The not so simple interactions associated with PR-1 proteins and Septoria nodorum blotch in wheat

Lisa Rothmann
OPP Blog and Social Media Editor

Dr. Peter Solomon @petersolomon99, from The Australian National University (Canberra), is the professor leading research at the Solomon Lab, focusing on wheat biosecurity. Peter delivered a talk on, How the study of necrotrophic effectors advanced our understanding of the enigmatic PR-1 protein on the 20th of April at the #OPPVirtualSeminars.

OPPVirtualSeminar Experience: Question and Response

OPP: How did you find your experience presenting for the OPP Virtual Seminar? Have you done something similar in the past?

No, I haven’t done anything like this in the past. As an experience, I found it particularly interesting. I am comfortable giving talks to both small and large crowds and have done so at conferences around the world. One aspect of giving a face-to-face seminar is that you can gauge the reception of the presentation by observing the audience - and moderate “on the run” accordingly. Of course, this is something you can’t do in a virtual seminar so I must admit to finding that a little challenging for the initial part of the talk.

Any advice to future virtual seminar presenters?

Basically, be mindful of the point above - whilst there is no visible audience in front of you - they are listening!

Research Orientated: Question and Response

You have been working on/with Parastagonospora nodorum for ~20 years, it seems a complex pathosystem. Not many people have the privilege of gaining such a wonderful knowledge and experience base. How have changes in science and research affected your approach to asking and answering questions associated with Septoria nodorum blotch? And how do you keep motivated through the challenges?

My motivation comes from wanting to understand the interaction (or indeed interplay) between this pathogen and the host. Whilst we initially thought this was going to be a very simple system, it has proven to have complex intricacies which have provided a pleasant challenge for dissecting it further. This was enabled through the sequencing of the P. nodorum genome, which at the time was a costly affair but a worthy cause indeed. Whilst such new approaches like genome sequencing won’t necessarily help in dissecting the biochemistry presented, sequencing plays a pivotal role in answering important questions regarding the origin and evolution of such important proteins.

What was one of your biggest “surprises” or unexpected findings considering the Tox3 x PR1 (Snn3, dominant susceptible host) interactions or lack of interactions?

The biggest surprise to me was that the interaction does actually play a significant role in facilitating disease. I was always under the impression that although I was under no doubt that these proteins interacted, I thought that the reasons were perhaps historical. However, this isn’t so and that we have demonstrated that a strain of P. nodorum lacking Tox3 showed significantly reduced disease on wheat lines lacking Snn3 - meaning that the interaction of the protein with PR1 is consequential to the outcome of the interaction.

What is one of the most challenging components of your laboratory work? And how do you resolve this?

As we are getting more towards the “pointy end” of understanding this protein interaction, it is without a doubt that the greatest challenge we face in dissecting this system further is the complexity and genetic intractability of the host. Wheat harbours a very complex hexaploid genome meaning that multiple copies of genes exist derived from its ancestors. We have now (somewhat belatedly) realised this and have moved to try and advance our understanding of this interaction in the Arabidopsis thaliana model system.

Would the manipulation of the responses driving host selective toxins present an opportunity of disease management in potential breeding programs? If so, how? And with the current focus on defining what is “genetically modified” how does this impact the potential use?

Because of the pathogen’s reliance on exploiting dominant genes within the host, this disease is relatively manageable by removing the susceptibility genes through conventional breeding (or indeed CRISPR if required). The findings relating to PR1 are important as they provide much-needed information about an important defence protein that is likely to help in the innovation of the disease management approaches in other pathosystems. E.g. Can we overexpress the CAPE1 peptide under a pathogen-inducible promoter? Whilst a blue-sky thought, it’s important that we continue to think and test, outside of the box as we know it.

Your research team seems like a relatively large and dynamic group working on various components of this study, biochemistry, microbiology and bioinformatics, for example. What are your team management approaches?

Complementary skills within a group are critical. Much of the work I presented was heavily biochemistry focussed but we wouldn’t be where we are without the structural biologists. But other skills are also required, e.g. I am particularly interested in the question of which function for Tox3 came first, PR1 interaction or necrosis-inducing? To answer this will potentially require population genomics expertise. You need to tackle complex problems with multiple approaches - it’s that simple. Much of my group has skills I don’t, I very much believe in finding good people and letting them do what they do best.

Thank you so much Peter for taking the time to speak to me and to share your research on the function of PR1 proteins in Septoria nodorum blotch in wheat. I look forward to seeing your group grow and untangle the intricacies.

You can go and watch Peter’s #OPPvirtualseminar on our official YouTube channel. You are also welcome to interact with us in our Slack Community on our #virtual-seminar channel. By clicking on this link you can request to join Open Plant Pathology on Slack.





Related

comments powered by Disqus