In the present study, we investigated the role of Trichoderma virens 
(TriV_JSB100) spores or cell-free culture filtrate in the regulation of growth 
and activation of the defence responses of tomato (Solanum lycopersicum) plants 
against Fusarium oxysporum f. sp. lycopersici by the development of a 
biocontrol-plant-pathogen interaction system. Two-week-old tomato seedlings 
primed with TriV_JSB100 spores cultured on barley grains (BGS) or with cell-free 
culture filtrate (CF) were inoculated with Fusarium pathogen under glasshouse 
conditions; this resulted in significantly lower disease incidence in tomato 
Oogata-Fukuju plants treated with BGS than in those treated with CF. To dissect 
the pathways associated with this response, jasmonic acid (JA) and salicylic 
acid (SA) signalling in BGS- and CF-induced resistance was evaluated using JA- 
and SA-impaired tomato lines. We observed that JA-deficient mutant def1 plants 
were susceptible to Fusarium pathogen when they were treated with BGS. However, 
wild-type (WT) BGS-treated tomato plants showed a higher JA level and 
significantly lower disease incidence. SA-deficient mutant NahG plants treated 
with CF were also found to be susceptible to Fusarium pathogen and displayed low 
SA levels, whereas WT CF-treated tomato plants exhibited moderately lower 
disease levels and substantially higher SA levels. Expression of the 
JA-responsive defensin gene PDF1 was induced in WT tomato plants treated with 
BGS, whereas the SA-inducible pathogenesis-related protein 1 acidic (PR1a) gene 
was up-regulated in WT tomato plants treated with CF. These results suggest that 
TriV_JSB100 BGS and CF differentially induce JA and SA signalling cascades for 
the elicitation of Fusarium oxysporum resistance in tomato.