scholarly journals Induction of defence reactions in plants

1987 ◽  
Vol 59 (3) ◽  
pp. 231-249
Author(s):  
Hans Thordal-Christensen ◽  
Per L. Gregersen ◽  
Jan B. Andersen ◽  
Viggo Smedegaars-Petersen
Keyword(s):  
Powdery Mildew ◽  
Induced Resistance ◽  
De Novo ◽  
Specific Resistance ◽  
Epidermal Cells ◽  
Barley Powdery Mildew ◽  
Time Of Infection ◽  
Induce Resistance ◽  
Plant Pathogen Interactions ◽  
Cultivar Specificity

Induced local resistance presumably involves the same mechanisms in the plants as resistance elicited during normal plant-pathogen interactions. In many cases resistance elicitors from pathogens have been found to be non-specific, i.e. unrelated to race-cultivar specificity. Thus, existence of specific resistance suppressors has been suggested to make the virulent races able to infect. In other cases specific resistance elicitors have been indicated to exist in a virulent races, by which the race specific resistance may be accomplished. At our Department resistance has been induced in the barley—powdery mildew interaction by use of double inoculation procedures. Both virulent and avirulent races of barley powdery mildew can induce resistance, but avirulent races show an increased resistance induction ability in relation to virulent races from 12 hours after inoculation. In barley plants wheat powdery mildew induced more resistance than barley powdery mildew 1 to 8 hours after inoculation. Induced resistance was mainly localized to the epidermal cells attacked by the inducer, but an effect was also present in the surrounding epidermal cells. The energetic consequences of resistance in barley to barley powdery mildew have been found to be reflected in an increased respiratory rate at the time of infection attempt. Further, these energy costs appeared to reduce grain yield by 7 %. The expression of resistance in barley is thought to involve de novo synthesis mRNAs and proteins, which makes it possible to apply gene technological methods to study induced resistance. Research of this kind is in progress at our Department, which hopefully will give information on the mechanisms of resistance triggering and resistance expression.

Recombination of alleles conferring specific resistance to powdery mildew at the Mla locus in barley

Genome ◽  
1994 ◽  
Vol 37 (3) ◽  
pp. 460-468 ◽  
Author(s):  
Mamatha Mahadevappa ◽  
Richard A. DeScenzo ◽  
Roger P. Wise
Keyword(s):  
Powdery Mildew ◽  
Storage Proteins ◽  
Specific Resistance ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Genetic Distances ◽  
Hordeum Vulgare L ◽  
Powdery Mildew Fungus ◽  
Barley Powdery Mildew ◽  
Mla Locus

In barley (Hordeum vulgare L.), the Mla locus conditions reaction to the powdery mildew fungus Erysiphe graminis f.sp. hordei. Enrichment for genetic recombinants in the Mla region is possible by screening for recombination events between the flanking endosperm storage proteins hordeins C and B. Reciprocal crosses were made between the Franger (C.I. 16151) and Rupee (C.I. 16155) lines carrying the (Mla6 + Mla14) and Mla13 alleles, respectively. Recombinants were identified from F2 segregants by analyzing the extracted hordein polypeptides by sodium dodecyl sulphate – polyacrylamide gel electrophoresis. Two hundred and seventy-six recombinant gametes were identified from the 1800 seeds that were screened. Recombination of Mla alleles was analyzed by inoculating F4 recombinant lines with three isolates of E. graminis (A27, 5874, and CR3), which recognize specific Mla alleles. The linkage order established is Hor1–Mla6–Mla13–Mla14–Hor2. The genetic distances between Hor1–Mla6, Mla6–Mla13, and Mla13–Hor2, obtained using Mapmaker 3.0b F3 intercross analysis, are 3.9, 0.2, and 5.2 cM, respectively.Key words: recombinant, barley, powdery mildew, Mla, hordein.

scholarly journals Virulence spectra determination in selected Blumeria graminis f. sp. hordei isolates

2010 ◽  
Vol 58 (5) ◽  
pp. 83-90
Author(s):  
Antonín Dreiseitl ◽  
Petra Adamcová
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Specific Resistance ◽  
Pathogen Population ◽  
The Czech Republic ◽  
Barley Powdery Mildew ◽  
Significant Step ◽  
Complete Set ◽  
Powdery Mildew Pathogen

Virulence spectra for 14 isolates of the barley powdery mildew pathogen considered to be added to the pathogen genebank were determined. The isolates were obtained from a sample of aerial pathogen population collected across the Czech Republic in 2009. The spectra were determined on 28 barley varieties, possessing mostly specific resistance genes and inoculated with the isolates exa­mi­ned. Based on differentiation among each other, all 14 isolates showed their originality. None of the isolates exhibited increased pathogenicity to a variety with the non-specific resistance gene mlo9. All isolates were virulent on varieties carrying specific resistance genes Mla8 and Mlra, and in contrast, none of the isolates was virulent on a variety with the gene Mla23 and with a combination of genes Mla3, MlaTu2. Required characters, such as virulence on the resistance Lv or avirulence on the gene Mlh, were confirmed in some isolates. The results represent a significant step toward obtaining a complete set of information about every isolate before its including in the working genebank of the pathogen.

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

scholarly journals Volatile-mediated signaling induces resistance of barley against infection with the biotrophic fungus Blumeria graminis f.sp. hordei

2021 ◽  
Author(s):  
Silvana Laupheimer ◽  
Reinhard Proels ◽  
Sybille B. Unsicker ◽  
Ralph Huckelhoven
Keyword(s):  
Powdery Mildew ◽  
Fungal Infection ◽  
Induced Resistance ◽  
Biotic Stress ◽  
Green Leaf Volatiles ◽  
Mechanical Wounding ◽  
Hordeum Vulgare L ◽  
Leaf Volatiles ◽  
Enhanced Resistance ◽  
Barley Powdery Mildew

Plants have evolved a vast variety of secondary metabolites to counteract biotic stress. Volatile organic compounds (VOCs) are carbon-based molecules induced by herbivore attack or pathogen infection. A mixture of plant VOCs is released for direct or indirect plant defense, plant-plant or plant-insect communication. Recent studies suggest that VOCs can also induce biotic stress resistance in distant organs and neighboring plants. Among other VOCs, green leaf volatiles (GLVs) are quickly released by plant tissue after the onset of herbivory or wounding. We analysed VOCs emitted by 13-day old barley plants (Hordeum vulgare L.) after mechanical wounding using passive absorbers and TD-GC/MS detection. We investigated the influence of pure (Z)-3-hexenyl acetate (Z3HAC) as well as complex VOCs from wounded barley plants on the barley - powdery mildew interaction by pre-exposure in a static and a dynamic headspace connected to a powdery mildew susceptibility assay. GLVs dominated the volatile profile of wounded barley plants with Z3HAC as the most prominent compound. Pre-exposure with Z3HAC resulted in induced resistance of barley against fungal infection. Barley complex volatiles emitted after mechanical wounding, similarly, enhanced resistance in receiver plants. We found volatile-induced modification of the interaction towards an enhanced resistance against fungal infection. In addition, Z3HAC triggered a modulation of the alcohol dehydrogenase isoenzyme activity in receiver plants, a physiological response that possibly contributes to induced resistance. Plant-originated volatile metabolites could be a useful supplementation for future agronomic or horticultural practices.

scholarly journals De novo indol-3-ylmethyl glucosinolate biosynthesis, and not long-distance transport, contributes to defence of Arabidopsis against powdery mildew

2019 ◽  
Author(s):  
Pascal Hunziker ◽  
Hassan Ghareeb ◽  
Lena Wagenknecht ◽  
Christoph Crocoll ◽  
Barbara Ann Halkier ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Broad Spectrum ◽  
De Novo ◽  
Epidermal Cells ◽  
Host Cells ◽  
Long Distance ◽  
Glucosinolate Biosynthesis ◽  
Golovinomyces Orontii ◽  
Long Distance Transport ◽  
Wide Range

AbstractPowdery mildew is a fungal disease that affects a wide range of plants and reduces crop yield worldwide. As obligate biotrophs, powdery mildew fungi manipulate living host cells to suppress defence responses and to obtain nutrients. Members of the plant order Brassicales produce indole glucosinolates that effectively protect them from attack by non-adapted fungi. Indol-3-ylmethyl glucosinolates are constitutively produced in the phloem and transported to epidermal cells for storage. Upon attack, indol-3-ylmethyl glucosinolates are activated by CYP81F2 to provide broad-spectrum defence against fungi. How de novo biosynthesis and transport contribute to defence of powdery mildew-attacked epidermal cells is unknown. Bioassays and glucosinolate analysis indicate that GTR glucosinolate transporters are not involved in antifungal defence. Using quantitative live-cell imaging of fluorophore-tagged markers, we show that accumulation of the glucosinolate biosynthetic enzymes CYP83B1 and SUR1 is induced in epidermal cells attacked by the non-adapted barley powdery mildew Blumeria graminis f.sp. hordei. By contrast, glucosinolate biosynthesis is attenuated during interaction with the virulent powdery mildew Golovinomyces orontii. Interestingly, SUR1 induction is delayed during the Golovinomyces orontii interaction. We conclude that epidermal de novo synthesis of indol-3-ylmethyl glucosinolate contributes to CYP81F2-mediated broad-spectrum antifungal resistance and that adapted powdery mildews may target this process.

scholarly journals Variety resistance of winter barley to powdery mildew in the field in 1976−2005

2008 ◽  
Vol 43 (No. 3) ◽  
pp. 87-96 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Powdery Mildew Resistance ◽  
Specific Resistance ◽  
Winter Barley ◽  
Mildew Resistance ◽  
Average Resistance ◽  
The Difference ◽  
The Given ◽  
Resistance Of Varieties

The results of evaluation of powdery mildew resistance in winter barley varieties in 285 Czech Official Trials conducted at 20 locations were analysed. Over the period, the number of varieties tested per year increased from four to seven in 1976−1985 to 53−61 in 2002−2005. To assess the resistance of varieties, only trials with sufficient disease severity were used. In 1976−2000, six varieties (1.7% of the varieties tested in the given years) ranked among resistant (average resistance of a variety in a year > 7.5) including NR-468 possessing the gene <i>Mla13</i>, KM-2099 with <i>mlo</i> and Marinka with the genes <i>Mla7</i>, <i>MlaMu2</i>. In 2001−2005, already 33 varieties (16.9%) ranked among resistant, of which Traminer possessing the genes <i>Ml(St)</i> and <i>Ml(IM9 </i> dominated. The proportion of susceptible varieties (average resistance ≤ 5.5) did not change in the two mentioned periods. Two-rowed varieties began to be tested as late as in 1990 (the first variety was Danilo), however, no difference was found in the resistance of two- and six-rowed varieties. Using an example of two pairs of varieties (Dura-Miraj and Marinka-Tiffany) with identical genes for specific resistance but with different resistance in the field, the efficiency of non-specific resistance is discussed. The resistance of domestic and foreign varieties was similar in 1994−2000; however, in 2001−2005 the difference was 0.75 point to disadvantage of domestic ones.

scholarly journals Dissimilarity of barley powdery mildew resistances Lomerit and Heils Hanna

2011 ◽  
Vol 47 (No. 3) ◽  
pp. 95-100 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Agricultural Research ◽  
Blumeria Graminis ◽  
The Other ◽  
Japanese Isolate ◽  
Agricultural Research Institute ◽  
Reaction Type ◽  
Barley Cultivars ◽  
Barley Powdery Mildew ◽  
Old Japanese

&nbsp; The resistance Heils Hanna (HH) was postulated in several tens of 471 previously tested winter barley cultivars. In this paper, new tests on 29 of these cultivars are reported. Thirty-two reference isolates of Blumeria graminis f.sp. hordei held in the pathogen genebank at the Agricultural Research Institute in Kromeriz, Ltd. including a Japanese isolate and five Israeli isolates were used for response tests. However, the resistance HH conferred by the gene Mla8 and herein characterised by reaction type 0 to an old Japanese isolate known as Race I was now postulated only in four cultivars. In the other 25 cultivars another resistance, characterised by reaction type 0 to Race I and also to two Israeli isolates, was detected. In addition to the two mentioned resistances, eight known (Bw, Dr2, Ha, IM9, Ln, Lv, Ra and Sp) resistances were found in the set examined. Lomerit was the only registered cultivar tested here in which the newly detected resistance was present alone, therefore, it is recommended that this resistance be designated Lo.

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