Brady Welsh

Mr Brady Welsh

Higher Degree by Research Candidate

PhD Candidate

School of Biological Sciences

Faculty of Sciences, Engineering and Technology

I am currently a PhD candidate at the University of Adelaide investigating the impact of fungicides on the phyllosphere microbiome of Vitis vinifera (grapevines) and the downstream consequences that this has on the sensory profile of wine. My project is a new collaboration between the School of Biological Sciences and the School of Agriculture, Food & Wine under the supervision of Dr. Stephen Kidd, Dr. Raphael Eisenhofer and A/Prof Susan Bastian.

The Impact of Fungicides on the Phyllosphere Microbiome of Grapevines

Diseases which effect grapevines used for winemaking can cause tremendous burden on the wine industry, and as such, an array of chemical fungicides are used to prevent and treat instances of disease. Although viticulturists have used broad-spectrum fungicides for hundreds of years, the discovery of the vine’s microbiome highlights the risk of potential off-target and downstream effects caused by these disease treatments. Using both quantitative and qualitative techniques such as quantitative PCR and rRNA gene amplicon sequencing techniques, respectively, we aim to investigate how various fungicide conditions shape the grapevine microbiome over time via off-target interactions with the non-pathogenic microbial communities. With the interconnected nature of the grapevine microbiome and its role in plant health and the fermentation process, identifying these potential off-target effects is key to improving the health and yield of grapevine plants as well as ensuring the consistent production of high quality wines.


Potted grapevines on bench in glasshouse. Photo Credit: Brady Welsh


inoculated wines vs wild winesThe Viable Phyllosphere Microbiome

One of the most significant limitations to current microbiome analysis techniques is the inability to differentiate between DNA that originated from viable microbial sources, and DNA from non-living sources, known as relic DNA. Relic DNA makes up all DNA from sources such as dead cells, compromised cells or the environment (eDNA) and can be amplified and sequenced alongside target DNA, leading to a potential for false positives within results.  As such results obtained using these methods at their current capacity must be regarded with suspicion as to which microorganisms were truly associated with their respective host. To combat these limitations within phyllosphere microbiome research, we are developing a sampling protocol which utilises viability selection. With this viability sampling protocol, greater characterisation of the phyllosphere microbiome can be achieved and more accurate conclusions made on factors that impact the structure of the plant microbiome.

We have also discussed how this protocol can be utilised for microbial monitoring in vineyards which focus on the production of 'wild wines', which are fermented using the inhabitants of the grapevine microbiome. For these wines to be successful, specific micro-biodiversities must be maintained to produce wines with the desired sensory characteristics. As such microbial monitoring is required to ensure the vineyards microbiome is properly maintained, and with the utilisation of viability selection, this can be done with greater accuracy and reduced risk of misleading results. 



  • Journals

    Year Citation
    - Welsh, B. L., Eisenhofer, R., Bastian, S. E. P., & Kidd, S. P. (n.d.). Monitoring the viable grapevine microbiome to enhance the quality of wild wines. Microbiology Australia, 44(1), 13-17.
  • Conference Items

    Year Citation
    2022 Welsh, B. L., Eisenhofer, R., Bastian, S. E. P., & Kidd, S. P. (2022). The Impact of Fungicides on the Phyllosphere Microbiome of Grapevines. Poster session presented at the meeting of the 18th Australian Wine Industry Technical Conference. Adelaide, Australia.
  • Theses

    Year Citation
    2019 Welsh, B. L. (2019). Oral Campylobacter Spp. and Periodontal Disease: A Metagenomic Approach. (Undergraduate Dissertation, The University of Adelaide).
  • Memberships

    Date Role Membership Country
    2021 - 2023 Member Royal Society of South Australia (RSSA) Australia
    2020 - ongoing Member Golden Key International Honours Society Australia
  • Event Participation

    Date Event Name Event Type Institution Country
    2022 - 2022 SBS Research Symposium 2022 Symposium The University of Adelaide Australia
    2022 - 2022 18th Australian Wine Industry Technical Conference Conference AWITC Australia
    2021 - 2022 SBS Research Symposium 2021 Symposium The University of Adelaide Australia
    2021 - 2021 MicroSeq 2021 Conference Australian Society of Microbiology Australia
  • Presentation

    Date Topic Presented at Institution Country
    2022 - 2022 'In The Wine Light' 18th AWITC AWITC Australia
    2021 - 2021 Vines, Wines and Microbiomes: How Fungicides Shape The Grapevine Microbiome JAMS Adelaide Sponsored by FAME JAMS Adelaide Australia
    2021 - 2021 Vines, Wines and Microbiomes: How Fungicides Shape The Grapevine Microbiome MicroSeq 2021 Australian Society of Microbiology Australia
  • Position: PhD Candidate
  • Email:
  • Campus: North Terrace
  • Building: Molecular Life Sciences, floor 5
  • Org Unit: School of Biological Sciences

Connect With Me
External Profiles

Other Links