VIB research sheds new light on the defense mechanisms of plants

10 October 2016
When plants are damaged, they face significant dangers including the loss of nutrients from and the entry of microbes into the plant. As a result, plants have evolved sophisticated defense mechanisms. Unlike animals, each plant cell has the ability to activate protective responses to heal damaged tissue and prevent microbe infections. New insights into the subcellular workings of these defense mechanisms have been presented by the teams of Prof. Jenny Russinova (VIB-Ghent University) and Prof. Daniel Scherer de Moura (University of São Paulo, Brazil), sharing the PhD student Fausto Andres Ortiz-Morea. The findings could help scientists in modulating the behavior of food production plants, so that they are better protected against environmental factors.

The ability of plants to ‘sense’ danger is based on the recognition of certain molecular patterns by a large arsenal of receptors located on the membranes of plant cells. These receptors can be triggered by both microbe-associated and damage-associated patterns. For example, microbes are identified through the molecular patterns of flagellin or chitin, while injuries can be signaled by endogenous peptides. Once activated, the receptors trigger an immune response and transfer the danger signal to the rest of the plant.

A closer look at the plant’s alarm system
Recently, an increasing number of signaling peptides have been discovered that play an active role in the cell-to-cell communication networks of plants. However, the subcellular dynamics of these molecules and their involvement in immune responses have remained unclear. Dr. Russinova’s team and colleagues have now realized the first in vivo visualizations of these subcellular dynamics. They have used the plant model of Arabidopsis thaliana to investigate the relationships between plant defense and the subcellular behavior of the plant’s endogenous peptide AtPep1.

Fausto Andres Ortiz-Morea: “Our research shows that AtPep1 is recognized very quickly at the cell surface by its receptors, which activates the plant’s defense responses. After that, the peptide is engulfed by the cell – a process called endocytosis – as a complex (AtPep1-receptor). This allows the complex to be broken down, which desensitizes the AtPep1 stimulus. We also provide solid proof that this endocytosis is mediated by a special protein called clathrin, the involvement of which is essential to guarantee plant defense responses.”

Promising results
With this research, the scientists have established a biological model system and developed novel technical approaches that enable the further study of plant endomembrane trafficking and its role in plant immunity signaling.

Jenny Russinova: “This could help scientists generate strategies to modulate plant behavior in favor of societal needs by protecting edible plants against microbes and damage. Our work also opens new, interesting avenues for cell biology research in the field of plant innate immunity.”

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Publication
Danger-associated peptide signaling in Arabidopsis requires clathrin, PNAS 2016
DOI: 10.1073/pnas.1605588113


Jenny Russinova (VIB-UGent)
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