Transgenic Potato (Solanumtuberosum) Expressing Two Antifungal Thionin Genes Confer Resistance To Fusarium Spp.

Abstract

Two thionin genes were isolated from Arabidopsis thaliana (AT1G12660 and AT1G12663). The resulted thionin protein has antifungal activity against potato pathogenic fungi like Fusariumsolani and Fusariumoxysporum. These two thionin genes were respectively inserted into pEGAD vector. After that transformed into Agrobacterium tumifaceins GV3101::pMP90 in order to be transformed into the two potato cultivars (lady and spunta) using nodal cutting technique of tissue culture.Expressions of thionin transgenes in the transgenic plants were confirmed by RT-PCR. There were two assays were applied to test the role of thionins (in the transgenic potatoes) in resistance to the pathogenic fungi: effect of spore suspension on potato organs and the inhibitory effect of thionin proteins on spore germination.As the transgenic potato plant possesses active defense systems and can protect themselves from pathogenic invasion by secretion of a variety of small antifungal proteins such as thionins. The resulted transgenic potato cultivars were tested for fungal infection in comparing to control by using spore suspension on leaf and micro-tuber. The results showed that transgenic potato cultivars were highly resistant to the symptoms comparing to control.The other bioassay was studying the effect of the expressed thionin protein in the transgenic potato against the spore germination of both F. solani and F. oxysporum. There was obvious decrease in the number of the germinated spores comparing to control.