There’s a microscopic fungus that can starve nations and punch through Kevlar. It kills on such as scale that its effects can be seen from space. It’s called Magnaporthe oryzae and it causes a disease known as rice blast. The fungus doesn’t infect humans, but it does kill rice. It kills a lot of rice, destroying up to 30 per cent of the world’s total crop every year – enough to feed 60 million people. Slowly, scientists have worked out how this cereal killer claims its victims.
A rice plant’s woes begin when one of the fungal spores lands on its leaves. As soon as it is surrounded by water, the spore sprouts a dome-shaped structure called the appressorium. This is infection HQ – it’s what the fungus uses to break into the plant. Once inside, it reproduces, eventually causing lesions that kill the leaf.
The appressorium produces glycerol as it grows, which lowers the relative amount of water inside the dome, and draws water in from outside. This builds up enormous pressure, around 40 times more than that within a car tyre. That pressure is directed into a narrow ‘penetration peg’ that travels through a pore at the bottom of the dome, and pierces the helpless plant.