Local and systemic resistance to fungal pathogens triggered by an AVR9-mediated hypersensitive response in tomato and oilseed rape carrying the Cf-9 resistance gene

2001 ◽  
Vol 59 (6) ◽  
pp. 287-295 ◽  
Author(s):  
Caroline Hennin ◽  
Elke Diederichsen ◽  
Monica Höfte
2005 ◽  
Vol 66 (5) ◽  
pp. 163-174 ◽  
Author(s):  
Nektarios Kavroulakis ◽  
Constantinos Ehaliotis ◽  
Spyridon Ntougias ◽  
Georgios I. Zervakis ◽  
Kalliope K. Papadopoulou

2020 ◽  
Vol 21 (22) ◽  
pp. 8740
Author(s):  
Daria Chlebek ◽  
Artur Pinski ◽  
Joanna Żur ◽  
Justyna Michalska ◽  
Katarzyna Hupert-Kocurek

Endophytic bacteria hold tremendous potential for use as biocontrol agents. Our study aimed to investigate the biocontrol activity of Pseudomonas fluorescens BRZ63, a new endophyte of oilseed rape (Brassica napus L.) against Rhizoctonia solani W70, Colletotrichum dematium K, Sclerotinia sclerotiorum K2291, and Fusarium avenaceum. In addition, features crucial for biocontrol, plant growth promotion, and colonization were assessed and linked with the genome sequences. The in vitro tests showed that BRZ63 significantly inhibited the mycelium growth of all tested pathogens and stimulated germination and growth of oilseed rape seedlings treated with fungal pathogens. The BRZ63 strain can benefit plants by producing biosurfactants, siderophores, indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and ammonia as well as phosphate solubilization. The abilities of exopolysaccharide production, autoaggregation, and biofilm formation additionally underline its potential to plant colonization and hence biocontrol. The effective colonization properties of the BRZ63 strain were confirmed by microscopy observations of EGFP-expressing cells colonizing the root surface and epidermal cells of Arabidopsis thaliana Col-0. Genome mining identified many genes related to the biocontrol process, such as transporters, siderophores, and other secondary metabolites. All analyses revealed that the BRZ63 strain is an excellent endophytic candidate for biocontrol of various plant pathogens and plant growth promotion.


PLoS ONE ◽  
2017 ◽  
Vol 12 (1) ◽  
pp. e0168850 ◽  
Author(s):  
Jawadayn Talib Alkooranee ◽  
Tamarah Raad Aledan ◽  
Ali Kadhim Ali ◽  
Guangyuan Lu ◽  
Xuekun Zhang ◽  
...  

2011 ◽  
Vol 101 (6) ◽  
pp. 732-740 ◽  
Author(s):  
Mee Kyung Sang ◽  
Ki Deok Kim

We investigated direct and indirect effects of compost water extracts (CWEs) from Iljuk-3, Iljuk-7, Shinong-8, and Shinong-9 for the control of anthracnoses caused by Colletotrichum coccodes on pepper and C. orbiculare on cucumber. All tested CWEs significantly (P < 0.05) inhibited in vitro conidial germination and appressorium formation of the fungal pathogens; however, DL-β-amino-n-butyric acid (BABA) failed to inhibit the conidial development of the pathogens. Direct treatments of the CWEs and BABA on pepper and cucumber leaves at 1 and 3 days before or after inoculation significantly (P < 0.05) reduced anthracnose severities; Iljuk-3, Shinong-9, and BABA for pepper and Iljuk-7 for cucumber had more protective activities than curative activities. In addition, root treatment of CWEs suppressed anthracnoses on the plants by the pathogens; however, CWE treatment on lower leaves failed to reduce the diseases on the upper leaves of the plants. The CWE root treatments enhanced not only the expression of the pathogenesis-related (PR) genes CABPR1, CABGLU, CAChi2, CaPR-4, CAPO1, and CaPR-10 in pepper and PR1-1a, PR-2, PR-3, and APOX in cucumber but also the activity of β-1,3-glucanase, chitinase, and peroxidase and the generation of hydrogen peroxide in pepper and cucumber under pathogen-inoculated conditions. However, the CWE treatments failed to induce the plant responses under pathogen-free conditions. These results indicated that the CWEs had direct effects, reducing anthracnoses by C. coccodes on pepper leaves and C. orbiculare on cucumber leaves through protective and curative effects. In addition, CWE root treatments could induce systemic resistance in the primed state against pathogens on plant leaves that enhanced PR gene expression, defense-related enzyme production, and hydrogen peroxide generation rapidly and effectively immediately after pathogen infection. Thus, the CWEs might suppress anthracnoses on leaves of both pepper and cucumber through primed (priming-mediated) systemic resistance.


1995 ◽  
Vol 73 (S1) ◽  
pp. 490-494 ◽  
Author(s):  
Pierre J. G. M. de Wit ◽  
Matthieu H. A. J. Joosten ◽  
Guy Honée ◽  
Paul J. M. J. Vossen ◽  
Ton J. Cozijnsen ◽  
...  

Host genotype specificity in interactions between biotrophic fungal pathogens and plants in most cases complies with the gene-for-gene model. Success or failure of infection is determined by the absence or presence of complementary genes, avirulence and resistance genes, in the pathogen and the host plant, respectively. Resistance, expressed by the induction of a hypersensitive response followed by other defence responses in the host, is envisaged to be based on recognition of the pathogen, mediated through direct interaction between products of avirulence genes of the pathogen (the so-called race-specific elicitors) and receptors in the host plant, the putative products of resistance genes. The interaction between the biotrophic fungus Cladosporium fulvum and its only host, tomato, is a model system to study fungus–plant gene-for-gene relationships. Here we review research on isolation, characterization, and biological function of two race-specific elicitors AVR4 and AVR9 of C. fulvum and cloning and regulation of their encoding genes. Key words: avirulence genes, race-specific elicitors, resistance genes, hypersensitive response, host defense responses.


2005 ◽  
Vol 95 (9) ◽  
pp. 1061-1071 ◽  
Author(s):  
M. H. Balesdent ◽  
M. J. Barbetti ◽  
Hua Li ◽  
K. Sivasithamparam ◽  
L. Gout ◽  
...  

Leptosphaeria maculans, the causal agent of stem canker of oilseed rape, develops gene-for-gene interactions with its hosts. To date, eight L. maculans avirulence (Avr) genes, AvrLm1 to AvrLm8, have been genetically characterized. An additional Avr gene, AvrLm9, that interacts with the resistance gene Rlm9, was genetically characterized here following in vitro crosses of the pathogen. A worldwide collection of 63 isolates, including the International Blackleg of Crucifers Network collection, was genotyped at these nine Avr loci. In a first step, isolates were classified into pathogenicity groups (PGs) using two published differential sets. This analysis revealed geographical disparities as regards the proportion of each PG. Genotyping of isolates at all Avr loci confirmed the disparities between continents, in terms of Avr allele frequencies, particularly for AvrLm2, AvrLm3, AvrLm7, AvrLm8, and AvrLm9, or in terms of race structure, diversity, and complexity. Twenty-six distinct races were identified in the collection. A larger number of races (n = 18) was found in Australia than in Europe (n = 8). Mean number of virulence alleles per isolate was also higher in Australia (5.11 virulence alleles) than in Europe (4.33) and Canada (3.46). Due to the diversity of populations of L. maculans evidenced here at the race level, a new, open terminology is proposed for L. maculans race designation, indicating all Avr loci for which the isolate is avirulent.


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