Engineer Bacterial Infection Process

The nitrogen-fixing bacteria colonise the legume root and ultimately end up within plant membrane-bound compartments in the cells of the nodule.

Intracellular accommodation of the bacteria appears to be critical for efficient nitrogen-fixation, but this is likely to be the hardest step of this process to engineer into cereals.

Bacterial infection is initiated at the root surface and the bacteria allowed entry into the root cells via tubular invaginations of the cells, called infection threads.

The detailed molecular mechanisms that produce an infection thread remain unclear, however, continued perception of Nod factor from the bacteria is an important driver of this process.

This image shows a root hair infected by Sinorhizobia meliloti (purple). Live cell imaging such as this enables us to trace the cellular dynamics of rhizobial infection.

Genetic and cell biological evidence points at commonalities between infection of rhizobial bacteria and the infection of arbuscular mycorrhizal fungi. Hence, in a manner analogous to the engineering of Nod factor perception in cereals, we believe that we can utilise pre-existing protein complexes within cereals to engineer rhizobial infection.

Some of the proteins involved in rhizobial infection are also required for mycorrhizal Infection. The existence of such components in cereal plants lays another foundation for engineering rhizobial infection.

We are exploring how much we can use the pre-existing molecular machinery present in cereals that allows mycorrhizal infection to engineer a new capability of rhizobial infection.