In the 1960s, the green revolution transformed agriculture. The development of dwarf cereal varieties and the implementation of modernized practices led to increased yields, saving millions from starvation, and resulting in a Nobel peace prize in 1970.
These days, we are longing for a second green revolution. More and more arable land is lost due to many factors, while the world’s population still increases. Practices implemented during the first green revolution, such as fertilizer application, will have to be replaced by new strategies; fossil phosphorous deposits, for example, will be depleted soon. High hopes are currently placed in supplying plants with beneficial microbial partners: it was shown that several fungi and bacteria are able to increase biotic and abiotic stress tolerance, as well as crop yield. However, attempts to add these ‘biological fertilizers’ to crops in agricultural settings to increase yield showed mixed results. These strategies demand an increase of our understanding of plant-microbe interactions in order to be able to supply the appropriate beneficial partners to crops growing in a distinct environment and thus to achieve a reliable increase in yield.

Conceptually, it is well known that plants are able to sense microbes in their environment, and to respond to their presence by modulating their metabolism. Past decades of research revealed that the presence and amounts of metabolites produced by plants can influence the growth of microbes. However, exactly how plants shape their interaction with microbes remains unknown.



This principal component analysis shows exudation profiles of three plant species (blue, green, yellow). The distinct clustering of the profiles highlights that the species exude distinct compounds.



On the left side of the root, plant transporters involved in exudation are displayed with their substrate. Absence of these transporters often leads to altered presence of microorganisms. On the right side of the root, substrate classes are presented for which no transporters involved in exudation have been reported yet.

We focus on elucidating how roots interact with different kinds of microbes by altering root exudation. Different approaches were designed to address this question.

A better understanding of the mechanisms of plant-microbe interactions is a first step towards the production of crops with an increased stress resistance in their natural environment. The discovery of the molecular basis of plant-microbe interactions will allow to select beneficial partners for a specific crop growing in a specific environment, and to successfully integrate beneficial partners into the existing microbiome associated with the crop. Further, we aim to suppress the growth of pathogens by limiting its resources or preventing its proliferation in the existing community. In the future, engineering of plant-microbe interactions will allow us to reduce agricultural inputs such as fossilized fertilizers, keeping crop yield constant or even increasing it.

Our current work is supported by a Swiss National Science Foundation (SNSF) PRIMA fellowship.