How plants turn into zombies

Scientists from Jena University (Germany) shed light on the molecular reasons for a bacterial plant disease: In the latest issue of the science journal Trends in Plant Science, the researchers explain how phytoplasmas destroy the life cycle of plants and inflict a 'zombie' existence on them.

"The insects transmit bacteria, so-called phytoplasmas, which destroy the life cycle of the plants," says Günter Theißen. Instead of blossoming, the afflicted specimens only form vestigial leaf structures and thus prevent sexual reproduction. "These plants become the living dead," the geneticist points out. "Eventually they only serve the spread of the bacteria." Therefore, the scientists also call these plants 'zombies'.

Theißen and his Jena team have just succeeded in making a significant contribution to understanding the molecular-biological reasons for this phenomenon. In the latest issue of the science journal Trends in Plant Science the researchers explain how the parasites interfere with the development of plants in such a disastrous manner and inflict a 'zombie' existence on them.

One of the main culprits is a bacterial protein called SAP54. On basis of modelling studies, the Jena scientists were able to show that SAP54 imitates the structure of certain MADS-domain-proteins in the infected plants that perfectly that they connect with SAP54 instead of their own proteins. This eventually leads to the degradation of the MADS-domain-proteins, so that they can no longer fulfil their normal function within the regulatory complexes of the blossom development. "This prevents the formation of petals and flower organs," Rümpler explains.