Méthodologie de criblage rapide in vitro de l’activité antifongique de substances naturelles bioactives sur cultures Pathogénicité, production de trichotécènes par Fusarium culmorum et évaluation de la résistance des variétés de blé cultivées en Algérie

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Méthodologie de criblage rapide in vitro de l’activité antifongique de substances naturelles bioactives sur cultures Pathogénicité, production de trichotécènes par Fusarium culmorum et évaluation de la résistance des variétés de blé cultivées en Algérie

International audienc

Pathogenicity and trichothecenes production of Fusarium culmorum strains causing head blight on wheat and evaluation of resistance of the varieties cultivated in Algeria

International audienceFusarium head blight (FHB) is a major disease of wheat that has been studied worldwide but never in Algeria where high quantities of both durum wheat and common soft wheat are grown and traditionally consumed as semolina and bread. Fusarium root rot has also been observed in this country. Here we show that Fusarium culmorum seems to be the major pathogen associated with these diseases in Algeria. The type of mycotoxins produced by four F. culmorum isolates and their capacity to confer the disease on spike and accumulate type B trichothecenes in the grain was evaluated. Two strains produced deoxynivalenol, 3-acetyldeoxynivalenol and zearalenone in vitro. The two other strains produced nivalenol and fusarenone X. The four strains were used for artificial spray inoculations on wheat spikes to determine their potential in generating FHB symptoms and accumulating mycotoxins in local field conditions. A panel constituted of four durum wheat and four soft wheat varieties generally cultivated in Algeria and of two newly created durum wheat lines were evaluated. The results show a correlation between the level of invasion of the grain and the quantity of accumulated toxins with a large diversity depending on the cultivars. Interestingly, two local durum wheat varieties and the two new durum lines showed a promising level of resistance to FHB with significantly lower trichothecene accumulation. The content in phenolic compounds of the different varieties was assessed and evaluated as possible factor of resistance to trichothecene accumulation. This is the first report evaluating the wheat varieties cultivated in Algeria for their susceptibility to Fusarium Head Blight caused by local strains of F. culmorum in semi-arid bioclimatic condition

Phenotypic and biochemical characterization of new advanced durum wheat breeding lines from Algeria that show resistance to fusarium head blight and to mycotoxin accumulation

International audienceDurum wheat (Triticum turgidum L. var. durum) is a crop highly susceptible to Fusarium head blight (FHB), which results in yield losses and downgrades the quality of grains mostly due to mycotoxin contamination. Although breeding for resistance to FHB is one of the most promising strategy for minimizing crop damage, the attempts to obtain durum wheat resistant lines have been limited so far. Two potentially interesting lines were recently delivered by a breeding program based on crosses involving cultivars from Europe and Syria. Using a field experiment in Algeria with four different Fusarium culmorum strains and a spray inoculation method, we demonstrated that the two breeding lines were significantly less affected than a set of commercial cultivars. The two breeding lines were shown to exhibit a higher resistance to both initial fungal infection and disease spread , and to mycotoxin contamination. In addition, a detailed analysis of 2 phenolic acid composition of grains indicates significant differences in p-coumaric acid between the FHB-resistant breeding lines and the sensitive genotypes. Our results corroborate the importance of cell wall composition in preventing the diffusion of F. culmorum and therefore contributing to the resistance of cereals to FHB