying lipidome and proteome of the PM are also discussed.
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Affiliation(s)
- Nishtha Rawat
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sneh L Singla-Pareek
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Road, New Delhi, 110067, India
| | - Ashwani Pareek
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
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7
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Cheng X, Mwaura BW, Chang Stauffer SR, Bezanilla M. A Fully Functional ROP Fluorescent Fusion Protein Reveals Roles for This GTPase in Subcellular and Tissue-Level Patterning. THE PLANT CELL 2020; 32:3436-3451. [PMID: 32917738 PMCID: PMC7610296 DOI: 10.1105/tpc.20.00440] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/25/2020] [Accepted: 09/07/2020] [Indexed: 05/18/2023]
Abstract
Rho of Plants (ROPs) are GTPases that regulate polarity and patterned wall deposition in plants. As these small, globular proteins have many interactors, it has been difficult to ensure that methods to visualize ROP in live cells do not affect ROP function. Here, motivated by work in fission yeast (Schizosaccharomyces pombe), we generated a fluorescent moss (Physcomitrium [Physcomitrella] patens) ROP4 fusion protein by inserting mNeonGreen after Gly-134. Plants harboring tagged ROP4 and no other ROP genes were phenotypically normal. Plants lacking all four ROP genes comprised an unpatterned clump of spherical cells that were unable to form gametophores, demonstrating that ROP is essentially for spatial patterning at the cellular and tissue levels. The functional ROP fusion protein formed a steep gradient at the apical plasma membranes of growing tip cells. ROP also predicted the site of branch formation in the apical cell at the onset of mitosis, which occurs one to two cell cycles before a branch cell emerges. While fluorescence recovery after photobleaching studies demonstrated that ROP dynamics do not depend on the cytoskeleton, acute depolymerization of the cytoskeleton removed ROP from the membrane only in recently divided cells, pointing to a feedback mechanism between the cell cycle, cytoskeleton, and ROP.
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Affiliation(s)
- Xiaohang Cheng
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
| | - Bethany W Mwaura
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
| | | | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
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8
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Le Bail A, Schulmeister S, Perroud PF, Ntefidou M, Rensing SA, Kost B. Analysis of the Localization of Fluorescent PpROP1 and PpROP-GEF4 Fusion Proteins in Moss Protonemata Based on Genomic "Knock-In" and Estradiol-Titratable Expression. FRONTIERS IN PLANT SCIENCE 2019; 10:456. [PMID: 31031790 PMCID: PMC6473103 DOI: 10.3389/fpls.2019.00456] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/26/2019] [Indexed: 05/26/2023]
Abstract
Tip growth of pollen tubes, root hairs, and apical cells of moss protonemata is controlled by ROP (Rho of plants) GTPases, which were shown to accumulate at the apical plasma membrane of these cells. However, most ROP localization patterns reported in the literature are based on fluorescent protein tagging and need to be interpreted with caution, as ROP fusion proteins were generally overexpressed at undefined levels, in many cases without assessing effects on tip growth. ROP-GEFs, important regulators of ROP activity, were also described to accumulate at the apical plasma membrane during tip growth. However, to date only the localization of fluorescent ROP-GEF fusion proteins strongly overexpressed using highly active promoters have been investigated. Here, the intracellular distributions of fluorescent PpROP1 and PpROP-GEF4 fusion proteins expressed at essentially endogenous levels in apical cells of Physcomitrella patens "knock-in" protonemata were analyzed. Whereas PpROP-GEF4 was found to associate with a small apical plasma membrane domain, PpROP1 expression was below the detection limit. Estradiol-titratable expression of a fluorescent PpROP1 fusion protein at the lowest detectable level, at which plant development was only marginally affected, was therefore employed to show that PpROP1 also accumulates at the apical plasma membrane, although within a substantially larger domain. Interestingly, RNA-Seq data indicated that the majority of all genes active in protonemata are expressed at lower levels than PpROP1, suggesting that estradiol-titratable expression may represent an important alternative to "knock-in" based analysis of the intracellular distribution of fluorescent fusion proteins in protonemal cells.
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Affiliation(s)
- Aude Le Bail
- Cell Biology, Department of Biology, Friedrich–Alexander University Erlangen–Nürnberg, Erlangen, Germany
| | - Sylwia Schulmeister
- Cell Biology, Department of Biology, Friedrich–Alexander University Erlangen–Nürnberg, Erlangen, Germany
| | | | - Maria Ntefidou
- Cell Biology, Department of Biology, Friedrich–Alexander University Erlangen–Nürnberg, Erlangen, Germany
| | - Stefan A. Rensing
- Plant Cell Biology, Faculty of Biology, Philipps University of Marburg, Marburg, Germany
| | - Benedikt Kost
- Cell Biology, Department of Biology, Friedrich–Alexander University Erlangen–Nürnberg, Erlangen, Germany
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9
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Rosquete MR, Drakakaki G. Plant TGN in the stress response: a compartmentalized overview. CURRENT OPINION IN PLANT BIOLOGY 2018; 46:122-129. [PMID: 30316189 DOI: 10.1016/j.pbi.2018.09.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Revised: 08/31/2018] [Accepted: 09/04/2018] [Indexed: 05/10/2023]
Abstract
The cellular responses to abiotic and biotic stress rely on the regulation of vesicle trafficking to ensure the correct localization of proteins specialized in sensing stress stimuli and effecting the response. Several studies have implicated the plant trans-Golgi network (TGN)-mediated trafficking in different types of biotic and abiotic stress responses; however, the underlying molecular mechanisms are poorly understood. Further, the identity, specialization and stress-relevant cargo transported by the TGN subcompartments involved in stress responses await more in depth characterization. This review presents TGN trafficking players implicated in stress and discusses potential avenues to understand the role of this dynamic network under such extreme circumstances.
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Affiliation(s)
- Michel Ruiz Rosquete
- Department of Plant Sciences, University of California, Davis, CA 95616, United States.
| | - Georgia Drakakaki
- Department of Plant Sciences, University of California, Davis, CA 95616, United States.
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10
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Resistance protein Pit interacts with the GEF OsSPK1 to activate OsRac1 and trigger rice immunity. Proc Natl Acad Sci U S A 2018; 115:E11551-E11560. [PMID: 30446614 DOI: 10.1073/pnas.1813058115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Resistance (R) genes encode intracellular nucleotide-binding/leucine-rich repeat-containing (NLR) family proteins that serve as critical plant immune receptors to induce effector-triggered immunity (ETI). NLR proteins possess a tripartite domain architecture consisting of an N-terminal variable region, a central nucleotide-binding domain, and a C-terminal leucine-rich repeat. N-terminal coiled-coil (CC) or Toll-interleukin 1 receptor (TIR) domains of R proteins appear to serve as platforms to trigger immune responses, because overexpression of the CC or TIR domain of some R proteins is sufficient to induce an immune response. Because direct downstream signaling molecules of R proteins remain obscure, the molecular mechanisms by which R proteins regulate downstream signaling are largely unknown. We reported previously that a rice R protein named Pit triggers ETI through a small GTPase, OsRac1, although how Pit activates OsRac1 is unclear. Here, we identified OsSPK1, a DOCK family guanine nucleotide exchange factor, as an interactor of Pit and activator for OsRac1. OsSPK1 contributes to signaling by two disease-resistance genes, Pit and Pia, against the rice blast fungus Magnaporthe oryzae and facilitates OsRac1 activation in vitro and in vivo. The CC domain of Pit is required for its binding to OsSPK1, OsRac1 activation, and the induction of cell death. Overall, we conclude that OsSPK1 is a direct and key signaling target of Pit-mediated immunity. Our results shed light on how R proteins trigger ETI through direct downstream molecules.
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