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

To enhance the framework of the mechanisms of action used by Trichoderma gamsii T6085 for the control of Fusarium head blight (FHB), this work investigated its ability to modulate the expression of defence-related genes of wheat (Triticum aestivum 'Apogee') in response to endophytic colonization of plant tissues. Changes in relative expression of pal1, pr1, pgip2 and lox1 genes were assessed over time in wheat roots, in spikes colonized by T6085 alone and both T6085 and Fusarium graminearum, and in leaves from wheat seedlings root-inoculated with T6085. Results indicate the ability of T6085 to induce local and systemic defence responses in wheat plants in the presence of one of the causal agents of FHB. There was a general significant up-regulation of the plant defence-related genes 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 to 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, root colonization was assessed on four cultivars of T. aestivum and two cultivars of T. durum. Data showed that roots of only two T. aestivum cultivars were endophytically colonized by T6085, similar to cv. Apogee used here as control, thus demonstrating an effect of the host genotype on the endophytic ability of T6085.