Trichoderma gamsii T6085, a biocontrol agent of Fusarium head blight, modulates biocontrol-relevant defence gene expression in wheat.

To enrich the framework of the mechanisms of action Trichoderma gamsii T6085 can use for the control of FHB, in this work its ability to modulate the expression of defence-related genes of wheat (T. aestivum cv Apogee), in response to endophytic colonization of plant tissues, has been investigated. Changes on relative expression of pal1, pr1, pgip2 and lox1 genes were assessed over time in wheat roots and spikes colonized by T6085, also in presence of F. graminearum, and in leaves from wheat seedlings inoculated with T6085 on roots. Results indicate the ability of T6085 to induce local and systemic defence responses in wheat plants also in presence of one of the causal agents of FHB. Results showed a general significant up-regulation of the plant defence-related genes here analysed, especially in the first days after the application of T6085. According to these results, modulation of plant defence genes could be included within the arsenal of mechanisms used by T6085 when applied on wheat, an additional feature of interest in the management of FHB. To evaluate the effect of the plant genotype on the ability of T6085 to endophytically colonize roots, percentages of root colonization were assessed on four cultivars of T. aestivum and two cultivars of T. durum. Data showed that only roots of two T. aestivum cultivars were endophytically colonized by T6085 in a way not significantly different from those of cultivar Apogee, here used as control, thus demonstrating an effect of the host genotype on T6085 endophytic ability.