This InterView with Angela Sessitsch, head of the Competence Unit at the Austrian Institute of Technology, was conducted by Bruna Gonçalves Coutinho, a post-doc at the University of Washington. If you are interested in completing your own InterView, please contact Interactions Editor-in-Chief Dennis Halterman.
Bruna Gonçalves Coutinho (BGC): You have been studying plant–bacteria interactions for a long time now. Why did you choose this as your research topic? Of your many contributions to the field, which is the one you are most proud of?
Angela Sessitsch (AS): I did my PhD on Rhizobium–legume interactions and was fascinated with how microorganisms can contribute tremendously to plant nutrition. At that time, I also got to know Johanna Döbereiner from Brazil, and she indeed had a vision on microbial contributions to agriculture. For example, she found that nitrogen fixation by endophytes in sugarcane was a great economic contribution to bioethanol production in Brazil. Thereby, endophytes contributed to a great bioethanol program in that country. At that time, I got more and more interested in plant–microbe interactions beyond Rhizobium.
I am not sure what has been the greatest contribution of my career, but already about 15 years ago, we showed that endophytes are active inside the plant and that microbial (endophytic) communities respond to plant physiology and plant stress. This was at a time when even plant microbiologists did not believe in the existence or importance of bacterial endophytes. We also did the first metagenomic analysis of root endophytes, which was not only an advance to our understanding of endophyte functioning but also a tremendous technical challenge, as it was before the use of next-generation sequencing and we had to remove plant-derived DNA as efficiently as possible. More recently, my team discovered a way to integrate bacterial inoculant strains into seeds, which has opened a completely novel way to modulate microbiomes and has great value for commercial applications.
BGC: We have been seeing an explosion of research on bioinoculants. Several companies and academic labs are working on the discovery and formulation of microorganisms that can replace or act together with chemical fertilizers to boost crop production. However, this is not a new field of research. What do you think has changed in the field that has allowed for this renewed interest in the subject?
AS: Well, it is not new, but it was a niche market, except for Rhizobium inoculants. A few years ago, plant scientists became aware that plants—like humans and other animals—host a diverse microbiota, which is crucial for health, nutrition, and stress resilience. This made a huge difference, as before, plant scientists and plant breeders completely ignored the existence of plant microbiota. This increasing awareness of the existence and the potential of microorganisms, as well as the fact that many chemicals are being taken away from the market, has led to big expectations from the plant microbiome. Further drivers are climate change and massive yield losses due to drought, which may be alleviated by microorganisms but not by chemicals, as well as demographic development, which requires yield increases.
BGC: Your lab and several others have used metagenomics to contribute to a broadened culture-independent view of plant microbiome and their activities. How can the scientific community leverage the power of metagenomics to develop targeted microbial-based products?
AS: This is an interesting and challenging question. I believe that metagenomics allows us to obtain structural information on the communities associated with the plant and that learning the ecology of microbiomes may lead to a better understanding of which strains can better establish in a certain habitat or in association with a specific plant. Metagenomics may lead us in isolation campaigns in order to obtain better inoculant strains or reveal markers indicating beneficial interactions.
BGC: What are the biggest challenges we face in order to move this technology forward?
AS: There are a couple of challenges. For instance, we all agree that field success has to improve. There are a couple of issues to consider in that aspect, such as the development of suitable formulations or application approaches. But the ecology and competitive ability of strains have to be considered, as well. Generally, we have to move from trial and error to discovery- and application-based understanding.
BGC: Microbial-based products are yet to be widely adopted in agriculture, but preliminary research suggests a clear potential for application globally. One challenge facing the industry is avoiding negative public perceptions, such as those previously experienced by biotech crop industries. How do you think scientists can help in this aspect?
AS: Communication is an important aspect. The question is, who is responsible for it and who is best suited to do it? Companies, in their own interest, should be active in communication with the public sector to avoid negative public perception. It will also be important to involve the academic sector and to provide resources to allow scientists to be involved in stakeholder engagement. Ideally, specialized staff should be hired for communication tasks, and they should involve scientists, as well as other stakeholders, in a dialogue.
