Nitrogen limitation induces expression of the avirulence gene avr9 in the tomato pathogen Cladosporium fulvum

1994 ◽  
Vol 243 (3) ◽  
pp. 277-285 ◽  
Author(s):  
G. F. J. M. Van den Ackerveken ◽  
R. M. Dunn ◽  
A. J. Cozijnsen ◽  
J. P. M. J. Vossen ◽  
H. W. J. Van den Broek ◽  
...  
1998 ◽  
Vol 11 (4) ◽  
pp. 301-308 ◽  
Author(s):  
Richard Laugé ◽  
Alexander P. Dmitriev ◽  
Matthieu H. A. J. Joosten ◽  
Pierre J. G. M. De Wit

The existence of a gene or genes conferring weak resistance against the fungal tomato pathogen Cladosporium fulvum, in addition to the Cf-9 resistance gene, present on the Lycopersicon pimpinellifolium Cf-9 segment introgressed into L. esculentum, was demonstrated with strains of C. fulvum lacking a functional Avr9 avirulence gene and tomato genotypes lacking a functional Cf-9 gene, respectively. Two mutant strains, obtained by disruption of Avr9 in race 4 and race 5 of C. fulvum, do not trigger the hypersensitive response-mediated resistance on MM-Cf9 genotypes that is normally induced after recognition of the AVR9 elicitor. However, when these strains are inoculated onto MM-Cf0 and MM-Cf9 genotypes, adult MM-Cf9 plants still show weak resistance. This resistance is not related to the Cf-9 gene, as ethyl methanesulfonate (EMS)-generated Cf-9 mutants retained weak resistance. Growth of the fungus in the leaf mesophyll is strongly inhibited, whereas re-emergence of fungal mycelium and conidiation are poor. Strong accumulation of pathogenesis-related proteins and early leaf chlorosis are associated with this phenotype of weak resistance. A search among natural strains lacking the Avr9 gene revealed that one strain is able to overcome this weak resistance. Possible mechanisms underlying this weak resistance are discussed. The presence of the additional weak resistance gene(s) could explain why the resistance of Cf9 genotypes has not been overcome so far in practice.


PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e85877 ◽  
Author(s):  
Jérôme Collemare ◽  
Scott Griffiths ◽  
Yuichiro Iida ◽  
Mansoor Karimi Jashni ◽  
Evy Battaglia ◽  
...  

1994 ◽  
Vol 26 (3) ◽  
pp. 245-250 ◽  
Author(s):  
Roland Marmeisse ◽  
Guido F. J. M. Van den Ackerveken ◽  
Theo Goosen ◽  
Pierre J. G. M. De Wit ◽  
Henk W. J. Van den Broek

1998 ◽  
Vol 11 (3) ◽  
pp. 228-236 ◽  
Author(s):  
Rachel E. Melton ◽  
Lynda M. Flegg ◽  
James K. M. Brown ◽  
Richard P. Oliver ◽  
Michael J. Daniels ◽  
...  

The anti-fungal, steroidal, glycoalkaloid saponin, α-tomatine, is present in uninfected tomato plants in substantial concentrations, and may contribute to the protection of tomato plants against attack by phytopathogenic fungi. In general, successful fungal pathogens of tomato are more resistant to α-tomatine in vitro than fungi that do not infect this plant. For a number of tomato pathogens, this resistance has been associated with the ability to detoxify α-tomatine through the action of enzymes known as tomatinases. In contrast, the biotrophic tomato pathogen Cladosporium fulvum is sensitive to α-tomatine and is unable to detoxify this saponin. This paper describes the effects of heterologous expression of the cDNA encoding tomatinase from the necrotroph Septoria lycopersici in two different physiological races of C. fulvum. Tomatinase-producing C. fulvum transformants showed increased sporulation on cotyledons of susceptible tomato lines. They also caused more extensive infection of seedlings of resistant tomato lines. Thus, α-tomatine may contribute to the ability of tomato to restrict the growth of C. fulvum in both compatible and incompatible interactions.


Nature ◽  
1994 ◽  
Vol 367 (6461) ◽  
pp. 384-386 ◽  
Author(s):  
Matthieu H. A. J. Joosten ◽  
Ton J. Cozijnsen ◽  
Pierre J. G. M. De Wit

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