scholarly journals BAX INHIBITOR-1 Is Required for Full Susceptibility of Barley to Powdery Mildew

2010 ◽  
Vol 23 (9) ◽  
pp. 1217-1227 ◽  
Author(s):  
Ruth Eichmann ◽  
Melanie Bischof ◽  
Corina Weis ◽  
Jane Shaw ◽  
Christophe Lacomme ◽  
...  
Keyword(s):  
Cell Death ◽  
Powdery Mildew ◽  
Gene Silencing ◽  
Defense Responses ◽  
Negative Control ◽  
Cellular Level ◽  
Virus Induced Gene Silencing ◽  
Powdery Mildew Fungus ◽  
Basal Resistance ◽  
Enhanced Resistance

BAX INHIBITOR-1 (BI-1) is one of the few proteins known to have cross-kingdom conserved functions in negative control of programmed cell death. Additionally, barley BI-1 (HvBI-1) suppresses defense responses and basal resistance to the powdery mildew fungus Blumeria graminis f. sp. hordei and enhances resistance to cell death–provoking fungi when overexpressed in barley. Downregulation of HvBI-1 by transient-induced gene silencing or virus-induced gene silencing limited susceptibility to B. graminis f. sp. hordei, suggesting that HvBI-1 is a susceptibility factor toward powdery mildew. Transient silencing of BI-1 did not limit supersusceptibility induced by overexpression of MLO. Transgenic barley plants harboring an HvBI-1 RNA interference (RNAi) construct displayed lower levels of HvBI-1 transcripts and were less susceptible to powdery mildew than wild-type plants. At the cellular level, HvBI-1 RNAi plants had enhanced resistance to penetration by B. graminis f. sp. hordei. These data support a function of BI-1 in modulating cell-wall-associated defense and in establishing full compatibility of B. graminis f. sp. hordei with barley.

scholarly journals The ELR-SOBIR1 Complex Functions as a Two-Component Receptor-Like Kinase to Mount Defense Against Phytophthora infestans

2018 ◽  
Vol 31 (8) ◽  
pp. 795-802 ◽  
Author(s):  
Emmanouil Domazakis ◽  
Doret Wouters ◽  
Richard G. F. Visser ◽  
Sophien Kamoun ◽  
Matthieu H. A. J. Joosten ◽  
...  
Keyword(s):  
Cell Death ◽  
Phytophthora Infestans ◽  
Defense Responses ◽  
Virus Induced Gene Silencing ◽  
In Planta ◽  
Basal Resistance ◽  
Downstream Signaling ◽  
Receptor Like Kinase ◽  
Signaling Domain ◽  
Signaling Activation

The ELICITIN RESPONSE protein (ELR) from Solanum microdontum can recognize INF1 elicitin of Phytophthora infestans and trigger defense responses. ELR is a receptor-like protein (RLP) that lacks a cytoplasmic signaling domain and is anticipated to require interaction with a signaling-competent receptor-like kinase. SUPPRESSOR OF BIR1-1 (SOBIR1) has been proposed as a general interactor for RLPs involved in immunity and, as such, is a potential interactor for ELR. Here, we investigate whether SOBIR1 is required for response to INF1 and resistance to P. infestans and whether it associates with ELR. Our results show that virus-induced gene silencing of SOBIR1 in Nicotiana benthamiana leads to loss of INF1-triggered cell death and increased susceptibility to P. infestans. Using genetic complementation, we found that the kinase activity of SOBIR1 is required for INF1-triggered cell death. Coimmunoprecipitation experiments showed that ELR constitutively associates with potato SOBIR1 in planta, forming a bipartite receptor complex. Upon INF1 elicitation, this ELR-SOBIR1 complex recruits SERK3 (SOMATIC EMBRYOGENESIS RECEPTOR KINASE 3) leading to downstream signaling activation. Overall, our study shows that SOBIR1 is required for basal resistance to P. infestans and for INF1-triggered cell death and functions as an adaptor kinase for ELR.

scholarly journals The Arabidopsis Gain-of-Function Mutant ssi4 Requires RAR1 and SGT1b Differentially for Defense Activation and Morphological Alterations

2008 ◽  
Vol 21 (1) ◽  
pp. 40-49 ◽  
Author(s):  
Fasong Zhou ◽  
Stephen Mosher ◽  
Miaoying Tian ◽  
Giovanna Sassi ◽  
Jane Parker ◽  
...  
Keyword(s):  
Cell Death ◽  
Defense Responses ◽  
R Gene ◽  
Lesion Formation ◽  
Triple Mutant ◽  
Gain Of Function ◽  
Pathogen Infection ◽  
Basal Resistance ◽  
Morphological Alterations ◽  
Induced Disease Resistance

A gain-of-function mutation in resistance (R) gene SSI4 causes constitutive activation of defense responses, spontaneous necrotic lesion formation, enhanced resistance against virulent pathogens, and a severe dwarf phenotype. Genetic analysis revealed that ssi4-induced H2O2 accumulation and spontaneous cell death require RAR1, whereas ssi4-mediated stunting is dependent on SGT1b. By contrast, both RAR1 and SGT1b are required in a genetically additive manner for ssi4-induced disease resistance, SA accumulation, and lesion formation after pathogen infection. These data point to cooperative yet distinct functions of RAR1 and SGT1b in responses conditioned by a deregulated nucleotide-binding leucine-rich repeat protein. We also found that RAR1 and SGT1b together contribute to basal resistance because an ssi4 rar1 sgt1b triple mutant exhibited enhanced susceptibility to virulent pathogen infection compared with wild-type SSI4 plants. All ssi4-induced phenotypes were suppressed when plants were grown at 22°C under high relative humidity. However, low temperature (16°C) triggered ssi4-mediated cell death via an RAR1-dependent pathway even in the presence of high humidity. Thus, multiple environmental factors impact on ssi4 signaling, as has been observed for other constitutive defense mutants and R gene-triggered pathways.

Virus-induced gene silencing of SlPKY1 attenuates defense responses against gray leaf spot in tomato

2020 ◽  
Vol 264 ◽  
pp. 109149
Author(s):  
Yaoguang Sun ◽  
Te Wang ◽  
Mingyue Liu ◽  
Zhongxin Nie ◽  
Huanhuan Yang ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Leaf Spot ◽  
Defense Responses ◽  
Gray Leaf Spot ◽  
Virus Induced Gene Silencing

scholarly journals A Verticillium dahliae Extracellular Cutinase Modulates Plant Immune Responses

2018 ◽  
Vol 31 (2) ◽  
pp. 260-273 ◽  
Author(s):  
Yue-Jing Gui ◽  
Wen-Qi Zhang ◽  
Dan-Dan Zhang ◽  
Lei Zhou ◽  
Dylan P. G. Short ◽  
...  
Keyword(s):  
Cell Death ◽  
Plant Defense ◽  
Verticillium Dahliae ◽  
Fungal Pathogens ◽  
Sequence Divergence ◽  
Defense Responses ◽  
Carbohydrate Binding ◽  
Dependent Manner ◽  
Virus Induced Gene Silencing ◽  
Plant Defense Responses

Cutinases have been implicated as important enzymes during the process of fungal infection of aerial plant organs. The function of cutinases in the disease cycle of fungal pathogens that invade plants through the roots has been less studied. Here, functional analysis of 13 cutinase (carbohydrate esterase family 5 domain–containing) genes (VdCUTs) in the highly virulent vascular wilt pathogen Verticillium dahliae Vd991 was performed. Significant sequence divergence in cutinase family members was observed in the genome of V. dahliae Vd991. Functional analyses demonstrated that only VdCUT11, as purified protein, induced cell death and triggered defense responses in Nicotiana benthamiana, cotton, and tomato plants. Virus-induced gene silencing showed that VdCUT11 induces plant defense responses in Nicotiana benthamania in a BAK1 and SOBIR-dependent manner. Furthermore, coinfiltration assays revealed that the carbohydrate-binding module family 1 protein (VdCBM1) suppressed VdCUT11-induced cell death and other defense responses in N. benthamiana. Targeted deletion of VdCUT11 in V. dahliae significantly compromised virulence on cotton plants. The cutinase VdCUT11 is an important secreted enzyme and virulence factor that elicits plant defense responses in the absence of VdCBM1.

scholarly journals A Compromised Mlo Pathway Affects the Response of Barley to the Necrotrophic Fungus Bipolaris sorokiniana (Teleomorph: Cochliobolus sativus) and Its Toxins

2001 ◽  
Vol 91 (2) ◽  
pp. 127-133 ◽  
Author(s):  
Jagdish Kumar ◽  
Ralph Hückelhoven ◽  
Ulrich Beckhove ◽  
Subrahmaniam Nagarajan ◽  
Karl-Heinz Kogel
Keyword(s):  
Cell Death ◽  
Cell Wall ◽  
Powdery Mildew ◽  
Bipolaris Sorokiniana ◽  
Spot Blotch ◽  
Cochliobolus Sativus ◽  
Fungal Culture ◽  
Wild Type ◽  
Powdery Mildew Fungus ◽  
Resistance Traits

In search of new durable disease resistance traits in barley to control leaf spot blotch disease caused by the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus), we developed macroscopic and microscopic scales to judge spot blotch disease development on barley. Infection of barley was associated with cell wall penetration and accumulation of hydrogen peroxide. The latter appeared to take place in cell wall swellings under fungal penetration attempts as well as during cell death provoked by the necrotrophic pathogen. Additionally, we tested the influence of a compromised Mlo pathway that confers broad resistance against powdery mildew fungus (Blumeria graminis f. sp. hordei). Powdery mildew-resistant genotypes with mutations at the Mlo locus (mlo genotypes) showed a higher sensitivity to infiltration of toxic culture filtrate of Bipolaris sorokiniana as compared with wild-type barley. Mutants defective in Ror, a gene required for mlo-specified powdery mildew resistance, were also more sensitive to Bipolaris sorokiniana toxins than wild-type barley but showed less symptoms than mlo5 parents. Fungal culture filtrates induced an H2O2 burst in all mutants, whereas wild-type (Mlo) barley was less sensitive. The results support the hypothesis that the barley Mlo gene product functions as a suppresser of cell death. Therefore, a compromised Mlo pathway is effective for control of biotrophic powdery mildew fungus but not for necrotrophic Bipolaris sorokiniana. We discuss the problem of finding resistance traits that are effective against both biotrophic and necrotrophic pathogens with emphasis on the role of the anti-oxidative system of plant cells.

scholarly journals Characterizing virus-induced gene silencing at the cellular level with in situ multimodal imaging

Plant Methods ◽  
2018 ◽  
Vol 14 (1) ◽  
Author(s):  
Sadie J. Burkhow ◽  
Nicole M. Stephens ◽  
Yu Mei ◽  
Maria Emilia Dueñas ◽  
Daniel J. Freppon ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Multimodal Imaging ◽  
Cellular Level ◽  
Virus Induced Gene Silencing

scholarly journals The partial duplication of an E3-ligase gene in Triticeae species mediates resistance to powdery mildew fungi

2017 ◽  
Author(s):  
Jeyaraman Rajaraman ◽  
Dimitar Douchkov ◽  
Stefanie Lück ◽  
Götz Hensel ◽  
Daniela Nowara ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
E3 Ligase ◽  
Defense Responses ◽  
Duplication Event ◽  
Stable Gene ◽  
Cellular Functions ◽  
Powdery Mildew Fungus ◽  
Crop Species ◽  
Powdery Mildew Fungi ◽  
Plant Pathogen Interactions

ABSTRACTIn plant-pathogen interactions, components of the plant ubiquitination machinery are preferred targets of pathogen-encoded effectors suppressing defense responses or co-opting host cellular functions for accommodation. Here, we employed transient and stable gene silencing-and over-expression systems in Hordeum vulgare (barley) to study the function of HvARM1 (for H. vulgare Armadillo 1), a partial gene duplicate of the U-box/armadillo-repeat E3 ligase HvPUB15 (for H. vulgare Plant U-Box 15). The partial ARM1 gene was derived from an ancient gene-duplication event in a common ancestor of the Triticeae tribe of grasses comprising the major crop species H. vulgare, Triticum aestivum and Secale cereale. The barley gene HvARM1 contributed to quantitative host as well as nonhost resistance to the biotrophic powdery mildew fungus Blumeria graminis, and allelic variants were found to be associated with powdery mildew-disease severity. Both HvPUB15 and HvARM1 proteins interacted in yeast and plant cells with the susceptibility-related, plastid-localized barley homologs of THF1 (for Thylakoid formation 1) and of ClpS1 (for Clp-protease adaptor S1) of Arabidopsis thaliana. The results suggest a neo-functionalization HvARM1 to increase resistance against powdery mildew and provide a link to plastid function in susceptibility to biotrophic pathogen attack.

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