The aim of this project is to develop new methods to study the distribution of bacteria inside plants. Endophytic bacteria will be genetically modified to express fluorescent markers such as GFP (green fluorescent protein) and other markers (other fluorescent proteins, light emitting proteins, specific enzymes) when growing inside plants. The marker strains will be used to map the distribution of bacteria throughout the plant. Also changes in bacterial distribution during pathogen infection can be visualized. The bacterial localization will be studied using imaging techniques such as confocal microscopy.