Understanding plant-microbe interactions

With a relentless passion for plants, a strong desire to secure the world’s food resources and numerous papers and awards under his belt, Dr Jonathan Plett from Western Sydney University is one of Australia’s most promising scientists.

Last year, Plett’s research and engagement on the relationships between plants and the fungi in soils saw him receive the much-coveted 2016 NSW Young Tall Poppy Science Award. Issued by the Australian Institute of Policy and Science, the Young Tall Poppy Science Awards recognise promising young scientists who achieve scientific excellence and demonstrate a commitment to sharing their passion and knowledge.

Plett is one of the many interesting speakers at this year’s ComBio conference, being held at the Adelaide Convention Centre from 2–5 October. We interviewed him to learn more about his past, present and future in the world of plants. 

Lab+Life Scientist: How did you become interested in plant science?

Jonathan Plett: The love of research runs in the family — my father and brother are both engineers, my mother was in the field of Biblical studies and my cousin’s in English literature. I, on the other hand, loved plants. From a young age, how plants grow and flower and flourish has fascinated me.  

My father had a huge veggie garden that he would dedicate hours to every week, from early spring to the final frost. As a young child, he’d let me look through seed catalogues with him and let me pick out a few seeds that I could plant and grow myself. This began a lifelong passion for growing plants. When I was 10, an English couple moved in next door and proceeded to turn their entire property into a huge flower garden. When they saw how enthralled I was with their achievement, they offered to teach me how to grow flowers. So I roped my father into the deal and, through their tutelage and a lot of sage advice from my father, I planted my first flower garden and spent the next five years learning how to grow a whole range of perennial flowering plants, bushes and vines. I have never looked back — every house I have lived in since has always had at least a corner of the yard or patio dedicated to growing plants, and this has naturally extended now into my work.

So I suppose that the possibility of being able to turn my passion for plants into a career was what drew me into studying science and eventually into a career in research.

LLS: What’s your lab’s current research focus?

JP: Currently my group is focused on trying to understand how the plant immune system works. Specifically, we are trying to understand how the plant is able to filter/identify/interpret chemical and protein signals from soil-borne microorganisms (microbes) to determine if a given microbe will be beneficial or detrimental to plant health. We hope to use this information to breed new crops or select new stock for forestry plantations that are better able to withstand disease-causing microbes, while fostering relationships with other microbes that can benefit their health and productivity.

LLS: Tell us about your ‘eureka’ moments.

JP: One of the most exciting eureka moments in our lab was a couple of years ago. We had spent a number of years studying how plant immune responses were controlled during the interaction between plants and either disease-causing or beneficial microbes.  

We found that if certain immune responses were triggered they would kill off the microbe, regardless of whether that microbe was beneficial or detrimental to plant health. This led us to hypothesise that crop breeding programs aimed at delivering disease-resistant cultivars may inadvertently also be breeding for reduced association with symbiotic beneficial microbes — if the breeding process led to the selection of new varieties that made use of these particular detrimental immune responses. Together with the Department of Primary Industries and Pulse Breeding Australia, we tested this hypothesis and found that it was true — in certain varieties of chickpea, the disease resistance that had been bred into the variety also reduced nutrients that the plant normally sourced from symbiosis with beneficial soil microbes. This discovery has led to a continued project with the Department of Primary Industries and Pulse Breeding Australia to help with selection of new legume varieties that are disease resistant without losing the ability to form beneficial symbiotic relationships with soil microbes.

LLS: What are you going to talk about at ComBio?

JP: I will be talking about the work that led up to the eureka moment. 

The abstract, if you’d like, is that in forest and agricultural ecosystems, plant roots are valuable real estate where beneficial and pathogenic microbes are competing for the chance to colonise, and exploit, plant nutritional resources. Our understanding of the inter-kingdom communication that occurs between host and microbial cells to favour the formation of these interactions is still developing. 

The objective of my research is to ‘listen in’ on these molecular dialogues and to understand how plants are able to distinguish between beneficial and detrimental associations with the plethora of microbes found within the rhizosphere. I will focus my discussion on recent advances in our understanding of how the plant hosts are able to deploy different types of defences, depending upon the microbes present in the soil, and how microbes attempt to manipulate these defence responses. I will conclude with the ramifications this recent work has on how we approach plant breeding and plant varietal selection for agriculture and forestry applications.

LLS: What are some of the biggest challenges in researching plants?

JP: I actually see that there are more benefits to doing research in plants than there are challenges. If I were to pick one, however, it would be the speed with which one can work with plants. People who work with bacteria or yeast as research models have a generation time on the order of minutes to hours. When you work with plants, this generation time is on the order of months to, if you work with trees, decades. So if you want to manipulate the genetics of certain plant models, it can be extremely challenging and time-consuming. However, new technologies and methodologies are starting to change this. So, thankfully, the future may hold new ways of working with recalcitrant plant models that are important in both managed and natural environments.

LLS: Can you highlight some of the benefits of the latest technological advancements?

JP: Like any science, technological advances in recent years have helped us immensely. Some of the biggest aids to my work have been the availability of fully annotated plant genomes to study the genetics of my plants of interest (eg, chickpea, eucalypts, etc). Advances in the area of gene and RNA sequencing have also brought down the costs of doing genetic profiling of plants, making larger scale and more meaningful studies of how plants interact with microbes more feasible.  

LLS: What about gene editing?

JP: There are huge opportunities to use new technological advances such as gene editing to develop new crops that will meet future food needs. With genome editing, we can breed crops that are more disease tolerant, that are nutrient efficient and that produce more bountiful crops at a faster pace and in a more targeted manner than with traditional breeding. The biggest challenge, as always, is public perception of gene editing and public acceptance of the safety of such technology.  

LLS: What are some of the areas where progress hasn’t happened as fast you’d have liked?

JP: I would say that one of the areas that makes me most frustrated is in how we, as a scientific community, have not taken/made opportunities to communicate what we do with the general public. This has led to some of the problems I mentioned earlier, such as people questioning the safety of genetically modified organisms — it has led to questions of whether research is important or if it even affects their daily life. Lack of communication of our work with governing bodies has led to cutbacks in essential basic science that will give the breakthroughs that we need in the coming years. I cannot count the number of times I have heard non-scientists ask “why should I care about research?” — and that makes me incredibly sad.

I would hope that our generation of scientists, and the new generation of researchers that are currently coming through their schooling, would realise the importance of science communication outside of the normal academic circles. I hope that people would make use of social media, talk with journalists and get people excited about science. I would hope that within my lifetime, I will no longer hear questions on whether science and research support society, but rather how society can further support research.

Image supplied by Dr Jonathan Plett.