Arabidopsis Endoplasmic Reticulum-Localized UBAC2 Proteins Interact with PAMP-INDUCED COILED-COIL to Regulate Pathogen-Induced Callose Deposition and Plant Immunity

The tubular network of the endoplasmic reticulum (ER) is formed by connecting ER tubules through three-way junctions. Two classes of the conserved ER membrane proteins, atlastins and lunapark, have been shown to reside at the three-way junctions so far and be involved in the generation and stabilization of the three-way junctions. In this study, we report TMCC3 (transmembrane and coiled-coil domain family 3), a member of the TEX28 family, as another ER membrane protein that resides at the three-way junctions in mammalian cells. When the TEX28 family members were transfected into U2OS cells, TMCC3 specifically localized at the three-way junctions in the peripheral ER. TMCC3 bound to atlastins through the C-terminal transmembrane domains. A TMCC3 mutant lacking the N-terminal coiled-coil domain abolished localization to the three-way junctions, suggesting that TMCC3 localized independently of binding to atlastins. TMCC3 knockdown caused a decrease in the number of three-way junctions and expansion of ER sheets, leading to a reduction of the tubular ER network in U2OS cells. The TMCC3 knockdown phenotype was partially rescued by the overexpression of atlastin-2, suggesting that TMCC3 knockdown would decrease the activity of atlastins. These results indicate that TMCC3 localizes at the three-way junctions for the proper tubular ER network.

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A vector system for fast-forward studies of the HOPZ-ACTIVATED RESISTANCE1 (ZAR1) resistosome in the model plant Nicotiana benthamiana

Plant Physiology ◽

10.1093/plphys/kiab471 ◽

2021 ◽

Author(s):

Adeline Harant ◽

Hsuan Pai ◽

Toshiyuki Sakai ◽

Sophien Kamoun ◽

Hiroaki Adachi

Keyword(s):

Nicotiana Benthamiana ◽

Cell Biology ◽

Plant Immunity ◽

Transient Gene Expression ◽

Coiled Coil ◽

Experimental System ◽

Vector System ◽

In Planta ◽

Functional Studies

Abstract Nicotiana benthamiana has emerged as a complementary experimental system to Arabidopsis thaliana. It enables fast-forward in vivo analyses primarily through transient gene expression and is particularly popular in the study of plant immunity. Recently, our understanding of nucleotide-binding leucine-rich repeat (NLR) plant immune receptors has greatly advanced following the discovery of the Arabidopsis HOPZ-ACTIVATED RESISTANCE1 (ZAR1) resistosome. Here, we describe a vector system of 72 plasmids that enables functional studies of the ZAR1 resistosome in N. benthamiana. We showed that ZAR1 stands out among the coiled coil class of NLRs (CC-NLRs) for being highly conserved across distantly related dicot plant species and confirmed NbZAR1 as the N. benthamiana ortholog of Arabidopsis ZAR1. Effector-activated and autoactive NbZAR1 trigger the cell death response in N. benthamiana and this activity is dependent on a functional N-terminal α1 helix. C-terminally tagged NbZAR1 remains functional in N. benthamiana, thus enabling cell biology and biochemical studies in this plant system. We conclude that the NbZAR1 open source pZA plasmid collection forms an additional experimental system to Arabidopsis for in planta resistosome studies.

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Bacillus amyloliquefaciens Strain PMB05 Intensifies Plant Immune Responses to Confer Resistance Against Bacterial Wilt of Tomato

Phytopathology ◽

10.1094/phyto-01-20-0026-r ◽

2020 ◽

Vol 110 (12) ◽

pp. 1877-1885

Author(s):

Ting-Hsin Ho ◽

Chiao-Yu Chuang ◽

Jing-Lin Zheng ◽

Hong-Hua Chen ◽

Yu-Shen Liang ◽

...

Keyword(s):

Disease Resistance ◽

Bacterial Wilt ◽

Bacillus Amyloliquefaciens ◽

Plant Immunity ◽

Reactive Oxygen Species Generation ◽

Soft Rot ◽

Limiting Factors ◽

Callose Deposition ◽

Bacillus Spp ◽

Tomato Bacterial Wilt

Tomato is an economic crop worldwide. Many limiting factors reduce the production of tomato, with bacterial wilt caused by Ralstonia solanacearum being the most destructive disease. Our previous study showed that the disease resistance to bacterial soft rot is enhanced by Bacillus amyloliquefaciens strain PMB05. This enhanced resistance is associated with the intensification of pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI). To determine whether the PTI-intensifying Bacillus spp. strains are able to confer disease resistance to bacterial wilt, their effects on PTI signals triggered by PAMP from R. solanacearum and on the occurrence of bacterial wilt were assayed. Before assay, a gene that encodes harpin from R. solanacearum, PopW, was applied as a PAMP. Results revealed that the B. amyloliquefaciens strain PMB05 was the one strain among 9 Bacillus rhizobacterial strains which could significantly intensify the PopW-induced hypersensitive response (HR) on Arabidopsis leaves. Moreover, we observed that the signals of PopW-induced reactive oxygen species generation and callose deposition were increased, confirming that the PTI was intensified by PMB05. The intensification of the PopW-triggered HR by PMB05 in Arabidopsis was reduced upon treatment with inhibitors in PTI pathways. Furthermore, the application of Bacillus spp. strains on tomato plants showed that only the use of PMB05 resulted in significantly increased resistance to bacterial wilt. Moreover, the PTI signals were also intensified in the tomato leaves. Taken together, we demonstrated that PMB05 is a PTI-intensifying bacterium that confers resistance to tomato bacterial wilt. Screening of plant immunity intensifying rhizobacteria is a possible strategy to control tomato bacterial wilt. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

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Changes in the plant endomembrane system associated with callose synthesis during the interaction between cowpea (Vigna unguiculata) and the cowpea rust fungus (Uromyces vignae)

Canadian Journal of Botany ◽

10.1139/b95-185 ◽

1995 ◽

Vol 73 (11) ◽

pp. 1731-1738 ◽

Cited By ~ 14

Author(s):

Dubravka Škalamera ◽

Michèle C. Heath

Keyword(s):

Endoplasmic Reticulum ◽

Vigna Unguiculata ◽

De Novo ◽

Rust Fungus ◽

Leaf Tissue ◽

Resistant Cultivar ◽

Callose Deposition ◽

Golgi Membranes ◽

Rough Er ◽

Uromyces Vignae

Electron microscopy and stereological analysis of cowpea (Vigna unguiculata) leaf tissue infected with the cowpea rust fungus (Uromyces vignae) revealed an increase in surface of plant endomembranes that was associated with callose synthesis or the presence of fungal haustoria. In the resistant cultivar in which the haustorium commonly becomes encased, an increase in surface of smooth membranes was observed in cytoplasmic regions adjacent to developing encasements compared with the regions away from the fungus or with any region in infected or uninfected callose nonsynthesizing cells. Cytoplasmic regions adjacent to the haustorium in callose nonsynthesizing cells had an increase in rough endoplasmic reticulum (ER). This increase was greater in a susceptible cultivar than in the resistant cultivar that was treated with tunicamycin to inhibit callose synthesis. In the latter situation, the lack of callose encasement allowed the haustorial neckband to form, but other ultrastructural signs of incompatibility remained, such as the presence of electron-opaque material associated with the extrahaustorial membrane. No differences between cultivars or treatments were observed in Golgi membranes. Our observations suggest that both callose synthesis and fungal presence are associated with de novo synthesis of membranes; callose deposition may require an increase in smooth membranes of uncertain origin, whereas the establishment of a haustorium may be dependent on increased synthesis of rough ER. Key words: callose, endoplasmic reticulum, resistance, stereology, tunicamycin.

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SVIP Is a Novel VCP/p97-interacting Protein Whose Expression Causes Cell Vacuolation

Molecular Biology of the Cell ◽

10.1091/mbc.02-07-0115 ◽

2003 ◽

Vol 14 (1) ◽

pp. 262-273 ◽

Cited By ~ 62

Author(s):

Masami Nagahama ◽

Mie Suzuki ◽

Yuko Hamada ◽

Kiyotaka Hatsuzawa ◽

Katsuko Tani ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Coiled Coil ◽

Adaptor Proteins ◽

Interacting Protein ◽

Cellular Processes ◽

Coiled Coil Region ◽

Acid Protein ◽

Extensive Cell ◽

Dependent Protein ◽

Amino Acid Protein

VCP/p97 is involved in a variety of cellular processes, including membrane fusion and ubiquitin-dependent protein degradation. It has been suggested that adaptor proteins such as p47 and Ufd1p confer functional versatility to VCP/p97. To identify novel adaptors, we searched for proteins that interact specifically with VCP/p97 by using the yeast two-hybrid system, and discovered a novel VCP/p97-interacting protein named smallVCP/p97-interactingprotein (SVIP). Rat SVIP is a 76-amino acid protein that contains two putative coiled-coil regions, and potential myristoylation and palmitoylation sites at the N terminus. Binding experiments revealed that the N-terminal coiled-coil region of SVIP, and the N-terminal and subsequent ATP-binding regions (ND1 domain) of VCP/p97, interact with each other. SVIP and previously identified adaptors p47 and ufd1p interact with VCP/p97 in a mutually exclusive manner. Overexpression of full-length SVIP or a truncated mutant did not markedly affect the structure of the Golgi apparatus, but caused extensive cell vacuolation reminiscent of that seen upon the expression of VCP/p97 mutants or polyglutamine proteins in neuronal cells. The vacuoles seemed to be derived from endoplasmic reticulum membranes. These results together suggest that SVIP is a novelVCP/p97 adaptor whose function is related to the integrity of the endoplasmic reticulum.

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Regulation of polysome assembly on the endoplasmic reticulum by a coiled-coil protein, p180

Nucleic Acids Research ◽

10.1093/nar/gkr1197 ◽

2011 ◽

Vol 40 (7) ◽

pp. 3006-3017 ◽

Cited By ~ 19

Author(s):

Tomonori Ueno ◽

Keiko Kaneko ◽

Tetsutaro Sata ◽

Shunji Hattori ◽

Kiyoko Ogawa-Goto

Keyword(s):

Endoplasmic Reticulum ◽

Coiled Coil

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Cucumber Mildew Resistance Locus O Interacts with Calmodulin and Regulates Plant Cell Death Associated with Plant Immunity

International Journal of Molecular Sciences ◽

10.3390/ijms20122995 ◽

2019 ◽

Vol 20 (12) ◽

pp. 2995 ◽

Cited By ~ 3

Author(s):

Guangchao Yu ◽

Xiangyu Wang ◽

Qiumin Chen ◽

Na Cui ◽

Yang Yu ◽

...

Keyword(s):

Cell Death ◽

Fluorescent Protein ◽

Plant Immunity ◽

Bimolecular Fluorescence Complementation ◽

Marker Genes ◽

Resistance Locus ◽

Callose Deposition ◽

Cucumis Sativus L ◽

Hypersensitive Cell Death ◽

Mildew Resistance

Pathogen-induced cell death is closely related to plant disease susceptibility and resistance. The cucumber (Cucumis sativus L.) mildew resistance locus O (CsMLO1) and calmodulin (CsCaM3) genes, as molecular components, are linked to nonhost resistance and hypersensitive cell death. In this study, we demonstrate that CsMLO1 interacts with CsCaM3 via yeast two-hybrid, firefly luciferase (LUC) complementation and bimolecular fluorescence complementation (BiFC) experiments. A subcellular localization analysis of green fluorescent protein (GFP) fusion reveals that CsCaM3 is transferred from the cytoplasm to the plasma membrane in Nicotiana benthamiana, and CsCaM3 green fluorescence is significantly attenuated via the coexpression of CsMLO1 and CsCaM3. CsMLO1 negatively regulates CsCaM3 expression in transiently transformed cucumbers, and hypersensitive cell death is disrupted by CsCaM3 and/or CsMLO1 expression under Corynespora cassiicola infection. Additionally, CsMLO1 silencing significantly enhances the expression of reactive oxygen species (ROS)-related genes (CsPO1, CsRbohD, and CsRbohF), defense marker genes (CsPR1 and CsPR3) and callose deposition-related gene (CsGSL) in infected cucumbers. These results suggest that the interaction of CsMLO1 with CsCaM3 may act as a cell death regulator associated with plant immunity and disease.

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HbLFG1, a rubber tree (Hevea brasiliensis) lifeguard protein, can facilitate powdery mildew infection by regulating plant immunity

Phytopathology ◽

10.1094/phyto-08-20-0362-r ◽

2021 ◽

Author(s):

Xiao Li ◽

Sipeng Li ◽

Yuhan Liu ◽

Qiguang He ◽

Wenbo Liu ◽

...

Keyword(s):

Powdery Mildew ◽

Host Plant ◽

Hevea Brasiliensis ◽

Plant Immunity ◽

Rubber Tree ◽

Negative Regulator ◽

Economic Plant ◽

Callose Deposition ◽

Erysiphe Quercicola ◽

Powdery Mildew Infection

Powdery mildew causes substantial losses in crop and economic plant yields worldwide. Although powdery mildew infection of rubber trees (Hevea brasiliensis), caused by the biotrophic fungus Erysiphe quercicola, severely threatens natural rubber production, little is known regarding the mechanism by which E. quercicola adapts to H. brasiliensis to invade the host plant. In barley and Arabidopsis thaliana, lifeguard (LFG) proteins, which have topological similarity to BAX INHIBITOR-1, are involved in host plant susceptibility to powdery mildew infection. In this study, we characterized an H. brasiliensis LFG protein, HbLFG1, with a focus on its function in regulating defence against powdery mildew. HbLFG1 gene expression was found to be upregulated during E. quercicola infection. HbLFG1 showed conserved functions in cell death inhibition and membrane localization. Expression of HbLFG1 in Nicotiana benthamiana leaves and A. thaliana Col-0 was demonstrated to significantly suppress callose deposition induced by conserved pathogen-associated molecular patterns chitin and flg22. Furthermore, we found that overexpression of HbLFG1 in H. brasiliensis mesophyll protoplasts significantly suppressed the chitin-induced burst of reactive oxygen species. Although A. thaliana Col-0 and E. quercicola displayed an incompatible interaction, Col-0 transformants overexpressing HbLFG1 were shown to be susceptible to E. quercicola. Collectively, the findings of this study provide evidence that HbLFG1 acts as a negative regulator of plant immunity that facilitates E. quercicola infection in H. brasiliensis.

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