scholarly journals The Arabidopsis E3 ubiquitin ligase PUB4 regulates BIK1 homeostasis and is targeted by a bacterial type-III effector

2020 ◽  
Author(s):  
Maria Derkacheva ◽  
Gang Yu ◽  
Jose S. Rufian ◽  
Shushu Jiang ◽  
Paul Derbyshire ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Plant Immunity ◽  
E3 Ubiquitin Ligase ◽  
Bacterial Pathogen ◽  
Positive Role ◽  
Type Iii ◽  
Molecular Pattern ◽  
Pathogen Associated Molecular Pattern ◽  
Bacterial Type ◽  
Shed Light

SummaryPlant immunity is tightly controlled by a complex and dynamic regulatory network, which ensures optimal activation upon detection of potential pathogens. Accordingly, each component of this network is a potential target for manipulation by pathogens. Here, we report that RipAC, a type III-secreted effector from the bacterial pathogen Ralstonia solanacearum, targets the plant E3 ubiquitin ligase PUB4 to inhibit pattern-triggered immunity (PTI). PUB4 plays a positive role in PTI by regulating the homeostasis of the central immune kinase BIK1. Before PAMP perception, PUB4 promotes the degradation of non-activated BIK1, while, after PAMP perception, PUB4 contributes to the accumulation of activated BIK1. RipAC leads to BIK1 degradation, which correlates with its PTI-inhibitory activity. RipAC causes a reduction in pathogen-associated molecular pattern (PAMP)-induced PUB4 accumulation and phosphorylation. Our results shed light on the role played by PUB4 in immune regulation, and illustrate an indirect targeting of the immune signalling hub BIK1 by a bacterial effector.

scholarly journals AtPPRT1, an E3 Ubiquitin Ligase, Enhances the Thermotolerance in Arabidopsis

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1074
Author(s):  
Yu Liu ◽  
Shuya Xiao ◽  
Haoran Sun ◽  
Linsen Pei ◽  
Yingying Liu ◽  
...  
Keyword(s):  
Heat Stress ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Degradation Pathway ◽  
Vital Role ◽  
Loss Of Function ◽  
Positive Role ◽  
Heat Stress Response ◽  
Acquired Thermotolerance ◽  
Ubiquitin E3 Ligase

E3 ubiquitin ligase plays a vital role in the ubiquitin-mediated heat-related protein degradation pathway. Herein, we report that the expression of AtPPRT1, a C3HC4 zinc-finger ubiquitin E3 ligase gene, was induced by heat stress, and the β-glucuronidase (GUS) gene driven by the AtPPRT1 promoter has shown increased activity after basal and acquired thermotolerance. To further explore the function of AtPPRT1 in heat stress response (HSR), we used the atpprt1 mutant and AtPPRT1-overexpressing lines (OE2 and OE10) to expose in heat shock. In this study, the atpprt1 mutant had a lower germination and survival rate than those of Col-0 when suffered from the heat stress, whereas OEs enhanced basal and acquired thermotolerance in Arabidopsis seedlings. When compared to Col-0 and OEs, loss-of-function in AtPPRT1 resulted in lower chlorophyll retention and higher content of reactive oxygen species (ROS) after heat treatment. Moreover, the transcript levels of AtPPRT1 and several heat-related genes (AtZAT12, AtHSP21 and AtHSFA7a) were upregulated to greater extents in OEs and lower extents in atpprt1 compared to Col-0 after heat treated. Hence, we suggest that AtPPRT1 may act as a positive role in regulating the high temperature by mediating the degradation of unknown target proteins.

scholarly journals A Bacterial Type III Effector Targets the Master Regulator of Salicylic Acid Signaling, NPR1, to Subvert Plant Immunity

2017 ◽  
Vol 22 (6) ◽  
pp. 777-788.e7 ◽  
Author(s):  
Huan Chen ◽  
Jian Chen ◽  
Min Li ◽  
Ming Chang ◽  
Kaimei Xu ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Plant Immunity ◽  
Master Regulator ◽  
Type Iii Effector ◽  
Type Iii ◽  
Salicylic Acid Signaling ◽  
Bacterial Type

scholarly journals Proteasomal degradation of JAZ9 by SALT- AND DROUGHT-INDUCED RING FINGER1 during pathogen infection

2021 ◽  
Author(s):  
Vemanna Ramu ◽  
Garima Pal ◽  
Sunhee Oh ◽  
Kirankumar S Mysore
Keyword(s):  
Ubiquitin Ligase ◽  
Disease Susceptibility ◽  
Plant Immunity ◽  
E3 Ubiquitin Ligase ◽  
In Planta ◽  
Yeast Two Hybrid ◽  
Pathogen Infection ◽  
Jaz Proteins ◽  
Molecular Fluorescence ◽  
Two Hybrid

E3 ubiquitin ligase SALT- AND DROUGHT-INDUCED RING FINGER1 (SDIR1) plays a novel role in modulating plant immunity against pathogens. The molecular interactors of SDIR1 during pathogen infection are not known. SDIR1 interacting Jasmonate ZIM-domain (JAZ) proteins were identified through a yeast two-hybrid (Y2H) screen. Full length JAZ9 interacts with SDIR1 only in the presence of coronatine, a bacteria secreted toxin, or jasmonic acid (JA) in Y2H assay. The bi-molecular fluorescence complementation and pull-down assays confirm the in planta interaction of these proteins. JAZ9 proteins, negative regulators of JA-mediated plant defense, were degraded during the pathogen infection by SDIR1 through a proteasomal pathway causing disease susceptibility against hemibiotrophic pathogens.

AtPPRT3, a novel E3 ubiquitin ligase, plays a positive role in ABA signaling

2020 ◽  
Vol 39 (11) ◽  
pp. 1467-1478 ◽  
Author(s):  
Yu Liu ◽  
Lu Peng ◽  
Xuemeng Gao ◽  
Yingying Liu ◽  
Zhibin Liu ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Aba Signaling ◽  
Positive Role

scholarly journals A small secreted protein from Zymoseptoria tritici interacts with a wheat E3 ubiquitin ligase to promote disease

2020 ◽  
Author(s):  
Sujit Jung Karki ◽  
Aisling Reilly ◽  
Binbin Zhou ◽  
Maurizio Mascarello ◽  
James Burke ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Plant Pathogens ◽  
Plant Immunity ◽  
E3 Ubiquitin Ligase ◽  
Bimolecular Fluorescence Complementation ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Virus Induced Gene Silencing ◽  
In Planta ◽  
Zymoseptoria Tritici

Abstract Septoria tritici blotch (STB), caused by the ascomycete fungus Zymoseptoria tritici, is a major threat to wheat production worldwide. The Z. tritici genome encodes many small secreted proteins (ZtSSPs) that are likely to play a key role in the successful colonization of host tissues. However, few of these ZtSSPs have been functionally characterized for their role during infection. In this study, we identified and characterized a small, conserved cysteine-rich secreted effector from Z. tritici which has homologues in other plant pathogens in the Dothideomycetes. ZtSSP2 was expressed throughout Z. tritici infection in wheat, with the highest levels observed early during infection. A yeast two-hybrid assay revealed an interaction between ZtSSP2 and wheat E3 ubiquitin ligase (TaE3UBQ) in yeast, and this was further confirmed in planta using bimolecular fluorescence complementation and co-immunoprecipitation. Down-regulation of this wheat E3 ligase using virus-induced gene silencing increased the susceptibility of wheat to STB. Together, these results suggest that TaE3UBQ is likely to play a role in plant immunity to defend against Z. tritici.

scholarly journals The Majority of the Type III Effector Inventory of Pseudomonas syringae pv. tomato DC3000 Can Suppress Plant Immunity

2009 ◽  
Vol 22 (9) ◽  
pp. 1069-1080 ◽  
Author(s):  
Ming Guo ◽  
Fang Tian ◽  
Yashitola Wamboldt ◽  
James R. Alfano
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Immunity ◽  
In Planta ◽  
Tomato Dc3000 ◽  
Type Iii Effector ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Molecular Pattern ◽  
Effector Triggered Immunity ◽  
Type Iii Protein Secretion

The Pseudomonas syringae type III protein secretion system (T3SS) and the type III effectors it injects into plant cells are required for plant pathogenicity and the ability to elicit a hypersensitive response (HR). The HR is a programmed cell death that is associated with effector-triggered immunity (ETI). A primary function of P. syringae type III effectors appears to be the suppression of ETI and pathogen-associated molecular pattern–triggered immunity (PTI), which is induced by conserved molecules on microorganisms. We reported that seven type III effectors from P. syringae pv. tomato DC3000 were capable of suppressing an HR induced by P. fluorescens(pHIR11) and have now tested 35 DC3000 type III effectors in this assay, finding that the majority of them can suppress the HR induced by HopA1. One newly identified type III effector with particularly strong HR suppression activity was HopS2. We used the pHIR11 derivative pLN1965, which lacks hopA1, in related assays and found that a subset of the type III effectors that suppressed HopA1-induced ETI also suppressed an ETI response induced by AvrRpm1 in Arabidopsis thaliana. A. thaliana plants expressing either HopAO1 or HopF2, two type III effectors that suppressed the HopA1-induced HR, were reduced in the flagellin-induced PTI response as well as PTI induced by other PAMPs and allowed enhanced in planta growth of P. syringae. Collectively, our results suggest that the majority of DC3000 type III effectors can suppress plant immunity. Additionally, the construct pLN1965 will likely be a useful tool in determining whether other type III effectors or effectors from other types of pathogens can suppress either ETI, PTI, or both.

scholarly journals Effector GenexopAEofXanthomonas euvesicatoria85-10 Is Part of an Operon and Encodes an E3 Ubiquitin Ligase

2018 ◽  
Vol 200 (16) ◽  
Author(s):  
Georgy Popov ◽  
Bharat Bhusan Majhi ◽  
Guido Sessa
Keyword(s):  
Ubiquitin Ligase ◽  
Type Iii Secretion ◽  
E3 Ubiquitin Ligase ◽  
E3 Ligase ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Start Codon ◽  
Content Type ◽  
Type Iii ◽  
Xanthomonas Euvesicatoria

ABSTRACTThe type III effector XopAE from theXanthomonas euvesicatoriastrain 85-10 was previously shown to inhibit plant immunity and enhance pathogen-induced disease symptoms. Evolutionary analysis of 60xopAEalleles (AEal) revealed that thexopAElocus is conserved in multipleXanthomonasspecies. The majority ofxopAEalleles (55 out of 60) comprise a single open reading frame (ORF) (xopAE), while in 5 alleles, includingAEal 37of theX. euvesicatoria85-10 strain, a frameshift splits the locus into two ORFs (hpaFand a truncatedxopAE). To test whether the second ORF ofAEal 37(xopAE85-10) is translated, we examined expression of yellow fluorescent protein (YFP) fused downstream to truncated or mutant forms of the locus inXanthomonasbacteria. YFP fluorescence was detected at maximal levels when the reporter was in proximity to an internal ribosome binding site upstream of a rare ATT start codon in thexopAE85-10ORF but was severely reduced when these elements were abolished. In agreement with the notion thatxopAE85-10is a functional gene, its protein product was translocated into plant cells by the type III secretion system, and translocation was dependent on its upstream ORF,hpaF. Homology modeling predicted that XopAE85-10contains an E3 ligase XL box domain at the C terminus, andin vitroassays demonstrated that this domain displays monoubiquitination activity. Remarkably, the XL box was essential for XopAE85-10to inhibit pathogen-associated molecular pattern (PAMP)-induced gene expression inArabidopsisprotoplasts. Together, these results indicate that thexopAE85-10gene resides in a functional operon, which utilizes the alternative start codon ATT and encodes a novel XL box E3 ligase.IMPORTANCEXanthomonasbacteria utilize a type III secretion system to cause disease in many crops. This study provides insights into the evolution, translocation, and biochemical function of the XopAE type III secreted effector, contributing to the understanding ofXanthomonas-host interactions. We establish XopAE as a core effector of sevenXanthomonasspecies and elucidate the evolution of theXanthomonas euvesicatoriaxopAElocus, which contains an operon encoding a truncated effector. Our findings indicate that this operon evolved from the split of a multidomain gene into two ORFs that conserved the original domain function. Analysis ofxopAE85-10translation provides the first evidence for translation initiation from an ATT codon inXanthomonas. Our data demonstrate that XopAE85-10is an XL box E3 ubiquitin ligase and provide insights into the structure and function of this effector family.

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