Professor Peter Solomon

BAppSc(Hons), PhD
Lab Leader, Wheat Biosecurity
College of Science

Areas of expertise

  • Plant Pathology 060704
  • Post Harvest Horticultural Technologies (Incl. Transportation And Storage) 070605
  • Plant Physiology 060705
  • Plant Cell And Molecular Biology 060702
  • Proteomics And Intermolecular Interactions (Excl. Medical Proteomics) 060109
  • Microbial Genetics 060503
  • Analytical Biochemistry 060101
  • Mycology 060505
  • Plant Biology 0607
  • Oenology And Viticulture 070604
  • Population, Ecological And Evolutionary Genetics 060411
  • Biochemistry And Cell Biology 0601
  • Microbiology 0605

Research interests

 

Fungal diseases of wheat threaten global food security

Fungal diseases are the cause of millions of tonnes in yield losses each on farms around the world. This is serious issue not only in terms of financial losses, but also when considering food security and stability. As an example, the Table below outlines losses on Australian wheat farms to disease. The top 4 diseases in terms of losses are caused by fungal pathogens (based on 2008 prices). Using today's wheat prices, the losses from fungi in Australia exceed $1 billion dollars, and that is using effective control measures; without these losses would exceed $5 billion dollars. Thus there are many good reasons to better understand how these pathogens cause disease!

Wheat Disease
$/ha AUD
Total losses
($M 
AUD)
yellow spot 17.82 212
stripe rust 10.62 127
septoria nodorum blotch 9.07 108
crown rot 6.63 79
Pratylenchus neglectus 6.13 73
Total losses from others 26.37 314
Total present loss 76.94 913

                            

How do these pathgoens cause disease?

Our laboratory focuses on two significant pathogens of wheat. Stagonospora nodorum is a fungus that causes leaf and glume blotch disease on wheat (septoria nodorum blotch). This disease causes greater than $100 million dollars in yield losses per annum in Australia alone and has been recently ranked as the third most important disease of wheat in this country. Traditional breeding methods for disease controls have only been partially successful at best and new and innovative anti-fungal strategies are required to prevent disease and secure Australian and global wheat supplies in the future.

Not only is S. nodorum a threat to global food security, its also extremely interesting and versatile to work with! S. nodorum can be cultured in the lab and is amenable to many common genetic techniques such as targeted gene disruption and gene overexpression. The genome sequence has been completed and extensive proteomics and metabolomics resources have been developed making S. nodorum a perfect model pathogen to better understand plant-pathogen interactions. 



                       


The second wheat pathogen we study in the lab is Zymoseptoria triticiZ. tritici is the most important pathogen of wheat in Europe, the region that produces one-fifth of the world's wheat supply. Zymospetoria tritici is a fungal pathogen of wheat related to Stagonospora nodorum, and is the causal agent of the most important wheat disease in Europe (septoria tritici blotch). This single disease alone is responsible for greater than $1 billion dollars in losses each year. The disease is particualrly problematic in that natural sources of resistance are difficult to source and the pathogen is very adept at rapidly evolving fungicide resistance. 

Interestingly, the disease isn't currently a major problem in Australia. There are many postualted reasons for this including the possibility that European isolates of the pathogen have evolved to be more aggressive. Fortuantely, Australian quaratine has prevented these isolates from entering Australia however the pathogen remains a serious biosecurity risk.

Our lab is studying all aspects of the above diseases with a focus implementing this improved undersantding to facilitate new and novel disease management strategies. 


Fungi synthesize an amazing range of novel and active compounds!

Another research area in the lab is focused on understadning fungal secondary metabolism and idenitfying novel metabolites. Fungal secondary metabolites are amongst the biologically active compunds on the earth and are part of our dailey lives, for good or bad ... . For example, its almost impossible to count how many lives penicillin has saved. More recently, statin-based drugs have an enourmous impact of many peoples lives in terms of cholesterol control. However, not all these compounds are benenfical. Many fungi produce compounds that are lethal. Aflatoxin is the worst carcinogenic toxin produced in nature whilst a variety of palant pathogenic fungi produce mycotoxins that render the plant useless to eat (for humans or animals). And who can forget death cap mushrooms!

Our lab has multiple projects available from everything including determining the relevance of these secondary metabolite compounds on plant disease to isolating new compounds as novel bioactives.

Researcher's projects

 

Studying pathogen proteins that cause disease

We have recently shown that S. nodorum produces proteins (knownn as effectors) that have a significant role in causing disease. These proteins appear to be secreted by the fungus during the very early stages of infection and internalised within the wheat host cells. Inside the host cells, the proteins then interact with the wheat host via a gene-for-gene interaction by an as yet undetermined undergo a  with corresponding host genes which results in disease. The molecular basis of this interaction is unknown. Studies to date with collaborators have identified three host specific toxins, ToxA, Tox1 and Tox3. 

Multiple projects are available in the following areas to study these effector proteins further (skills gained in these projects are shown in brackets);

  1. How does wheat respond to the effector protein exposure at the transcript level? (RNA isolation, RNA sequencing, bioinformatics)
  2. How are these effector proteins regulated? The genes encoding these effector proteins are only expressed either during infection or under very specific in vitro conditions. Why? (Molecular biology, promoter analysis using GFP fusions, genetic modification techniques)
  3. Localisation of the effector proteins during infection. Where do the effector proteins go during infection? This can be monitored using confocal microscopy and fluorescence. (confocal microscopy, mircoscopy sample preparation techniques, molecualr biology)
  4. Do the pathogen effector proteins bind to wheat proteins during infection? (yeast 2-hybrid analysis, co-immunoprecipitation, molecular biology

Characterising the Zymospetoria tritici - wheat interaction

Zymoseptoria tritici is a fungal pathogen that causes the septoria tritici blotch (STB) disease on wheat. STB is the primary pathogen of wheat in Europe and is responsible for hundreds of millions of dollars in losses each year. STB is also a primary biosecurity threat to the Australian wheat industry. Research is currently underway to understand how the pathogen interacts with wheat and causes disease at the molecular level. Projects available include (skills involved in the project are shown in brackets);

  1. Genome sequencing and comparative genomics of Australian Z. tritici isolates (DNA isolation, genome sequencing, bioinformatics).
  2. Isolating pathogen proteins responsible for disease (protein expression, protein purification, molecular biology)
  3. Determining the proteome/metabolome of the pathogen during infection (proteomics, metabolomics)
Opportunities exist for students at a levels to become involved in this project.

Novel metabolite discovery and characterisation

Fungi are prolific producers of biologically active compounds. Examples of such compounds are penicillin and lovastatin. These compounds are produced in fungi by what is known as secondary metabolite gene clusters. Many fungi contain over 40 of these clusters, with each having the capacity to make multiple novel compounds. However the role of these compounds, or indeed their identity, for the most part remain unknown.

Projects are available in the lab looking at the role of these secondary metabolite compounds in causing disease. Further opportunties also exist to identify these novel metabolites and discover their roles.

 

 

Available student projects

PhD, Honours and Summer Scholarship projects are now available to study a wide range of topics in biosecurity and pathogenesis

Listed below is an example of projects available in the Solomon lab. Please contact Peter to discuss these further or other possibilities (not that the skills gained in the project are shown in brackets after the project) …

Studying pathogen proteins that cause disease

1. How does wheat respond to the effector protein exposure at the transcript level? (RNA isolation, RNA sequencing, bioinformatics)

2. How are these effector proteins regulated? The genes encoding these effector proteins are only expressed either during infection or under very specific in vitro conditions. Why? (Molecular biology, promoter analysis using GFP fusions, genetic modification techniques)

3. Localisation of the effector proteins during infection. Where do the effector proteins go during infection? This can be monitored using confocal microscopy and fluorescence. (confocal microscopy, mircoscopy sample preparation techniques, molecualr biology)

4. Do the pathogen effector proteins bind to wheat proteins during infection? (yeast 2-hybrid analysis, co-immunoprecipitation, molecular biology)


Characterising the Zymoseptoria tritici-wheat interaction

5. Genome sequencing and comparative genomics of Australian Z. tritici isolates (DNA isolation, genome sequencing, bioinformatics).

6. Isolating pathogen proteins responsible for disease (protein expression, protein purification, molecular biology)

7. Determining the proteome/metabolome of the pathogen during infection (proteomics, metabolomics)


Novel metabolite discovery and characterisation

8. Are pathogen secondary metabolites involved in causing disease? If not, what do they do? (genetic modification techniques, basic chemistry, molecular biology, pathogenicity assays)

9. What novel metabolites do fungal secondary metabolites produce? What do they do? (molecular biology, liquid chromatography, mass spectrometry, chemistry)


As the research in the Solomon lab is focussed on the Australia wheat industry, substantial scholarship top-ups are available for PhD and Honours studetns through the Grains Research and Development Corporation. 

Small travel grants are also available within Australia if you are interested in visiting the Solomon lab to discuss PhD options.

 

Publications

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Updated:  19 January 2022 / Responsible Officer:  Director (Research Services Division) / Page Contact:  Researchers