Fungi have been subjected to genetic engineering in various ways. Agrobacterium tumefaciens-mediated transformation (AtMT) is an important method for the genetic manipulation of different fungal species. Here, gene transfer to Trichoderma viridescens was performed and optimized using A. tumefaciens strain pSDM2315. Also, the effect of different temperatures on the growth and conidiation rates of the wild-type and transformed fungi was investigated. The results indicated that the best conditions for maximum transformation in T. viridescens were the combination of one day of incubation, 28˚C, pH 5.0, and a concentration of 107 conidia mL-1. The results of gene transfer and stable expression of transgenes were confirmed using sequential culture in selective media and PCR. Moreover, the mycelial growth of transformed fungi at different temperatures did not show an obvious difference from the wild-type, but the mutants produced different numbers of conidia. This indicates the potential of AtMT for functional mutagenesis and physiological studies in T. viridescens.
