Molecular pathogenesis of American Foulbrood: how Paenibacillus larvae kills honey bee larvae

American Foulbrood caused by Paenibacillus larvae is one of the unsolved health problems honey bee colonies are suffering from. In the recent past, considerable progress has been achieved in understanding molecular details of P. larvae infections of honey bee larvae. This was facilitated by the development of molecular tools for manipulating P. larvae and by the availability of complete genome sequences of different P. larvae genotypes. We here report on several peptides and proteins that have recently been identified, biochemically analyzed, and proposed to act as virulence factors of P. larvae. For some of them, experimental proof for their role as virulence factor has been provided allowing presenting a preliminary model for the molecular pathogenesis of American Foulbrood.