Flavonoid Biosynthetic Pathway and Cereal Defence Response An Emerging Trend in Crop Biotechnoloy

The flavonoid pathway, derived from the phenylpropanoid and acetyl CoA and malonyl CoA pathways, gives rise to a diverse array of compounds such as isoflavonoids, anthocyanins, proanthocyanidins, etc. that are attributed with a multitude of biological functions. There is an increasing evidence on the role of flavonoids in defence response in many plant species though the exact mechanism is yet to be defined unequivocally. On the contrary, there is very little information on the role of flavonoids in cereal defence response. A novel strategy to improve disease resistance in cereals is by the engineering of the flavonoid pathway for enhancement of specific flavonoids in selected tissue under pathogen attack. Recent developments in molecular biology and genetics of flavonoid pathway in several plants would allow one to test its potential in improving disease resistance. Further, the powerful molecular techniques and reproducible transformation protocols would enable the manipulation of the flavonoid pathway in cereals. Transferring allied pathways, or a part of pathways to target plants seem to be within the reach of many groups. It is. therefore, time for a second look at this secondary pathway particularly in the context of disease resistance phenomenon.