scholarly journals A Barley Powdery Mildew Fungus Non-Autonomous Retrotransposon Encodes a Peptide that Supports Penetration Success on Barley

2018 ◽  
Author(s):  
Mathias Nottensteiner ◽  
Bernd Zechmann ◽  
Christopher McCollum ◽  
Ralph Hückelhoven
Keyword(s):  
Powdery Mildew ◽  
Host Cell ◽  
Plant Immunity ◽  
Epidermal Cells ◽  
Bimolecular Fluorescence Complementation ◽  
Transcriptional Gene Silencing ◽  
In Planta ◽  
Powdery Mildew Fungus ◽  
Microtubule Organization ◽  
Rop Gtpase

ABSTRACTPlant immunity is overcome by pathogens by the means of secreted effectors. Host effector targets might be proteins acting in pathogen defense or serve demands of the pathogen. The barley ROP GTPase HvRACB is involved in entry of the powdery mildew fungusBlumeria graminisf.sp.hordei (Bgh)into barley epidermal cells. We found that HvRACB interacts with theROP-interactive peptide 1 (ROPIP1) that is encoded on the active non-long terminal repeat retroelement Eg-R1 ofBgh. Over-expression of ROPIP1 in barley epidermal cells and host-induced post-transcriptional gene silencing (HIGS) ofROPIP1suggested that ROPIP1 is involved in virulence ofBgh. Bimolecular fluorescence complementation and co-localization supported that ROPIP1 can interact with activated HvRACB in planta. We show that ROPIP1 is expressed byBghon barley and translocated into the cytoplasm of infected barley cells. ROPIP1 is recruited to microtubules upon co-expression of MICROTUBULE ASSOCIATED ROP GTPase ACTIVATING PROTEIN (HvMAGAP1) and can destabilize cortical microtubules.BghROPIP might target HvRACB and manipulate host cell microtubule organization for facilitated host cell entry. Data suggest a possible neo-functionalization of retroelement-derived transcripts for the evolution of a pathogen virulence effector.

scholarly journals A Barley ROP GTPase ACTIVATING PROTEIN Associates with Microtubules and Regulates Entry of the Barley Powdery Mildew Fungus into Leaf Epidermal Cells

2011 ◽  
Vol 23 (6) ◽  
pp. 2422-2439 ◽  
Author(s):  
Caroline Hoefle ◽  
Christina Huesmann ◽  
Holger Schultheiss ◽  
Frederik Börnke ◽  
Götz Hensel ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Epidermal Cells ◽  
Gtpase Activating Protein ◽  
Powdery Mildew Fungus ◽  
Barley Powdery Mildew ◽  
Rop Gtpase

scholarly journals ROP INTERACTIVE PARTNER b interacts with RACB and supports fungal penetration into barley epidermal cells

2019 ◽  
Author(s):  
Christopher McCollum ◽  
Stefan Engelhardt ◽  
Lukas Weiss ◽  
Ralph Hückelhoven
Keyword(s):  
Plasma Membrane ◽  
Powdery Mildew ◽  
Coiled Coil ◽  
Cell Polarization ◽  
Epidermal Cells ◽  
In Planta ◽  
Powdery Mildew Fungus ◽  
Susceptibility Factor ◽  
Polar Cell ◽  
Barley Powdery Mildew

AbstractRHO of Plants (ROP) G-proteins are key components of cell polarization processes in plant development. The barley (Hordeum vulgare) ROP protein RACB, is a susceptibility factor in the interaction of barley with the barley powdery mildew fungus Blumeria graminis f.sp. hordei (Bgh). RACB also drives polar cell development, and this function might be coopted during formation of fungal haustoria in barley epidermal cells. In order to understand RACB signaling during the interaction of barley with Bgh, we searched for potential downstream interactors of RACB. Here, we show that ROP INTERACTIVE PARTNER b (RIPb, synonym: INTERACTOR OF CONSTITUTIVE ACTIVE ROP b; ICRb) directly interacts with RACB in yeast and in planta. Over-expression of RIPb supports susceptibility of barley to Bgh. RIPb further interacts with itself at microtubules. However, the interaction with activated RACB takes place at the plasma membrane. Both, RIPb and RACB are recruited to the site of fungal attack around the neck of developing haustoria suggesting locally enhanced ROP activity. We further assigned different functions to different domains of the RIPb protein. The N-terminal coiled-coil CC1 domain is required for microtubule localization, while the C-terminal coiled-coil CC2 domain is sufficient to interact with RACB and to fulfill a function in susceptibility at the plasma membrane. Hence, RIPb appears to be localized at microtubules and is then recruited by activated RACB for a function at the plasma membrane during formation of the haustorial complex.One Sentence summaryRIPb acts downstream of the powdery mildew susceptibility factor RACB of barley and influences susceptibility

The ultrastructure of M1-a-mediated resistance to powdery mildew infection in barley

1975 ◽  
Vol 53 (22) ◽  
pp. 2589-2597 ◽  
Author(s):  
H. H. Edwards
Keyword(s):  
Powdery Mildew ◽  
Host Cell ◽  
Electron Density ◽  
Epidermal Cells ◽  
Dense Material ◽  
Ultrastructural Changes ◽  
Electron Dense Material ◽  
Host Cytoplasm ◽  
Powdery Mildew Infection ◽  
Cell Protoplast

M1-a-mediated resistance in barley to invasion by the CR3 race of Erysiphe graminis f. sp. hordei does not occur in every host cell with the same speed and severity. In some cells ultrastructural changes within the host cell as a result of resistance will occur within 24 h after inoculation, whereas in other cells these changes may take up to 72 h. In some cells the ultrastructural changes are so drastic that they give the appearance of a hypersensitive death of the host cell, whereas in other cells the changes are very slight. In any case, at the end of these changes the fungus ceases growth. The ultrastructural changes occur in penetrated host epidermal cells as well as non-infected adjacent epidermal and mesophyll cells.The following ultrastructural changes have been observed: (1) an electron-dense material which occurs either free in the vacuole or adhering to the tonoplast (the material is granular or in large clumps); (2) an increased electron density of the host cytoplasm and nucleus; (3) a breakdown of the tonoplast so that the cytoplasmic constituents become dispersed throughout the cell lumen; and (4) the deposition of papillar-like material in areas other than the penetration site. The first three changes take place within the host cell protoplasts and are directly attributable to the gene M1-a. These changes are typical of stress or incompatibility responses and thus M1-a appears to trigger a generalized incompatibility response in the presence of race CR3. The papillar-like material occurs outside the host cell protoplast in the same manner as the papilla and probably is not directly attributable to M1-a.

A putative effector of the rubber-tree powdery mildew fungus has elicitor activity that can trigger plant immunity

Planta ◽  
2022 ◽  
Vol 255 (2) ◽  
Author(s):  
Xiao Li ◽  
Mengyao Liu ◽  
Yuhan Liu ◽  
Wenyuan Zhao ◽  
Sipeng Li ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Plant Immunity ◽  
Rubber Tree ◽  
Powdery Mildew Fungus

scholarly journals A Small GTP-Binding Host Protein Is Required for Entry of Powdery Mildew Fungus into Epidermal Cells of Barley

2002 ◽  
Vol 128 (4) ◽  
pp. 1447-1454 ◽  
Author(s):  
Holger Schultheiss ◽  
Cornelia Dechert ◽  
Karl-Heinz Kogel ◽  
Ralph Hückelhoven
Keyword(s):  
Powdery Mildew ◽  
Epidermal Cells ◽  
Host Protein ◽  
Powdery Mildew Fungus ◽  
Gtp Binding

scholarly journals Differential Gene Expression in Individual Papilla-Resistant and Powdery Mildew-Infected Barley Epidermal Cells

2004 ◽  
Vol 17 (7) ◽  
pp. 729-738 ◽  
Author(s):  
Torben Gjetting ◽  
Timothy L. W. Carver ◽  
Leif Skøt ◽  
Michael F. Lyngkjær
Keyword(s):  
Gene Expression ◽  
Powdery Mildew ◽  
Single Cell ◽  
Pcr Amplification ◽  
Epidermal Cells ◽  
Powdery Mildew Fungus ◽  
Pathogenesis Related Protein ◽  
Infected Cells ◽  
Transcript Profiles ◽  
Microarray Expression

Resistance and susceptibility in barley to the powdery mildew fungus (Blumeria graminis f. sp. hordei) is determined at the single-cell level. Even in genetically compatible interactions, attacked plant epidermal cells defend themselves against attempted fungal penetration by localized responses leading to papilla deposition and reinforcement of their cell wall. This conveys a race-nonspecific form of resistance. However, this defense is not complete, and a proportion of penetration attempts succeed in infection. The resultant mixture of infected and uninfected leaf cells makes it impossible to relate powdery mildew-induced gene expression in whole leaves or even dissected epidermal tissues to resistance or susceptibility. A method for generating transcript profiles from individual barley epidermal cells was established and proven useful for analyzing resistant and successfully infected cells separately. Contents of single epidermal cells (resistant, infected, and unattacked controls) were collected, and after cDNA synthesis and PCR amplification, the resulting sample was hybridized to dot-blots spotted with genes, including some previously reported to be induced upon pathogen attack. Transcripts of several genes, (e.g., PR1a, encoding a pathogenesis related protein, and GLP4, encoding a germin-like protein) accumulated specifically in resistant cells, while GRP94, encoding a molecular chaperone, accumulated in infected cells. Thus, the single-cell method allows discrimination of transcript profiles from resistant and infected cells. The method will be useful for microarray expression profiling for simultaneous analysis of many genes.

Defense reactions of barley cultivars to an inappropriate forma specialis of the powdery mildew fungus of gramineous plants

1984 ◽  
Vol 62 (10) ◽  
pp. 2114-2117 ◽  
Author(s):  
Y. Tosa ◽  
J. Shishiyama
Keyword(s):  
Powdery Mildew ◽  
Colony Growth ◽  
Epidermal Cells ◽  
Colony Development ◽  
Powdery Mildew Fungus ◽  
Barley Cultivars ◽  
Cellular Defense ◽  
Defense Reactions ◽  
Forma Specialis ◽  
Fluorescent Cells

Cellular defense reactions in five barley cultivars against Erysiphe graminis f. sp. tritici were examined in the course of primary and secondary penetrations. In cv. Kairyobozu-mugi, 35% of infection attempts were stopped at fluorescent papillae, and the others (65%) induced fluorescing of epidermal cells, resulting in the failure of the formation of primary haustoria. In the other cultivars ('H.E.S.4', 'Russian No. 12', 'Goseshikoku', and 'Turkey 290') the penetration failures associated with fluorescent papillae reached 50–75%, but the infection attempts that induced the fluorescing of epidermal cells were fewer than 20%. Consequently 10–30% of the germlings that attempted penetration successfully formed normal primary haustoria 48 h after inoculation. In cv. Goseshikoku, cv. Russian No. 12, and cv. H.E.S.4, 50–75% of the epidermal cells that contained the primary haustoria were fluorescent 7 days after inoculation, and colony growth was severely restricted. In cv. Turkey 290 such fluorescent cells scarcely occurred and colonies developed comparatively well. On this cultivar conidia were produced 5–6 days after inoculation, but only in small quantities. This restriction of colony development was mainly attributable to the inhibition of the formation of secondary haustoria by fluorescent papillae. These results indicate that there are differences among barley cultivars in cellular defense reactions against the wheat powdery mildew fungus and suggest that the formation of papillae during the course of primary penetration is not necessarily an essential factor in the resistance of barley to this inappropriate forma specialis.

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 Barley ROP Binding Kinase1 Is Involved in Microtubule Organization and in Basal Penetration Resistance to the Barley Powdery Mildew Fungus

2012 ◽  
Vol 159 (1) ◽  
pp. 311-320 ◽  
Author(s):  
Christina Huesmann ◽  
Tina Reiner ◽  
Caroline Hoefle ◽  
Jutta Preuss ◽  
Manuela E. Jurca ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Penetration Resistance ◽  
Powdery Mildew Fungus ◽  
Microtubule Organization ◽  
Barley Powdery Mildew

scholarly journals Tissue-Specific Superoxide Generation at Interaction Sites in Resistant and Susceptible Near-Isogenic Barley Lines Attacked by the Powdery Mildew Fungus (Erysiphe graminis f. sp. hordei)

1998 ◽  
Vol 11 (4) ◽  
pp. 292-300 ◽  
Author(s):  
Ralph Hückelhoven ◽  
Karl-Heinz Kogel
Keyword(s):  
Cell Death ◽  
Powdery Mildew ◽  
Mesophyll Cell ◽  
Epidermal Cells ◽  
Erysiphe Graminis ◽  
Time Range ◽  
Powdery Mildew Fungus ◽  
Hypersensitive Cell Death ◽  
Interaction Sites ◽  
Nbt Reduction

The pathogenesis-related, azide-insensitive generation of superoxide anions (O2 -) was comparatively analyzed in near-isogenic barley (Hordeum vulgare cv. Pallas) lines carrying the powdery mildew (Erysiphe graminis f. sp. hordei) resistance genes Mla12, Mlg, and mlo5, respectively, by the microscopic detection of nitroblue tetra-zolium (NBT) reduction to dark blue formazan dyes. These genes govern fungal arrest at different stages of the interaction: (i) at the penetration stage within cell wall appositions (papillae) leaving the attacked cell alive (mlo); (ii) within papillae of cells that subsequently undergo a hypersensitive cell death (HR) (Mlg); or (iii) after penetration by a subsequent HR (Mla12). The susceptible parent line Pallas showed a transient O2 - generation in penetrated epidermal cells at 18 h after inoculation (hai), whereas epidermal cells of the resistant BCPMla12 produced O2 - over a longer time range (by 18 to 36 hai) preceding cell death. No oxidative burst was detected in association with penetration resistance due to effective papillae (BCPMlg and BCPmlo5) although Mlg specified an HR subsequent to fungal arrest. Hence, O2 - generation in attacked epidermal cells was a result of fungal penetration of the host cell walls and subsequent contact with the host plasma membrane, and not a requirement for HR elicitation. O2 - generation in the mesophyll tissue beneath attacked cells was associated with the response mediated by the genes Mla12 and Mlg. However, only BCPMla12 showed mesophyll cell death. The data indicate that, in barley, O2 - accumulation is not a single key determinant of HR in response to a powdery mildew attack.

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