scholarly journals Multiple Candidate Effectors from the Oomycete Pathogen Hyaloperonospora arabidopsidis Suppress Host Plant Immunity

2011 ◽  
Vol 7 (11) ◽  
pp. e1002348 ◽  
Author(s):  
Georgina Fabro ◽  
Jens Steinbrenner ◽  
Mary Coates ◽  
Naveed Ishaque ◽  
Laura Baxter ◽  
...  
Keyword(s):  
Host Plant ◽  
Plant Immunity ◽  
Oomycete Pathogen ◽  
Hyaloperonospora Arabidopsidis

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 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.

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

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.

scholarly journals Modulation of host plant immunity by Tobamovirus proteins

2016 ◽  
pp. mcw216 ◽  
Author(s):  
G. Conti ◽  
M. C. Rodriguez ◽  
A. L. Venturuzzi ◽  
S. Asurmendi
Keyword(s):  
Host Plant ◽  
Plant Immunity

scholarly journals Production of dsRNA Sequences in the Host Plant Is Not Sufficient to Initiate Gene Silencing in the Colonizing Oomycete Pathogen Phytophthora parasitica

PLoS ONE ◽  
2011 ◽  
Vol 6 (11) ◽  
pp. e28114 ◽  
Author(s):  
Meixiang Zhang ◽  
Qinhu Wang ◽  
Ke Xu ◽  
Yuling Meng ◽  
Junli Quan ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Host Plant ◽  
Phytophthora Parasitica ◽  
Oomycete Pathogen

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.

OBSERVATIONS ON HOST PLANT INDUCED BEHAVIOR OF SCALE INSECTS AND THEIR ENDOPARASITES

1970 ◽  
Vol 102 (8) ◽  
pp. 913-926 ◽  
Author(s):  
S. E. Flanders
Keyword(s):  
Host Plant ◽  
Physiological Response ◽  
Host Plants ◽  
Plant Immunity ◽  
Scale Insects ◽  
Great Abundance ◽  
Edaphic Conditions ◽  
Saissetia Oleae ◽  
Induced Immunity ◽  
Host Regulation

AbstractDifferences in the behavior of scale insects induced by their host plants has been observed, principally, in uniparental, bisexual, univoltine species. Behavior in endoparasites of such species also may be thus modified. The phenomena involved, reproductivity, sexuality, voltinism and, with the parasites, host-regulation, are related to the environmentally induced immunity of the host plant to its indigenous scale insects.This immunity, when not a regional phenomenon, is necessarily sporadic. When operative, it may he as complete as generic-immunity. Periodic host plant non-susceptibility is considered to he a physiological response to meteorological and edaphic conditions, a response usually rendering the plant temporarily unsuitable for coccid development. The interpolation of immune periods in the life of a coccid’s normal host plant necessarily disrupts the continuity of the host-regulative action of the coccid’s parasites. Host plant pheno-immunity was first clearly manifested in regions where Lecanium corni Bouché, L. tiliae (Linnaeus), and Saissetia oleae (Bernard) free of their regulative parasites, reproduced in great abundance. In regions to which these coccids are indigenous the limitation of their outbreaks to artificial monocultures attested to the obscure nature of host plant pheno-immunity. The cessation of host plant immunity to coccids, the subsequent heavy reinfestation, and then the parasitic elimination of the outbreak attested to the host-regulative power of parasitization.

Two BTB proteins function redundantly as negative regulators of defense against pathogens in Arabidopsis

Botany ◽  
2010 ◽  
Vol 88 (11) ◽  
pp. 953-960 ◽  
Author(s):  
Na Qu ◽  
Wenjian Gan ◽  
Dongling Bi ◽  
Shitou Xia ◽  
Xin Li ◽  
...  
Keyword(s):  
Double Mutant ◽  
Pathogen Resistance ◽  
Negative Regulators ◽  
Double Knockout ◽  
Protein Protein Interaction ◽  
Btb Domain ◽  
Enhanced Sensitivity ◽  
Oomycete Pathogen ◽  
Hyaloperonospora Arabidopsidis ◽  
Two Hybrid

The BTB domain is a protein–protein interaction motif found throughout eukaryotes. Here we report the identification of two closely related BTB domain-containing proteins, POZ/BTB CONTAINING-PROTEIN 1 (POB1) and POB2, as negative regulators of defense against pathogens. In yeast two-hybrid assays, POB1 and POB2 dimerize through their BTB domains. The pob1–1 pob2–1 double mutant plants exhibited enhanced resistance against the fungal pathogen Botrytis cinerea and the oomycete pathogen Hyaloperonospora arabidopsidis Noco2. Double knockout, but not single mutants of pob1–1 and pob2–1, displayed enhanced sensitivity to growth inhibition by jasmonic acid (JA). In addition, expression of the JA-responsive defensin gene PDF1.2 is enhanced in the pob1–1 pob2–1 double mutant. Our data suggest that POB1 and POB2 function redundantly as negative regulators of JA-mediated pathogen resistance responses.

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