Nationality Finnish
Year of selection2016
InstitutionThe University of York
CountryUnited Kingdom
RiskEnvironmental risks

Type of support

Post-Doctoral Fellowship

Granted amount

130 000 €


2 years

Plants' first line of defence against invading pathogens is their microbiome. Much like humans and animals, plants are hosts to a myriad of micro-organisms with whom they live in symbiosis. Inhabiting their leaves and roots, these microbial communities provide plants with essential services, including fending off diseases. It is currently estimated that 10 to 20% of global food production is lost to plant diseases. Facing increasing demand in food production due to population growth, mitigating these effects will be a critical step for maximizing yields obtained from the current agricultural systems. Focusing on the microbial communities living on the roots, Dr. Lauri Mikonranta is studying the complex dynamics that govern the interactions between host, pathogen and microbiome. Specifically, the researcher is investigating the unclear role of environmental change and bacterial evolution on the outcome of these interactions, namely the plant's health. By providing a better understanding of the resistance of bacterial communities to invading pathogens, his findings aim to contribute to the development of novel and environmentally friendly bacterial-based strategies to viably replace or supplement ineffective and toxic agro-chemicals.

Recent research shows that due to fierce resource competition and high niche overlap, the diverse variety of microbes living in the roots contribute to preventing pathogen invasion. "This is because roots harbour thousands of different species of microbes that compete with invading pathogens", Dr. Lauri Mikonranta explains."Indeed, the microbiome and the pathogens have high number of interacting species and there's not enough resources and space for all of them." "In this sense, diversity plays an important role on invasion resistance", the researcher continues. "But things are more complex than that. The relationship between diversity and invasion resistance is not linear. Other factors come into play, like changes in temperature, nutrient availability, pH balance of the soil, or rapid changes in the characteristics of the species in response to each other." Indeed, environmental conditions and bacterial evolution are likely to change the power relationship by strengthening some while weakening others. To be able to reliably predict pathogen invasion success, scientists need to know more about how bacterial communities and pathogens react to these elements.

Boosting the plant's natural defence barrier using bacterial cocktails

"It could be seen as an arms race type of situation where pathogens and resident microbiota coevolve. However, the pathogens have to transmit between hosts through environmental reservoirs and adapt to those circumstances as well", Dr. Lauri Mikonranta summarizes. "Once we have a better understanding of the global framework of power dynamics, we can use this knowledge to our advantage and boost the micriobiome's resistance by developing strategies such as bacterial cocktails for instance". To carry out his project, Dr. Lauri Mikonranta will conduct experiments on laboratory ecosystem models and on the microbiome of tomato plants, which he will submit to the invasion of a devastating soil borne plant pathogen. Looking at how their complex interactions unfold depending on environmental conditions, the team's objective is to develop a simplified model capable of predicting what will likely happen in the wild.

" Relatively simple and environmentally friendly methods might be sufficient to suppress the worst epidemics if the tripartite interactions of environment-pathogen-resident community were understood better", Dr. Lauri Mikonranta stresses. By filling the gap, the researcher's project will significantly contribute to the development of strategies to efficiently and sustainably meet growth in food demand and climate change. Furthermore, Dr. Lauri Mikonranta's findings on eco-evolutionary principles relating to the microbiome of plants could be translated into wider microbiome framework. For instance, his research could have potential implications for human macrobiota and the development of novel probiotics.