Fungi blamed for a serious rice disease are in fact not the sole culprits, according to findings that have implications for protecting both a major crop and human health.
The Rhizopus fungi, which live in soil, were thought to produce a toxin that kills the roots of rice plants, causing a disease called 'seedling blight'. The deadly disease costs rice farmers millions of dollars each year in lost harvests.
But research published today (6 October) in Nature says the poison — rhizoxin — comes not from the fungi but from bacteria living inside them.
Laila Partida-Martinez and Christian Hertweck of the Leibniz Institute for Natural Products Research and Infection Biology, Germany, discovered this after realising that the fungi did not have the right genes to produce the toxin.
The researchers found bacteria living inside the fungi. They then proved that the bacteria produce rhizoxin, which breaks down the rice roots and allows the fungus to digest the dead root.
"In principle, it could be possible to control the disease by applying antibacterial — rather than antifungal — agents to protect rice seedlings," Hertweck told SciDev.Net.
Rhizoxin can stop root cells from multiplying. In the same way, it can also stop the growth of some human cancer cells, and is being studied as a potential cancer treatment.
Link to full paper in Nature
Link to commentary in Nature