Fusarium culmorum Infection of Barley Seedlings: Correlation between Aggressiveness and Deoxynivalenol Content

Abstract

Fusarium culmorum is a serious plant pathogen, especially on cereals. The production of deoxynivalenol (DON) by F. culmorum is believed to play a role in pathogenesis. This relationship has been almost exclusively studied in connection with head blight. The present paper reports the first finding of DON in cereal seedlings infected with F. culmorum. A pathogenicity test was performed, including 70 isolates of this pathogen from different sites within northern and central Europe. All isolates caused disease on barley seedlings. For 15 isolates with varying aggressiveness, the DON content in the 19‐day‐old‐barley seedlings was determined. There was a significant correlation between DON concentration and disease index. The aggressiveness of two outlying isolates with very low DON production is discussed. The results indicate that for F. culmorum isolates of the DON chemotype, production of this toxin influences the aggressiveness of the isolates towards barley seedlings.

Interactions between Head Blight Pathogens: Consequences for Disease Development and Toxin Production in Wheat Spikes

“…In the greenhouse experiments, the correlation between the fungal biomass (estimated by DNA quantification) and HB severity (AUDPC) was strong and positive, in agreement with other studies using similar techniques (6,18,19). A good correlation between fungal biomass and HB severity is expected when the inoculations are performed at the most receptive stage of the host plant, which was the case in both our greenhouse and our field study.…”

Association of mating-type with mycelium growth rate and genetic variability of Fusarium culmorum

“…All DON-producing isolates of F. culmorum have mutations in the Tri-7 gene that have been shown to be conserved across the species [15]. It is known that for F. culmorum isolates displaying the DON chemotype, production of this toxin influences the aggressiveness of the isolates towards barley seedlings [7]. Our results concur with epidemiological studies Estimates of regression coefficients…”

“…Trichothecene biosynthesis is a complex process, controlled by several Tri genes [1]. Trichothecenes are involved in virulence; disruption of the trichodiene synthase gene reduces virulence [6,7]. It was recently that the translocation of DON from the stem base to the head following infection by F. culmorum forms an additional route for the contamination of cereal-derived food by the mycotoxin [8,9].…”

Interactions of Fusarium species during prepenetration development

“…Competitive advantages of a species could range from the number of conidia produced to its adaptability to a wide temperature range. Mycotoxins and other secondary metabolites produced by a species may also play a role (Llorens et al 2006;Hestbjerg et al 2002;Mesterhazy 2002). Beyer et al (2004) observed emergence of germ tubes of F. graminearum after 2 to 6 hours on glass surface at 20 C, but it was delayed by about 2 hours at 14 C. This is supported by our results where the lower temperature aggravated delay in germination.…”