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16 May 2025 | Story André Damons | Photo Supplied
Dr Lisa Rothmann
Dr Lisa Rothmann, a plant disease epidemiologist from the University of the Free State (UFS), has been nominated in the TW Kambule-NSTF Award: Emerging Researcher category for this year’s NSTF-South32 Awards.

Dr Lisa Rothmann, a plant disease epidemiologist from the University of the Free State (UFS) who was nominated in the TW Kambule-NSTF Award: Emerging Researcher category for this year’s NSTF-South32 Awards, says that the nomination is a reminder that service through science matters.

“I am humbled by the nomination. For me, it reflects not just individual recognition, but also the shared effort of the team of postgraduate academics, research assistants, partners, and farmers with whom I've had the privilege to work with. It is affirming to see plant pathology and field-based research recognised in this way; it highlights the consistent (hard) work we do to make a meaningful contribution to agriculture and to serve the grain industry and farmers,” says Dr Rothmann. 

She was nominated by Grain South Africa (Grain SA), with whom she has been working closely since 2018 to contribute research that aligns with the organisation’s mission to strengthen the grain sector. They play a key role in supporting sustainable grain production and farmer development. 

Dr Rothmann, who is one of eight UFS researchers and a research team nominated for the NSTF-South32 Awards – also known as the ‘Science Oscars’ – is nominated for her contribution to interdisciplinary, team-based research to develop practical solutions for plant diseases in order to protect crops and empower communities. 

 

Motivation to keep growing

The Senior Lecturer in the Department of Plant Sciences within the Faculty of Natural and Agricultural Sciences (NAS) says that while she is proud of the work she has done, she sees this recognition as a team effort. Says Dr Rothmann: “It motivates me to keep growing as a researcher, rooted in impact and integrity. I’m not a prolific peer-reviewed publisher; my academic record includes 10 journal articles and one book chapter, but I have written around 50 popular articles – often as a solo author, in collaboration with postgraduates and peers.” 

“These pieces translate plant pathology topics such as the Sclerotinia life cycle, disease surveillance, and management into accessible information for producers and the public. To me, this nomination is a symbol that making a meaningful impact doesn't only come from journal impact factors. This nomination has reminded me that building a career in academia is a relay, not a race, and that lasting impact comes from investing in others.”

As a plant disease epidemiologist, she specialises in field pathology – an area of plant pathology that explores how disease epidemics in crops develop, spread, and can be effectively managed within agricultural systems. Their work centres on understanding and managing Sclerotinia diseases in oilseed and protein crops such as canola, soybean, and sunflower, as well as disease surveillance in key grain crops including dry bean, sorghum, and sunflower.

 

New research

After participating in the US-based National Sclerotinia Initiative in 2017, she was inspired to establish a South African Sclerotinia Research Network with the support of Grain SA, creating a platform for researcher collaboration, farmer engagement, and the development of on-farm management strategies. Over time, explains Dr Rothmann, their research has expanded to include cultivar screening, national disease surveys, fungicide registration trials, and the development of disease-assessment tools. More recently, they have embedded sociological surveys into sorghum disease work to better understand farmers’ knowledge and needs, ensuring that research remains practical and co-created with producers.

According to Dr Rothmann, they have been privileged to work in a space that supports producers and protects crops through applied plant disease management strategies. While high-value crops often attract attention due to export markets, the grain that feed the nation forms the backbone of food security. As part of their new research, Dr Rothman and the research team are currently contributing to the Sorghum Cluster Initiative's pre-breeding programme, where they have screened 160 accessions for diseases to support future cultivar development. 

They are also going to explore how both emerging and commercial farmers will adopt these new cultivars. She is actively seeking collaborators in sociology/psychology or similar fields to better understand farmers’ decision-making. They are developing a plant disease dashboard to map disease occurrences across South Africa – an effort aligned with the Plant Health (Phytosanitary) Act 35 of 2024 to help guide appropriate disease risk categorisation. In the long term, concludes Dr Rothmann, they hope to establish a diagnostic hub for central South Africa in partnership with Agricultural Research Council-Grain Crops to strengthen local disease identification and support producers in real time.

News Archive

Research eradicates bacteria from avocado facility
2017-01-17

 Description: Listeria monocytogenes Tags: Listeria monocytogenes

Listeria monocytogenes as seen under an electron
microscope. The photo was taken with a transmission
electron microscope at the microscopy unit of the UFS.
Bacteriophages (lollipop-like structures) can be seen
next to the bacterial cells.
Photo: Supplied

“The aim of my project was to identify and characterise the contamination problem in an avocado-processing facility and then to find a solution,” said Dr Amy Strydom, postdoctoral fellow in the Department of Microbial Biochemical and Food Biotechnology at the University of the Free State (UFS).

Her PhD, “Control of Listeria monocytogenes in an Avocado-processing Facility”, aimed to identify and characterise the contamination problem in a facility where avocados were processed into guacamole. Dr Strydom completed her MSc in food science in 2009 at Stellenbosch University and this was the catalyst for her starting her PhD in microbiology in 2012 at the UFS. The research was conducted over a period of four years and she graduated in 2016. The research project was funded by the National Research Foundation.

The opportunity to work closely with the food industry further motivated Dr Strydom to conduct her research. The research has made a significant contribution to a food producer (avocado facility) that will sell products that are not contaminated with any pathogens. The public will then buy food that is safe for human consumption.


What is Listeria monocytogenes?

Listeria monocytogenes is a food-borne pathogenic bacterium. When a food product is contaminated with L. monocytogenes, it will not be altered in ways that are obvious to the consumer, such as taste and smell. When ingested, however, it can cause a wide range of illnesses in people with impaired immune systems. “Risk groups include newborn babies, the elderly, and people suffering from diseases that weaken their immune systems,” Dr Strydom said. The processing adjustments based on her findings resulted in decreased numbers of Listeria in the facility.

The bacteria can also survive and grow at refrigeration temperatures, making them dangerous food pathogens, organisms which can cause illnesses [in humans]. Dr Strydom worked closely with the facility and developed an in-house monitoring system by means of which the facility could test their products and the processing environment. She also evaluated bacteriophages as a biological control agent in the processing facility. Bacteriophages are viruses that can only infect specific strains of bacteria. Despite bacteriophage products specifically intended for the use of controlling L. monocytogenes being commercially available in the food industry, Dr Strydom found that only 26% of the L. monocytogenes population in the facility was destroyed by the ListexP100TM product. “I concluded that the genetic diversity of the bacteria in the facility was too high and that the bacteriophages could not be used as a control measure. However, there is much we do not understand about bacteriophages, and with a few adjustments, we might be able to use them in the food industry.”

Microbiological and molecular characterisation of L. monocytogenes

The bacteria were isolated and purified using basic microbiological culturing. Characterisation was done based on specific genes present in the bacterial genome. “I amplified these genes with polymerase chain reaction (PCR), using various primers targeting these specific genes,” Dr Strydom said. Some amplification results were analysed with a subsequent restriction digestion where the genes were cut in specific areas with enzymes to create fragments. The lengths of these fragments can be used to differentiate between strains. “I also compared the whole genomes of some of the bacterial strains.” The bacteriophages were then isolated from waste water samples at the facility using the isolated bacterial strains. “However, I was not able to isolate a bacteriophage that could infect the bacteria in the facility.

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