Agrobacterium tumefaciens-mediated transformation of SOD gene to Trichoderma harzianum

Trichoderma harzianum is a soil-borne filamentous fungus that exhibits biological control properties because it parasitizes a large variety of phytopathogenic fungi. In this study the SOD gene was successfully transferred into the bio-control fungus Trichoderma harzianum with an efficiency of 60-110 transformants per 10(7) spores by using Agrobacterium tumefaciens-mediated transformation. Putative transformants were analyzed to test the transformation by the southern blot. Antifungal activities of the transformants were examined under abiotic stresses. The transformants were exposed to 40A degrees C for three days and 2 mol/l NaCl at 27A degrees C for 5-10 days to assay antifungal activities with Sclerotinia sclerotiorum. The inhibition rates of the transformants, comparing to Trichoderma harzianum with no SOD gene transferred, were respectively 83.96% after 40A degrees C and 60.13% after 2 mol/l NaCl. The results showed that the SOD transformants had significantly higher resistance to heat and salt stress.