Rationalising vitamin B 6 biofortification in crop plants.

Vitamin B6 encompasses a group of related compounds (vitamers) that can only be biosynthesised de novo by plants and microorganisms. Enzymatic cofactor and antioxidant functions for vitamin B6 are established in all kingdoms. Human vitamin B6 dietary insufficiency or genetic defects in B6 vitamer interconversion result in various neurological and inflammatory pathologies with several populations at-risk or marginal for vitamin B6 status. Three (rice, wheat and cassava) of the world's top five staple crops do not meet the recommended dietary allowance for vitamin B6 , when consumed as a major proportion of the diet. In addition, controlled enhancement of the appropriate B6 vitamer in crops has the potential to confer stress resistance. Thus, crop biofortification strategies represent an opportunity to reduce the risk of deficiency in populations with limited diet diversity and quality, as well as improving stress tolerance.