The Uka-no-Mitama Defense Virus is a lab-engineered virus that actually protects the hyper-oats from disease and pests.
Hyper-oats are a valuable source of food, but by being of a monopassive gene type, they are highly vulnerable. The Uka-no-Mitama Defense Virus protects the hyper-oats from several destructive forces that could eradicate the entire crop, thus starving the population that depends on it a dietary mainstay. It is highly effective, but less than perfect. The virus is controlled by an automated computer system, so if the target is changed, it will destroy the very crop it's meant to protect.
The Uka-no-Mitama is the invention of agricultural specialist, Nobuaki Kudama. Its sole purpose is to protect his other invention, the hyper-oats, a basic food source for the general population. Because the hyper-oats lack genetic diversity, they are vulnerable to infection and pestilence, thus rendering the foodsource inedible. Makishima kills Kudama in order to gain access to the control facility with the intention of sabotaging the country's food production and forcing society to heed his demands.