Martin Parniske is investigating the interaction between plants and symbiotic or pathogenic microorganisms. State of the art genetical, biochemical, and cell biological methods are used to elucidate the molecular processes that lead to the cellular reprogramming and redifferentiation associated with mutual compatibility or defence. Likewise, he explore natural diversity and ecological approaches to identify allelic variation governing agriculturally important traits, like efficiency of nitrogen fixation, nutrient uptake, or disease resistance. These aspects are fundamental for the fight against plant pathogens and the optimised utilisation of beneficial plant-microbe symbioses and on the background of depleting natural resources.