Evaluation of Fusarium graminearum growth and Deoxynivalenol content in susceptible and tolerant varieties of Triticum aestivum

The aim of this work was to verify if the wheat susceptibility/tolerance phenotype to Fusarium head blight (FHB) into the field could be related to the ability of the re-activated seeds to hamper deoxynivalenol (DON) synthesis by Fusarium graminearum into non optimal (i.e. high humidity) storage conditions. On this purpose, two Fusarium graminearum strains, Fg126 and Fg8308, were separately inoculated on active but not germinating kernels of Triticum aestivum L. cv “Sagittario” (FHB-susceptible) and cv “Blasco” (FHB-tolerant). The growth of the fungal strains on wheat kernels was monitored from 0 to 15 days post inoculation through a quantitative SYBR green real-time PCR, as well as ergosterol content through HPLC for comparison. DON biosynthesis into the contaminated wheat seeds was quantified by HPLC method in the same time intervals as above. Significant differences in the ability to grow and synthesize DON, acetylated and glucosylated forms, emerged between the strains also in relation to the wheat variety on which the pathogen developed. The results obtained indicated that the wheat variety which from the epidemiological studies carried out into the field is FHB-tolerant, i.e. Blasco, resulted as the more efficient in hampering DON synthesis in both F. graminearum strains. Thus, this preliminary study could represent a contribution to find out less time consuming methods for screening the wheat varieties tolerant to DON accumulation in non optimal storage conditions.