چکیده : 

The Fusarium wilt in cucumbers, caused by the pathogenic fungus Fusarium oxysporum f. sp. cucumerinum,is a serious and destructive disease worldwide. An effort was made to explore the role of Trichodermaharzianum T-E5 in reducing the incidence of Fusarium wilt. Three treatments (Control, T1, and T2) wereestablished in the greenhouse experiment. The effects of T-E5 on the composition of root exudates andfungal community in the cucumber rhizosphere were measured. Compared with the control, the applica-tion of a bio-organic fertilizer (BIO) enriched with T-E5 was found to decrease the incidence of Fusariumwilt notably and promote the growth of cucumber plants. Based on real-time PCR, the population of F.oxysporum in the control without T-E5 increased from 103to 104ITS copies g−1soil, whereas the popu-lation decreased from 103to 102ITS copies g−1soil in the T1 and T2 treatment groups when T-E5 wasincluded. Significant difference in fungal community was also found among the treatment groups. HPLCanalysis showed that the detected levels of phenolic compounds in control were significantly higher thanthe levels in the samples subjected to T1 and T2 treatments. The root exudates from the control groupsignificantly increased the numbers of germinating spores of the pathogen compared with those fromthe samples treated with T1 and T2. In conclusion, the modification of root exudates and the fungal com-munity by the application of BIO might account for the effective suppression of Fusarium wilt disease incucumbers.