Plants must constantly integrate information on the availability of water and nutrients or about the presence of pathogens to produce fruits and seeds for reproduction, heavily used for human consumption. Given the increasing threat of droughts and the requirements of sustainable plant protection it is important to better understand the molecular mechanisms behind the information processing of plants. So far, different plant hormones were known to trigger molecular signaling pathways that result in developmental transitions like fruit ripening or drought response. While the signaling pathways are well studied, it remained enigmatic how the information exchange between them exactly works.
Hundreds of new information exchange points identified
A team at the Institute of Network Biology at Helmholtz Zentrum München with the participation of LMU biologists charted the molecular protein network of plants by experimentally testing more than 17 million protein pairs for physical interactions using a next-gen robotics pipeline combined with latest bioinformatics methods. The network of more than 2,000 observed protein interactions was analyzed using bioinformatic mathematical approaches form statistics and graph theory to find the signaling pathways and potential information exchange points. This way the researchers identified hundreds of these points which were not known before.
Most proteins function in multiple signaling pathways
Next, by using genetic tests, they could show that all tested information exchange points between proteins that were thought to function in single signaling pathways, in fact, organize the communication between different pathways. "This was one of the most striking new insights from this study: Most proteins function in multiple signaling pathways. Moreover, in contrast to single-gene analyses, our results revealed the high degree in which different pathways are physically and functionally intertwined. We believe that this is a fundamental principle and we need to pay more attention to it", says Dr. Melina Altmann, first-author of the study.
Prof. Pascal Falter-Braun, Director at the Institute of Network Biology and professor at LMU adds: "This insight might open new strategies for biotechnological development or breeding of plants to address the challenges of climate change in farming. We might be able to redirect the information in crops such that the plants require less fertilizer or pesticides or are more resistant against droughts."
Funding and collaboration
The finding builds on long-term research at the Institute of Network Biology on understanding molecular networks in plants and humans. The project was funded by the DFG via SFB924 "Molecular mechanisms regulating yield and yield stability in plants" and by an ERC consolidator grant awarded to Prof. Pascal Falter-Braun. For this study, the group collaborated with groups from the School of Life Science at the Technical University of Munich (TUM), colleagues from the Department of Environmental Sciences at the Helmholtz Zentrum München, and the University of Warwick, UK.