Vector Integration in Triple R gene Transformants for Potato Late Blight Resistance

The use of resistance (R) genes in genetic engineering is a potential technique to improve resistance stability against pathogens such as potato late blight (Phytophthora infestans). Scientist Suxian Zhu from Wageningen University and team analyzed 128 potato transformants to identify if vector T-DNA genes, borders, and backbone sequences were present. The transformants were developed using a construct containing neomycin phosphotransferase II (nptII) and three R genes against potato late blight.

Results of the team's analysis showed that 45 percent of the R-expressing transformants had low T-DNA copy number, without the integration of vector backbone and borders. They characterized the integration of vector backbone sequences using eight genes, with tetA used for early prediction of plants with backbone sequence integration. Two transformants were crossed with Katahdin, a potato cultivar susceptible to potato late blight. The results implied that all four T-DNA genes were inherited together and followed Mendel's law of segregation. All R genes were also found to be functionally expressed in the offspring plants just like in the parental transformants. The research team concluded that functional gene stacking is important for developing more successful resistance against potato late blight.

Read the abstract at http://www.springerlink.com/content/y1676654043575j1/.