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The impact of cereal killers on food security

25 March 2022 | Story Leonie Bolleurs | Photo Charl Devenish

Prof Liezel Herselman Inuagural Lecture — At the inaugural lecture were from the left: Prof Danie Vermeulen, Dean of the Faculty of Natural and Agricultural Sciences, Prof Liezel Herselman, Dr Adré Minnaar-Ontong, Senior Lecturer in the Department of Plant Sciences and Subject Head of Plant Breeding, and Dr Molapo Qhobela, Vice-Rector: Institutional Change, Strategic Partnerships and Societal Impact.

Prof Liezel Herselman, Academic Head of the Department of Plant Sciences at the University of the Free State (UFS),) delivered her inaugural lecture on the Bloemfontein Campus this week (24 March 2022). The theme of the lecture was the ongoing battle against destructive cereal killers.

With 28 years of extensive experience as a researcher, her work focuses on marker-assisted disease resistance breeding in wheat within a South African context. When she joined the UFS in 2004, Prof Herselman decided to apply her research expertise in marker-assisted breeding to the problems faced by wheat producers in the Free State and Northern Cape. The Free State is one of the major dryland wheat production areas in South Africa, while irrigation wheat is produced along the major rivers in the Northern Cape.

Protection against fungal diseases

Concentrating specifically on Fusarium head blight (or wheat scab) and three rust diseases – leaf rust, stem rust, and stripe rust – she has done work to provide wheat plants with ‘tools’ to protect themselves against these fungal diseases.

According to Prof Herselman, there are many genes available in different wheat genotypes and related grass species that provide excellent protection against various races of these diseases. “Some of these genes provide protection or resistance from the seedling stage, while others provide resistance at the adult plant stage. We are thus aiming to combine as many of these genes as possible into a single wheat cultivar, without compromising yield and bread-making quality.”

She says the genes are combined by making crosses between resistant and susceptible cultivars or lines. Conventionally, through a time-consuming process, the incorporation of these genes is tested in the greenhouse and field by infecting plants with the disease to see which plants are resistant and which are not.

They can, however, follow the transfer of these genes to newly developed lines by applying molecular markers. Prof Herselman explains: “A molecular marker is a genomic fragment linked to the gene, which we can follow in the offspring we create from the crosses using different DNA techniques in the laboratory. This enables us to select new wheat lines that contain the highest number of resistance genes. The identified best lines are then used in further crosses and/or released as pre-breeding lines to commercial wheat breeding companies.”

Impact on food security

Her research has an impact on society by providing food security to both commercial and small-scale producers, as well as the end users of wheat (people buying bread and other wheat products). As researcher, it is also important for her to send out students to the workplace who can continue with this task in future.

Prof Herselman believes that when cultivars with fungal-disease tolerance or resistance are released and used by producers, it not only reduces the cost of spraying against diseases, but also increases yields by protecting the crop against fungal diseases. “We live in a world where the population is increasing daily, but land available for agriculture is not increasing and some areas are even lost due to urban development. Increasing yield in available production areas will thus have a positive impact on food security,” she says.

Besides contributing to the country’s food security, she takes pleasure in every aspect of her work. Although she misses the hands-on part of the work as academic head of the department and getting her hands dirty, she still enjoys managing the different research projects (from the conceptualisation phase to data analysis and publishing of results). The part she loves the most is to see the growth in her postgraduate students – from the moment they enter the laboratory for the first time until the day they walk out of the laboratory with their degrees.

“It adds purpose to my life knowing that I have made a difference in a student’s life and equipped him or her with the necessary tools to be successful in the marketplace. Being able to share your knowledge is a gift, but with that gift comes a lot of responsibility as well. I am, however, up for the challenge,” concludes Prof Herselman.

News Archive

Nanotechnology breakthrough at UFS

2010-08-19

Ph.D students, Chantel Swart and Ntsoaki Leeuw

Scientists at the University of the Free State (UFS) made an important breakthrough in the use of nanotechnology in medical and biological research. The UFS team’s research has been accepted for publication by the internationally accredited Canadian Journal of Microbiology.

The UFS study dissected yeast cells exposed to over-used cooking oil by peeling microscopically thin layers off the yeast cells through the use of nanotechnology.

The yeast cells were enlarged thousands of times to study what was going on inside the cells, whilst at the same time establishing the chemical elements the cells are composed of. This was done by making microscopically small surgical incisions into the cell walls.

This groundbreaking research opens up a host of new uses for nanotechnology, as it was the first study ever in which biological cells were surgically manipulated and at the same time elemental analysis performed through nanotechnology. According to Prof. Lodewyk Kock, head of the Division Lipid Biotechnology at the UFS, the study has far reaching implications for biological and medical research.

The research was the result of collaboration between the Department of Microbial, Biochemical and Food Biotechnology, the Department of Physics (under the leadership of Prof. Hendrik Swart) and the Centre for Microscopy (under the leadership of Prof.Pieter van Wyk).

Two Ph.D. students, Chantel Swart and Ntsoaki Leeuw, overseen by professors Kock and Van Wyk, managed to successfully prepare yeast that was exposed to over-used cooking oil (used for deep frying of food) for this first ever method of nanotechnological research.

According to Prof. Kock, a single yeast cell is approximately 5 micrometres long. “A micrometre is one millionth of a metre – in laymen’s terms, even less than the diameter of a single hair – and completely invisible to the human eye.”

Through the use of nanotechnology, the chemical composition of the surface of the yeast cells could be established by making a surgical incision into the surface. The cells could be peeled off in layers of approximately three (3) nanometres at a time to establish the effect of the oil on the yeast cell’s composition. A nanometre is one thousandth of a micrometre.

Each cell was enlarged by between 40 000 and 50 000 times. This was done by using the Department of Physics’ PHI700 Scanning Auger Nanoprobe linked to a Scanning Electron Microscope and Argon-etching. Under the guidance of Prof. Swart, Mss. Swart en Leeuw could dissect the surfaces of yeast cells exposed to over-used cooking oil.

The study noted wart like outgrowths - some only a few nanometres in diameter – on the cell surfaces. Research concluded that these outgrowths were caused by the oil. The exposure to the oil also drastically hampered the growth of the yeast cells. (See figure 1)

Researchers worldwide have warned about the over-usage of cooking oil for deep frying of food, as it can be linked to the cause of diseases like cancer. The over-usage of cooking oil in the preparation of food is therefore strictly regulated by laws worldwide.

The UFS-research doesn’t only show that over-used cooking oil is harmful to micro-organisms like yeast, but also suggests how nanotechnology can be used in biological and medical research on, amongst others, cancer cells.

Figure 1. Yeast cells exposed to over-used cooking oil. Wart like protuberances/ outgrowths (WP) is clearly visible on the surfaces of the elongated yeast cells. With the use of nanotechnology, it is possible to peel off the warts – some with a diameter of only a few nanometres – in layers only a few nanometres thick. At the same time, the 3D-structure of the warts as well as its chemical composition can be established.

Media Release
Issued by: Mangaliso Radebe
Assistant Director: Media Liaison
Tel: 051 401 2828
Cell: 078 460 3320
E-mail: radebemt@ufs.ac.za
18 August 2010

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