HHU's rice team is part of the Healthy Crops Project, an international research program funded by the Bill & Melinda Gates Foundation.

The goal of the project is to provide significant yield increases for small-scale producers in Africa and Asia by providing disease-resistant rice varieties.

To achieve this goal, we have developed a strategy to combat bacterial blight (BB), one of the most devastating rice diseases, with significant impact on small-scale producers in low- and middle-income countries. The disease is caused by the bacterium Xanthomonas oryzae pv. oryzae (Xoo) and is one of the biggest problems in rice production, with yield losses of up to 70% in severe cases.

When Xoo infects rice, the production of sugar transporters called SWEETs increases sharply in the leaves. The more SWEETs produced, the more sugar is exported from the plant into the extracellular space, which the bacteria feed on, multiply, and ultimately cause the disease.

To make rice plants permanently resistant to bacterial blight, we close the back door that the Xoo bacteria discovered and exploited - the excessive activation of SWEETs. We do this by preventing the bacterial effectors from binding to the SWEET promoters. The devil is in the details. Each Xoo strain has its own set of keys to open the SWEET backdoor. Sometimes, when one key does not work, they switch to another key and induce the production of an alternative SWEET transporter. To achieve broad-spectrum resistance to different Xoo strains, we need to know the TAL effectors that a particular Xoo strain uses to activate the different rice SWEET transporters.