An international team led by Wageningen University & Research (WUR) has been awarded an ERC Synergy Grant of 12.1 million euros. Over the next six years, the team will investigate how plants convert external stimuli into specific cellular responses. The researchers will focus on the first minute of signal processing in plant cells, a phase that has been largely unexplored so far.
Plants constantly respond to stimuli around them such as heat, light, hormones, nutrients and pathogens. Yet scientists know very little about exactly what happens inside a cell after it receives a signal. Dolf Weijers, Professor of Biochemistry at Wageningen University & Research (WUR), will investigate these early communication processes with colleagues from Ghent, Zurich and Madrid. The researchers aim to identify which receptors in the cell detect the signals and which biochemical processes follow.
How plant cells combine simultaneous signals
The team will investigate sixty different signals, ranging from nutrients such as nitrate and phosphate to pH levels and signals from pathogens. Since plants in nature rarely encounter just one stimulus at a time, the researchers will also study how plant cells combine different signals. Do they reinforce each other, counteract one another, or trigger an entirely different response when combined?
Until now, researchers have mainly focused on slower responses that occur minutes or even hours after a stimulus, such as the activation or deactivation of genes. Yet it is precisely in those first few seconds that important changes can take place, offering valuable insights into plants and how their cells communicate. "Actually, it stands to reason that those initial steps take place within seconds," says Weijers. "After all, all molecules involved in a signal are already present in the cell. They simply need to bind to one another or change shape. Yet we have never studied these processes in this way before."
Measuring plant cells in a microfluidic chip
To capture these early responses, the researchers use a microfluidic chip: a plastic plate measuring roughly five by five centimetres. Inside the chip, cultured plant cells mix with a liquid containing the signal to be investigated within milliseconds. The researchers then freeze the cells after, for example, one, ten or sixty seconds. Using mass spectrometry, they then measure changes in the cell's proteins, including phosphorylation: a process that switches proteins on or off and thereby influences signalling pathways.
"A whole new world is opening up to us. Not only because the technology was lacking, but also because we did not fully realise how much happens in those first seconds."
- Dolf Weijers
- Project manager
Initial experiments with flagellin, a component of bacteria, demonstrate just how quickly these processes unfold. Some changes in the signalling pathway lasted only five seconds. With conventional sampling times, for example fifteen minutes after a stimulus, these early responses would go undetected. The results also show that cells strictly regulate not only the activation of proteins, but their deactivation too. Weijers adds: "This brings us closer to understanding how a cell actually perceives its environment. A whole new world is opening up to us, one that we simply could not see before. Not only because the technology was lacking, but also because we did not fully realise how much happens in those first seconds."
Four research groups, one joint approach
The project brings together expertise from four research groups: WUR, Ghent University, the University of Zurich and the Complutense University of Madrid. The teams combine knowledge of signal biochemistry, cell biology, protein analysis and computational modelling. Together, they will analyse around 9,000 samples and develop models to predict how plant cells respond to different signals.
About the ERC Synergy Grant
The ERC Synergy Grant is the largest grant awarded by the European Research Council (ERC). This prestigious funding programme supports teams of two to four principal investigators working together on groundbreaking research. It aims to address complex scientific questions that can only be answered through collaboration between experts with complementary expertise.
