Molecular interaction between Trichoderma virens and tomato roots

The ability of Trichoderma spp. to antagonise plant pathogens, to induce plant resistance and to promote growth in plants has been widely described. Endo-PG produced by Trichoderma spp. can assist root penetration and play a pre-eliciting role in systemic resistance (SIR), a beneficial effect detected in plants colonised by Trichoderma. Two endo-PG genes (eptv1 and eptv2) have been identified and partially characterised in a T. virens isolate, I10, previously investigated for its antagonistic ability in several biological systems. A GFP transformant, I10GFP, derived from the same isolate was exploited to monitor the tomato root colonisation process and to define suitable timing for further experiments. An expression analysis has pointed out a different regulation of those genes. The eptv1 gene resulted induced when the fungal isolate was grown in liquid cultures supplemented by pectin or plant cell walls and when it was applied to tomato roots in growth chamber. Expression times were comparable in both systems. The eptv2 gene resulted constitutively expressed in all conditions tested, including controls. Root exudates showed a promoting effect both on mycelial growth and on conidia germination of T. virens I10. Further mechanisms of the molecular communication between tomato roots and T. virens mycelium are under investigation.