The E3 Ubiquitin Ligase Activity of <i>Arabidopsis</i> PLANT U-BOX17 and Its Functional Tobacco Homolog ACRE276 Are Required for Cell Death and Defense

Yang, Chengwei; González-Lamothe, Rocío; Ewan, Richard; Rowland, Owen; Yoshioka, Hirofumi; Shenton, Matthew R.; Ye, Heng; O’Donnell, Elizabeth; Jones, Jonathan D. G.; Sadanandom, Ari

doi:10.1105/tpc.105.039198

Cited by 218 publications

(218 citation statements)

References 66 publications

(89 reference statements)

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“…These effects were not seen with similar alterations in PUB22 and PUB23, indicating some specificity, however pub22 pub23 double mutant plants were more drought resistant, but possibly through a different mechanism (Seo et al, 2012). PUB17 (At1g29340) appears to be the functional homolog of tomato ACRE276 based on transient disease assays using tobacco (Yang et al, 2006). While wild-type tobacco leaves exhibit a hypersensitive response after infiltration with Avr9 peptide, ACRE276-silenced stable tobacco leaves do not.…”

Section: U Box E3smentioning

confidence: 92%

The Ubiquitination Machinery of the Ubiquitin System

Callis

2014

The Arabidopsis Book

293

269

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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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Section: U Box E3smentioning

confidence: 92%

The Ubiquitination Machinery of the Ubiquitin System

Callis

2014

The Arabidopsis Book

293

269

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“…This suggests a role for the ubiquitination system as a negative regulator in the control of cell death and pathogen defense in rice plants (Zeng et al, 2004). On the other hand, the two most recent studies implicate tobacco U-box E3 Ub ligase NtCMPG1 and tobacco ACRE276 and its functional homolog Arabidopsis AtPUB17, respectively, as essential positive mediators for plant defense and disease resistance Yang et al, 2006). These results prompted us to create transgenic Arabidopsis plants that constitutively expressed the hot pepper CaPUB1 gene (Fig.…”

Section: Discussionmentioning

confidence: 99%

Heterologous Expression and Molecular and Cellular Characterization of CaPUB1 Encoding a Hot Pepper U-Box E3 Ubiquitin Ligase Homolog

et al. 2006

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The U-box motif is a conserved domain found in the diverse isoforms of E3 ubiquitin ligase in eukaryotes. From water-stressed hot pepper (Capsicum annuum L. cv Pukang) plants, we isolated C. annuum putative U-box protein 1 (CaPUB1), which encodes a protein containing a single U-box motif in its N-terminal region. In vitro ubiquitination and site-directed mutagenesis assays revealed that CaPUB1 possessed E3 ubiquitin ligase activity and that the U-box motif was indeed essential for its enzyme activity. RNA gel-blot analysis showed that CaPUB1 mRNA was induced rapidly by a broad spectrum of abiotic stresses, including drought, high salinity, cold temperature, and mechanical wounding, but not in response to ethylene, abscisic acid, or a bacterial pathogen, suggesting its role in the early events in the abiotic-related defense response. Because transgenic work was extremely difficult in hot pepper, in this study we overexpressed CaPUB1 in Arabidopsis (Arabidopsis thaliana) to provide cellular information on the function of this gene in the development and plant responses to abiotic stresses. Transgenic Arabidopsis plants that constitutively expressed the CaPUB1 gene under the control of the cauliflower mosaic virus 35S promoter had markedly longer hypocotyls and roots and grew more rapidly than the wild type, leading to an early bolting phenotype. Microscopic analysis showed that 35STCaPUB1 roots had increased numbers of small-sized cells, resulting in disordered, highly populated cell layers in the cortex, endodermis, and stele. In addition, CaPUB1-overexpressing plants displayed increased sensitivity to water stress and mild salinity. These results indicate that CaPUB1 is functional in Arabidopsis cells, thereby effectively altering cell and tissue growth and also the response to abiotic stresses. Comparative proteomic analysis showed that the level of RPN6 protein, a non-ATPase subunit of the 26S proteasome complex, was significantly reduced in 35STCaPUB1 seedlings as compared to the wild type. Pull-down and ubiquitination assays demonstrated that RPN6 interacted physically with CaPUB1 and was ubiquitinated in a CaPUB1-dependent manner in vitro. Although the physiological function of CaPUB1 is not yet clear, there are several possibilities for its involvement in a subset of physiological responses to counteract dehydration and high-salinity stresses in transgenic Arabidopsis seedlings.

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“…The discovery that AvrPtoB targets the host ubiquitin system highlights the importance of the ubiquitin pathway in disease resistance and cell death. Indeed, several recent papers show that plant U-box E3 ubiquitin ligases regulate plant cell death and immunity [96][97][98] . 42,76 .…”

Section: Bacterial Suppression Of Hr-based Pcdmentioning

confidence: 99%

Bacterial elicitation and evasion of plant innate immunity

Abramovitch

Anderson

Martin

2006

Nat Rev Mol Cell Biol

377

285

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Recent research on plant responses to bacterial attack has identified extracellular and intracellular host receptors that recognize conserved pathogen-associated molecular patterns and more specialized virulence proteins, respectively. These findings have shed light on our understanding of the molecular mechanisms by which bacteria elicit host defences and how pathogens have evolved to evade or suppress these defences.Plants are a rich source of nutrients and water for microbes, and they are infected by many bacterial pathogens from both the Proteobacteria and Actinobacteria phyla (Supplementary information 1 (table)). Because of their broad host range, serious economic consequences and experimental tractability, the most intensively studied bacteria are members of the Proteobacteria phylum (such as Agrobacterium, Erwinia, Pseudomonas, Ralstonia and Xanthomonas) [1][2][3][4] . These pathogens are spread by wind, rain, insects or cultivation practices. They enter plant tissues either by wounds or through natural openings such as lenticels, hydathodes or stomata 5 , and they occupy the inter cellular spaces (apoplast) of various plant tissues or the xylem.Plant-pathogenic members of the Proteobacteria cause diverse disease symptoms, including specks, spots, blights, wilts, galls and cankers, and they can cause host-cell death in roots, leaves, flowers, fruits, stems and tubers (FIG. 1). These symptoms affect both yield and quality of agricultural crops and bacterial diseases can have serious economic, social and even political consequences [6][7][8] . Control of bacterial diseases is only partially effective and consists of copper-based sprays, antibiotics, biocontrol strategies, large-scale removal of infected plants and, most importantly, host genetic resistance 5 . Therefore, research on bacterial diseases of plants helps to elucidate fundamental aspects of microbial pathogenesis and associated host responses and also to develop more effective and sustainable disease-control methods.Correspondence to G.B.M. gbm7@cornell.edu. Competing interests statementThe authors declare no competing financial interests. DATABASES NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptPlant-pathogenic bacteria use virulence strategies that are either specialized to plant tissues or are broadly conserved among pathogens of both plants and animals (FIG. 1). Bacterial virulence is manifested as increases in the rate of growth or final population size, as well as by enhanced disease symptoms, which promote the spread of the pathogen through the plant or the broader environment.Unlike mammals, plants have a complex cell wall that bacteria must surmount to gain access to water and nutrients. Bacteria attack this barrier with extracellular virulence factors, such as cell wall degrading enzymes, and bypass it by the secretion of cell wall-permeable toxins 5 . However, perhaps the most effective virulence strategy, and one shared with animal bacterial pathogens, is to breach the wall by use of the type III s...

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The E3 Ubiquitin Ligase Activity of Arabidopsis PLANT U-BOX17 and Its Functional Tobacco Homolog ACRE276 Are Required for Cell Death and Defense

Cited by 218 publications

References 66 publications

The Ubiquitination Machinery of the Ubiquitin System

The Ubiquitination Machinery of the Ubiquitin System

Heterologous Expression and Molecular and Cellular Characterization of CaPUB1 Encoding a Hot Pepper U-Box E3 Ubiquitin Ligase Homolog

Bacterial elicitation and evasion of plant innate immunity

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