Flavonoids are the largest group of secondary metabolites that function in plants to protect it against various stresses. Theirs occurrence in human diet also plays an important role in health protection by preventing oxidative stress that leads to degenerative diseases. To develop a system in tobacco that would yield flavonoid, the research team at King Mongkut’s Institute of Technology Ladkrabang, Thailand developed transgenic tobacco to over express transparent testa 8 (TT8) gene obtained from Arabidopsis thaliana. The TT8 gene contains a sequence that can elevate the expression of a gene in the flavonoid biosynthesis.

Genetic screening using Polymerase Chain Reaction of regenerated tobacco plantlets yielded 20 transgenic plants that contain TT8 cDNA. Varying levels of flavonoid expression were obtained from four-week old transgenic plants when induced for 7 days under fluorescent light combined with long wave UV at 500 lux intensity. Flavonoid expression was based on the presence and quantity of flavonoids: naringenin, apigenin, kaemferol, gallotannin and pelagonidin. All transgenic lines contain naringenin and apigenin at 4-folds higher than the wild type. Moreover, there were transgenic lines that express both substances at 15-folds higher than the wild type. Flavonoids kaemferol, gallotannin and pelagonidin were also expressed in some transgenic lines, 7-9 folds higher than that of wild type. The differential expression of the TT8 cDNA can be due to positional effect in gene integration.

For details, see the article at: http://www.safetybio.agri.kps.ku.ac.th/index.php?option=com_content&task=view&id=4300&Itemid=47 . For information on biotechnology in Thailand, contact Supat Attathom at: safetybio@yahoo.com..