Study unravels key mechanism by which Xanthomonas bacteria infect crops

At Nanyang Technological University, Singapore, an interdisciplinary research team has identified, for the first time, a crucial mechanism by which a serious plant disease can infect crops.

(From left to right) Assistant Professor Yu Jing from NTU’s School of Materials Science and Engineering and Associate Professor Miao Yansong from the School of Biological Sciences. Image Credit: Nanyang Technological University, Singapore.

The Xanthomonas bacteria, also called the “crop killer,” is a bacterium found worldwide and capable of infecting 400 different plant species. The infection leads to bacterial spots and blights in the leaves and fruits of the plants. In certain cases, once the disease is rooted, the only recourse option for a farmer is to cut down and burn the entire crop to prevent the spread of disease.

The NTU group discovered the precise cellular-level mechanism used by the bacteria to penetrate and hijack the immune system of a plant, thus leaving them susceptible to infection.

The Xanthomonas bacteria infect and harm plants by infusing harmful proteins into the plant host. These proteins hijack and assume the normal biological processes of the plant, inhibiting them from forging an immune response.

The researchers found that the harmful proteins interact with plant cells like liquid droplets, enabling the bacteria protein to “glue” onto the plant cell and blend into it. This enables the Xanthomonas bacteria to intrude and invade the plant cell, making it susceptible to infection.

Gaining insights into the exact means by which plants and crops are infected by bacteria is a critical step in formulating methods to inhibit their infection and make crops capable of resisting the disease.

The researchers have obtained a provisional patent for a toolkit they created. This enables the researchers to simulate the infection process. This will enable them to test prospective solutions to strengthen crop immunity in laboratory settings. The toolkit also has potential applications for synthetic biology and agri-food technology in the future.