Cassava (Manihot esculenta), a major staple food in the developing world, provides a basic
carbohydrate diet for over half a billion people living in the tropics. Despite the iron
abundance in most soils, cassava provides insufficient iron for humans as the edible roots
contain 3–12 times less iron than other traditional food crops such as wheat, maize, and rice.
With the recent identification that the beneficial soil bacterium Bacillus subtilis (strain
GB03) activates iron acquisition machinery to increase metal ion assimilation in Arabidopsis,
the question arises as to whether this plant-growth promoting rhizobacterium also augments
iron assimilation to increase endogenous iron levels in cassava. Biochemical analyses reveal
that shoot-propagated cassava with GB03-inoculation exhibit elevated iron accumulation
after 140 days of plant growth as determined by X-ray microanalysis and total foliar iron