Plant pathologists are excellent problem solvers

Posted on February 02, 2021

Scarce skills in Natural and Agricultural Sciences
Focus on a plant pathologist: Dr Mahlane Godfrey Kgatle - Department of Plant and Soil Sciences and Postdoctoral fellow: FABI

Q: What is plant pathology?
A: Plants are important to us in many ways: they provide timber for shelter (forestry), medicine, cosmetics (which my wife loves) and food (which I love). Like animals and humans, plants can also suffer from diseases caused by a wide range of microorganisms or pathogens, such as fungi, bacteria, viruses and nematodes. Plant pathology is the scientific study of diseases caused in plants by infectious microorganisms (pathogens) and environmental conditions (physiological factors). In fact, there are far more plant diseases than human or animal diseases simply because of the large number of plant species used in agriculture, horticulture and forestry.

Why is it so important to keep plants healthy? Plant pathology developed as a field of study in the 1800s after Ireland experienced a famine caused by a plant pathogenic microorganism, Phythophthra infestans. At the time, potatoes were the staple food in Ireland and Phythophthra infestans caused potato late blight, which resulted in rot of roots and tubers and the loss of the potato crop. A million Irish people starved to death and another million emigrated.

Today there are still many other diseases that need to be managed, for example Alternaria leaf blight and Phoma black stem, caused by Alternaria alternata and Phoma macdonaldii respectively. These diseases rapidly reduce leaf count on the plant and also cause stem lodging (breaking). In the case of the sunflower plant, the grain fill is hampered and the disease can reduce the yield by up to 80%, resulting in the loss of millions of rand and many jobs.

The threat to human life posed by the COVID-19 pandemic should be an important reminder to us all that a clear understanding of plant diseases caused by micro-organisms (pathogens) is vital in plant disease management to ensure food security.

Q: What did you study to become a plant pathologist
A: My core modules during my undergraduate and honours studies were Microbiology, Botany, Genetics, Biochemistry, Zoology and Plant Pathology. My master’s and PhD research focused mainly on the initiation, design and conducting of experiments that focus on plant-pathogen interactions, as well as the analysis, interpretation and publication of the results that revealed how plants are able to either resist disease or are affected by it.

Q: What does a plant pathologist’s job entail?
A: Farmers rely on plant pathologists for advice on disease-management strategies to regularly produce high-quality crops. Entry-level careers can involve basic research and lab work, while advanced careers may involve more applied research and possibly also teaching.

The job entails the identification and description of plant diseases and working with farmers to ensure that diseases are effectively controlled.

Q: Describe a typical day in the life of a plant pathologist.
A: My current responsibilities include research, diagnostics and extension. My research focuses on engagement with fellow scientists, agricultural organisations such as Grain SA, SANSOR and the Oilseeds Advisory Committee, and local farmers to identify crop problems, prescribe suitable solutions and give technical advice based on my research findings by communicating complex scientific concepts in layman’s terms to ordinary South Africans from various cultural groups.

Research is essential to remain informed on what other scientists around the world are doing and to build knowledge and facilitate understanding of plant-pathogen interactions. This understanding will help to limit the impact of pathogens on crops and increase crop resistance, thereby increasing food production and introducing changes to policies in the field.

My extension responsibilities include supporting farmers and actively seeking to discover procedures that will increase crop yields, improve farmland productivity and reduce losses due to disease and insects. Regular monitoring of plant diseases allows for early detection and response to contain and eradicate or manage plant pests and diseases. Appropriate training and the provision of advisory services to small-scale and commercial farmers will help to close the gap in production between commercial and subsistence farmers.

In brief, my day starts with meetings with fellow academics and industry representatives, followed by disease identification and pathogen description of samples received from farmers and industry. Sometimes I spend a day in the field identifying and collecting samples. I usually end the workday by attending to emails to address issues that have been raised by fellow academics and industry, and also planning for the next day.

Q: Do you specialise in a specific aspect of plant pathology?
A: As a plant pathologist I am familiar with disease epidemiology, diagnostics and management. However, as a fellow, my field of specialisation is the diagnosis and description of diseases.

Q: Which skills does a plant pathologist need?
A plant pathologist should be able to do research, analyse and interpret data, and should have good communication skills.

Q: Why did you decide to become a plant pathologist?
While still at school, I was unaware of plant pathology as a career, so initially I enrolled for a degree in Microbiology at the University of Pretoria. When I was introduced to plant pathology in my third year, and after discussions with my lecturers (the late Prof Terry Aveling and Prof Jacquie van der Waals), I became aware of how it is applied in the industry and how it has a direct impact on food security. It is then that I decided to pursue a career in plant pathology and I have never regretted it.

Q: In which fields / industries are plant pathologists employed?
A: Opportunities for plant pathologists abound. Plant pathology requires innovative problem-solving technologies to ensure product integrity and safety from seed to plate. Infested seed (seed pathology) can play a role in the transmission of disease pathogens. Opportunities also exist in the areas of field and post-harvest pathology.

Plant pathologists can teach at universities or do research at institutes such as FABI, the Agricultural Research Council (ARC),  the Council for Scientific and Industrial Research (CSIR), the South African Bureau of Standards (SABS), the Perishable Produce Export Control Board (PPECB), agrochemical and seed companies, retail, exporting and importing companies, the nursery industry, co-operatives, the food industry and private estates. Plant pathologists can also work in private practice and operate as consultants.

Q: Do you have any advice for prospective plant pathologists?
A: The problem of food security for the world’s population is widely recognised, and the effective management of plant diseases has an important role in meeting this challenge. Plants account for more than 80% of the human diet and are therefore essential for food security. The FAO estimates that pests and diseases are responsible for about 25% of crop loss. Furthermore, some of these pathogens produce (myco)toxins that contaminate and may be harmful to animals and humans when consumed.

Plant pathologists in developing countries need to find solutions for local farming problems. New, innovative technologies that are being developed to enhance the field of plant pathology include biotechnology, which provides a better understanding of the genetics of both the plant and the pathogen; precision agriculture using drones and sensors; biological and chemical control; the use of CRISPR/Cas9 technology for resistance and the development of desirable traits in crops; disease prediction; and chemical ecology/pheromones. All of these will be at your disposal to make improvements in the system. 

Plant pathology speaks to nine of the United Nations’ Sustainable Development Goals (SDGs). The most relevant is the achievement of food security and zero hunger. As a prospective plant pathologist, your research can contribute to the regulation of agriculture and forestry and help to meet the UN’s SDGs.

Q: Do you think your talent as a chess player contributed to your pursuit of science?
A: Certainly! I believe that chess and many other games that develop problem-solving skills should be promoted at schools and even at workplaces. Chess is a social game and is an excellent way to learn problem-solving skills, and I recommend it to all would-be plant pathologists.

Q: What advice would you have given to your young self?
A: Expand your skills set and network. Seek out every opportunity to develop your communication skills and increase your scientific knowledge. There are no silly questions, so make friends with your lecturers and ask all the questions you need to be answered. Have fun, enjoy the ride and make it one you will be proud to look back on!

- Author Martie Meyer
Published by Martie Meyer

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