scholarly journals A Phytophthora sojae CRN effector mediates phosphorylation and degradation of plant aquaporin proteins to suppress host immune signaling

2021 ◽  
Vol 17 (3) ◽  
pp. e1009388
Author(s):  
Gan Ai ◽  
Qingyue Xia ◽  
Tianqiao Song ◽  
Tianli Li ◽  
Hai Zhu ◽  
...  
Keyword(s):  
Higher Plants ◽  
Plant Immunity ◽  
Phytophthora Capsici ◽  
Kinase Domain ◽  
Phytophthora Sojae ◽  
Effector Proteins ◽  
Ros Accumulation ◽  
Oomycete Pathogen ◽  
Cellular Defenses

Phytophthora genomes encode a myriad of Crinkler (CRN) effectors, some of which contain putative kinase domains. Little is known about the host targets of these kinase-domain-containing CRNs and their infection-promoting mechanisms. Here, we report the host target and functional mechanism of a conserved kinase CRN effector named CRN78 in a notorious oomycete pathogen, Phytophthora sojae. CRN78 promotes Phytophthora capsici infection in Nicotiana benthamiana and enhances P. sojae virulence on the host plant Glycine max by inhibiting plant H2O2 accumulation and immunity-related gene expression. Further investigation reveals that CRN78 interacts with PIP2-family aquaporin proteins including NbPIP2;2 from N. benthamiana and GmPIP2-13 from soybean on the plant plasma membrane, and membrane localization is necessary for virulence of CRN78. Next, CRN78 promotes phosphorylation of NbPIP2;2 or GmPIP2-13 using its kinase domain in vivo, leading to their subsequent protein degradation in a 26S-dependent pathway. Our data also demonstrates that NbPIP2;2 acts as a H2O2 transporter to positively regulate plant immunity and reactive oxygen species (ROS) accumulation. Phylogenetic analysis suggests that the phosphorylation sites of PIP2 proteins and the kinase domains of CRN78 homologs are highly conserved among higher plants and oomycete pathogens, respectively. Therefore, this study elucidates a conserved and novel pathway used by effector proteins to inhibit host cellular defenses by targeting and hijacking phosphorylation of plant aquaporin proteins.

scholarly journals A Phytophthora effector recruits a host cytoplasmic transacetylase into nuclear speckles to enhance plant susceptibility

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Haiyang Li ◽  
Haonan Wang ◽  
Maofeng Jing ◽  
Jinyi Zhu ◽  
Baodian Guo ◽  
...  
Keyword(s):  
Root Rot ◽  
Plant Immunity ◽  
Phytophthora Sojae ◽  
Host Immunity ◽  
Effector Proteins ◽  
Nuclear Speckles ◽  
Rxlr Effector ◽  
Plant Susceptibility

Oomycete pathogens secrete host cell-entering effector proteins to manipulate host immunity during infection. We previously showed that PsAvh52, an early-induced RxLR effector secreted from the soybean root rot pathogen, Phytophthora sojae, could suppress plant immunity. Here, we found that PsAvh52 is required for full virulence on soybean and binds to a novel soybean transacetylase, GmTAP1, in vivo and in vitro. PsAvh52 could cause GmTAP1 to relocate into the nucleus where GmTAP1 could acetylate histones H2A and H3 during early infection, thereby promoting susceptibility to P. sojae. In the absence of PsAvh52, GmTAP1 remained confined to the cytoplasm and did not modify plant susceptibility. These results demonstrate that GmTAP1 is a susceptibility factor that is hijacked by PsAvh52 in order to promote epigenetic modifications that enhance the susceptibility of soybean to P. sojae infection.

scholarly journals Downy Mildew effector HaRxL21 interacts with the transcriptional repressor TOPLESS to promote pathogen susceptibility

2020 ◽  
Author(s):  
Sarah Harvey ◽  
Priyanka Kumari ◽  
Dmitry Lapin ◽  
Thomas Griebel ◽  
Richard Hickman ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Transcriptional Repression ◽  
Plant Immunity ◽  
Effector Proteins ◽  
Host Susceptibility ◽  
Close Relative ◽  
C Terminus ◽  
Rxlr Effector ◽  
Oomycete Pathogen ◽  
Hyaloperonospora Arabidopsidis

AbstractHyaloperonospora arabidopsidis (Hpa) is an oomycete pathogen causing Arabidopsis downy mildew. Effector proteins secreted from the pathogen into the plant play key roles in promoting infection by suppressing plant immunity and manipulating the host to the pathogen’s advantage. One class of oomycete effectors share a conserved ‘RxLR’ motif critical for their translocation into the host cell. Here we characterize the interaction between an RxLR effector, HaRxL21 (RxL21), and the Arabidopsis transcriptional co-repressor Topless (TPL). We establish that RxL21 and TPL interact via an EAR motif at the C-terminus of the effector, mimicking the host plant mechanism for recruiting TPL to sites of transcriptional repression. We show that this motif, and hence interaction with TPL, is necessary for the virulence function of the effector. Furthermore, we provide evidence that RxL21 uses the interaction with TPL, and its close relative TPL-related 1, to repress plant immunity and enhance host susceptibility to both biotrophic and necrotrophic pathogens.

scholarly journals The type III effector HopF2Pto targets Arabidopsis RIN4 protein to promote Pseudomonas syringae virulence

2010 ◽  
Vol 107 (5) ◽  
pp. 2349-2354 ◽  
Author(s):  
Mike Wilton ◽  
Rajagopal Subramaniam ◽  
James Elmore ◽  
Corinna Felsensteiner ◽  
Gitta Coaker ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Immunity ◽  
Effector Proteins ◽  
Type Iii ◽  
Pathogen Effector ◽  
Effector Triggered Immunity ◽  
Type Iii Secretion Effector ◽  
Virulence Target

Plant immunity can be induced by two major classes of pathogen-associated molecules. Pathogen- or microbe-associated molecular patterns (PAMPs or MAMPs) are conserved molecular components of microbes that serve as “non-self” features to induce PAMP-triggered immunity (PTI). Pathogen effector proteins used to promote virulence can also be recognized as “non-self” features or induce a “modified-self” state that can induce effector-triggered immunity (ETI). The Arabidopsis protein RIN4 plays an important role in both branches of plant immunity. Three unrelated type III secretion effector (TTSE) proteins from the phytopathogen Pseudomonas syringae, AvrRpm1, AvrRpt2, and AvrB, target RIN4, resulting in ETI that effectively restricts pathogen growth. However, no pathogenic advantage has been demonstrated for RIN4 manipulation by these TTSEs. Here, we show that the TTSE HopF2Pto also targets Arabidopsis RIN4. Transgenic plants conditionally expressing HopF2Pto were compromised for AvrRpt2-induced RIN4 modification and associated ETI. HopF2Pto interfered with AvrRpt2-induced RIN4 modification in vitro but not with AvrRpt2 activation, suggestive of RIN4 targeting by HopF2Pto. In support of this hypothesis, HopF2Pto interacted with RIN4 in vitro and in vivo. Unlike AvrRpm1, AvrRpt2, and AvrB, HopF2Pto did not induce ETI and instead promoted P. syringae growth in Arabidopsis. This virulence activity was not observed in plants genetically lacking RIN4. These data provide evidence that RIN4 is a major virulence target of HopF2Pto and that a pathogenic advantage can be conveyed by TTSEs that target RIN4.

scholarly journals Virulence strategies of an insect herbivore and oomycete plant pathogen converge on host E3 SUMO ligase SIZ1 to suppress plant immunity

2020 ◽  
Author(s):  
S. Liu ◽  
C.J.G. Lenoir ◽  
T.M.M.M. Amaro ◽  
P.A. Rodriguez ◽  
E. Huitema ◽  
...  
Keyword(s):  
Immune Responses ◽  
Plant Immunity ◽  
Phytophthora Capsici ◽  
Negative Regulator ◽  
Herbivorous Insect ◽  
Post Translational Modifications ◽  
Sumo Ligase ◽  
Small Set ◽  
Oomycete Pathogen ◽  
Host Target

AbstractPlant parasites must colonise and reproduce on plants to survive. In most cases, active immune responses, triggered by (conserved) microbe-encoded molecules keep invaders at bay. Post-translational modifications (PTMs) of proteins are vital for contextual regulation and integration of plant immune responses. Pathogens and pests secrete proteins (effectors) to interfere with plant immunity through modification of host target functions and disruption of immune signalling networks. Importantly, molecular virulence strategies of distinct pathogens converge on a small set of regulators with central roles in plant immunity. The extent of convergence between pathogen and herbivorous insect virulence strategies is largely unexplored. Here we report that effectors from the oomycete pathogen, Phytophthora capsici, and the major aphid pest, Myzus persicae target the host immune regulator SIZ1, an E3 SUMO ligase. SIZ1-regulated immunity in Arabidopsis against bacterial pathogens is known to require the resistance protein SNC1, and signalling components PAD4 and EDS1. We show that SIZ1 functions as a negative regulator of plant immunity to aphids and an oomycete pathogen. However, this immune regulation is independent of SNC1, PAD4 and EDS1-signalling pointing to the presence of a novel SIZ1-mediated immune signalling route. Our results suggest convergence of distinct pathogen and pest virulence strategies on an E3 SUMO ligase that negatively regulates plant immunity.

scholarly journals The RXLR Effector PcAvh1 Is Required for Full Virulence of Phytophthora capsici

2019 ◽  
Vol 32 (8) ◽  
pp. 986-1000 ◽  
Author(s):  
Xiao-Ren Chen ◽  
Ye Zhang ◽  
Hai-Yang Li ◽  
Zi-Hui Zhang ◽  
Gui-Lin Sheng ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Plant Immunity ◽  
Phytophthora Capsici ◽  
Ectopic Expression ◽  
Plant Cells ◽  
Effector Proteins ◽  
Bell Pepper ◽  
Broad Host Range ◽  
Virus Induced Gene Silencing ◽  
Rxlr Effector

Plant pathogens employ diverse secreted effector proteins to manipulate host physiology and defense in order to foster diseases. The destructive Phytophthora pathogens encode hundreds of cytoplasmic effectors, which are believed to function inside the plant cells. Many of these cytoplasmic effectors contain the conserved N-terminal RXLR motif. Understanding the virulence function of RXLR effectors will provide important knowledge of Phytophthora pathogenesis. Here, we report the characterization of RXLR effector PcAvh1 from the broad–host range pathogen Phytophthora capsici. Only expressed during infection, PcAvh1 is quickly induced at the early infection stages. CRISPR/Cas9-knockout of PcAvh1 in P. capsici severely impairs virulence while overexpression enhances disease development in Nicotiana benthamiana and bell pepper, demonstrating that PcAvh1 is an essential virulence factor. Ectopic expression of PcAvh1 induces cell death in N. benthamiana, tomato, and bell pepper. Using yeast two-hybrid screening, we found that PcAvh1 interacts with the scaffolding subunit of the protein phosphatase 2A (PP2Aa) in plant cells. Virus-induced gene silencing of PP2Aa in N. benthamiana attenuates resistance to P. capsici and results in dwarfism, suggesting that PP2Aa regulates plant immunity and growth. Collectively, these results suggest that PcAvh1 contributes to P. capsici infection, probably through its interaction with host PP2Aa.

scholarly journals The Phytophthora sojae Avr1d Gene Encodes an RxLR-dEER Effector with Presence and Absence Polymorphisms Among Pathogen Strains

2013 ◽  
Vol 26 (8) ◽  
pp. 958-968 ◽  
Author(s):  
Weixiao Yin ◽  
Suomeng Dong ◽  
Luchong Zhai ◽  
Yachun Lin ◽  
Xiaobo Zheng ◽  
...  
Keyword(s):  
Transient Expression ◽  
Nicotiana Benthamiana ◽  
Plant Immunity ◽  
Phytophthora Sojae ◽  
Transcriptional Analysis ◽  
Mapping Data ◽  
Rxlr Effector ◽  
Effector Triggered Immunity ◽  
Oomycete Pathogen ◽  
Avr Genes

Soybean root and stem rot is caused by the oomycete pathogen Phytophthora sojae. The interaction between P. sojae and soybean fits the “gene-for-gene” hypothesis. Although more than 10 P. sojae avirulence (Avr) effectors have been genetically identified, nearly half of genetically defined avr genes have been cloned. In a previous bioinformatic and global transcriptional analysis, we identified a P. sojae RxLR effector, Avr1d, which was 125 amino acids in length. Mapping data demonstrated that Avr1d presence or absence in the genome was co-segregated with the Avr1d avirulence phenotype in F2 populations. Transient expression of the Avr1d gene using co-bombardment in soybean isogenic lines revealed that this gene triggered a hypersensitive response (HR) in the presence of Rps1d. Sequencing of Avr1d genes in different P. sojae strains revealed two Avr1d alleles. Although polymorphic, the two Avr1d alleles could trigger Rps1d-mediated HR. P. sojae strains carrying either of the alleles were avirulent on Rps1d soybean lines. Avr1d was upregulated during the germinating cyst and early infection stages. Furthermore, transient expression of Avr1d in Nicotiana benthamiana suppressed BAX-induced cell death and enhanced P. capsici infection. Avr1d also suppressed effector-triggered immunity induction by associating with Avr1b and Rps1b, suggestive of a role in suppressing plant immunity.

scholarly journals A Valsa mali Effector Protein 1 Targets Apple (Malus domestica) Pathogenesis-Related 10 Protein to Promote Virulence

2021 ◽  
Vol 12 ◽  
Author(s):  
Weidong Wang ◽  
Jiajun Nie ◽  
Luqiong Lv ◽  
Wan Gong ◽  
Shuaile Wang ◽  
...  
Keyword(s):  
Malus Domestica ◽  
Plant Immunity ◽  
Effector Proteins ◽  
Parasitic Fungus ◽  
Effector Protein ◽  
Positive Role ◽  
Host Immune Responses ◽  
Pathogenesis Related ◽  
Valsa Mali

To successfully colonize the plants, the pathogenic microbes secrete a mass of effector proteins which manipulate host immunity. Apple valsa canker is a destructive disease caused by the weakly parasitic fungus Valsa mali. A previous study indicated that the V. mali effector protein 1 (VmEP1) is an essential virulence factor. However, the pathogenic mechanism of VmEP1 in V. mali remains poorly understood. In this study, we found that the apple (Malus domestica) pathogenesis-related 10 proteins (MdPR10) are the virulence target of VmEP1 using a yeast two-hybrid screening. By bimolecular fluorescence (BiFC) and coimmunoprecipitation (Co-IP), we confirmed that the VmEP1 interacts with MdPR10 in vivo. Silencing of MdPR10 notably enhanced the V. mali infection, and overexpression of MdPR10 markedly reduced its infection, which corroborates its positive role in plant immunity against V. mali. Furthermore, we showed that the co-expression of VmEP1 with MdPR10 compromised the MdPR10-mediated resistance to V. mali. Taken together, our results revealed a mechanism by which a V. mali effector protein suppresses the host immune responses by interfering with the MdPR10-mediated resistance to V. mali during the infection.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

scholarly journals Ubiquitylome Analysis Reveals a Central Role for the Ubiquitin-Proteasome System in Plant Innate Immunity

2021 ◽  
Author(s):  
Xiyu Ma ◽  
Chao Zhang ◽  
Do Young Kim ◽  
Yanyan Huang ◽  
Elizabeth Chatt ◽  
...  
Keyword(s):  
Plant Immunity ◽  
High Sensitivity ◽  
Ubiquitin Proteasome System ◽  
Immune Recognition ◽  
Atpase Subunit ◽  
Ample Evidence ◽  
Network Analyses ◽  
Affinity Enrichment ◽  
Regulatory Loop

Abstract Protein ubiquitylation profoundly expands proteome functionality and diversifies cellular signaling processes, with recent studies providing ample evidence for its importance to plant immunity. To gain a proteome-wide appreciation of ubiquitylome dynamics during immune recognition, we employed a two-step affinity enrichment protocol based on a 6His-tagged ubiquitin (Ub) variant coupled with high sensitivity mass spectrometry to identify Arabidopsis proteins rapidly ubiquitylated upon plant perception of the microbe-associated molecular pattern (MAMP) peptide flg22. The catalog from 2-week-old seedlings treated for 30 minutes with flg22 contained 690 conjugates, 64 Ub footprints, and all seven types of Ub linkages, and included previously uncharacterized conjugates of immune components. In vivo ubiquitylation assays confirmed modification of several candidates upon immune elicitation, and revealed distinct modification patterns and dynamics for key immune components, including poly- and monoubiquitylation, as well as induced or reduced levels of ubiquitylation. Gene ontology and network analyses of the collection also uncovered rapid modification of the Ub-proteasome system itself, suggesting a critical auto-regulatory loop necessary for an effective MAMP-triggered immune response and subsequent disease resistance. Included targets were UBIQUITIN-CONJUGATING ENZYME 13 (UBC13) and proteasome component REGULATORY PARTICLE NON-ATPASE SUBUNIT 8b (RPN8b), whose subsequent biochemical and genetic analyses implied negative roles in immune elicitation. Collectively, our proteomic analyses further strengthened the connection between ubiquitylation and flg22-based immune signaling, identified components and pathways regulating plant immunity, and increased the database of ubiquitylated substrates in plants.

Sign in / Sign up

Export Citation Format

Share Document