Natural Sciences
Banana’s Large Plant Body Size an Advantage to Disease Control – Mak Scientists
Unlike for plants, in animals especially humans, body mass index (BMI, which is a person’s weight divided by the square of height) is a measure of physical health and pre-disposure to conditions like obesity. BMI does not make sense in plant health because of differences between plant and animal physiological systems.
However, large body size in plants may have some advantages. Apart from controlling a larger proportion of available resources and space within crowded vegetation, what other advantage does a large plant body size offer to an individual plant?
The banana’s plant body architecture
From the botanical point-of-view, the banana plant is a gigantic herb. A plant that is a herb or “herbaceous” is unable to undergo “secondary growth” and cannot form wood during its vegetative development.
The banana plant springs from an underground “true stem”, also called the “corm” or “rhizome”, to form a false stem, also called a “pseudostem” of 2-7 m height. The pseudostem is composed of the basal portions of leaf sheaths and is crowned with a rosette of 10 to 20 oblong to elliptic leaves that sometimes attain a length of 2-4 m and a breadth of 70 cm.
In mature banana plants, true stem emerges at the top of the pseudostem and bends downward to become a bunch of 10 to 300 individual fruits, or fingers, grouped in clusters, or hands, of 3 to 22. The edible part of the bunch is the female. In contrast, the inedible distal part, including the purple-colored cone-shaped end (locally known in some Ugandan dialects as “omukanaana” or “empumumpu”) constitutes the male part of the bunch.
How is the giant banana size an advantage in disease control?
A new study, titled “Xanthomonas campestris pv. musacearum Bacterial Infection Induces Organ-Specific Callose and Hydrogen Peroxide Production in Banana” and led by a team of scientists at the Department of Plant Sciences, Microbiology and Biotechnology at Makerere University in collaboration with the University of California, Davis, USA, shows how the giant banana body size can be used to control banana Xanthomonas wilt (BXW) disease.
According to Prof. Arthur Tugume, the lead scientist of this study and expert in plant pathology, when plants get infected, they respond instantly by implementing different strategies that limit the multiplication and/or mobility of the disease agents (pathogens). “For example, plants rapidly produce reactive oxygen species (ROS) such as hydrogen peroxide, superoxide ions, and hydroxyl ions. These ROS act as rapid messengers in the plant tissues to activate additional responses spreading over the entire plant body. This helps the plant’s distant tissues or organs to be aware and prepare advance defenses against the intruding pathogens”.
Prof. Dinesh-Kumar the project’s research collaborator based at the University of California-Davis, USA and expert in plant biology explains that “disease is a form of stress in plants and plants cannot perform well their biological functions when they are sick since they have to spend a lot of energy fighting against the disease. This is why disease control is important to enable plants grow well and yield high.”
The research indicates that ROS set in motion additional processes to ensure limited impact of disease and pathogens on the plant. For example, Hydrogen peroxide (H2O2), which is a ROS, has direct bactericidal, fungicidal or other anti-effects on the pathogens. Also, following H2O2 production, a unique plant carbohydrate, named “callose” starts to accumulate in large quantities within plant cells as a means of fortifying plant tissues. Callose differs from the other usual plant carbohydrates such as starch or cellulose because of the way its structures are formed.
Increased production of callose acts as a roadblock to any pathogen e.g., bacteria by limiting bacterial movement that would otherwise allow ease of attack on other tissues or cells at distant locations in the plant. “Although these plant defense responses are rapid, plant organs that are distant from the site of pathogen attack can be instrumental and block progression of bacteria or other pathogens by depositing callose in advance at strategic points” Prof. Tugume explains.
However, Prof. Tugume notes that callose participates also in many other normal developmental processes of plants, and for that reason, there is always some “housekeeping” callose in the plant tissues even without pathogenic infection. “This means that one must be able to accurately and quantitatively distinguish between ‘stress-induced’ and normal ‘housekeeping’ callose”, he adds.
How was the study done?
In this study, the researchers used young (2.5-months old) banana plantlets that had been generated from tissue culture at Kawanda Agricultural Research Institute. They then infected the plantlets with a bacterium called Xanthomonas campestris pv. musacearum (Xcm). This bacterium is the causative agent of banana Xanthomonas Wilt (BXW), the most destructive disease of bananas in East and Central Africa (ECA).
The banana leaves, pseudostems, corms and roots were analyzed for callose and compared with the control plants that had been inoculated with water instead of bacteria. H2O2 production was monitored by “DAB staining”, and by “spectrophotometry” while the analysis of callose was done by two methods: staining and visualization of callose using florescence microscopy, and using “Sandwich Enzyme-Linked Immunosorbent Assay” methods.
What did the researchers discover and how can it be used in BXW disease control?
This study revealed that the underground corm tissues assemble the stiffest resistance against BXW by depositing the highest concentrations of callose, while the pseudostem produced the highest quantities of H2O2. This is interesting for three (3) main reasons:
- Firstly, Xcm bacteria often enter through the leaves in regular plantation husbandry; hence, the corm being distant from leaves gives it an anatomical advantage in promoting the ability of lateral plants to escape Xcm infection.
- Secondly, the corm is an organ of perennation supporting vegetative and perennial continuity of the crop across seasons; hence it is charged in ensuring a disease-free next generation by severely constraining “mother-child transmission” of Xcm bacteria.
- Thirdly, the control of BXW now becomes easy when farmers are observant to the first aerial disease symptoms because Xcm is strongly constrained by bottlenecks in the pseudostem and corm.
Therefore, at the onset of aerial symptoms, diseased peudostems should immediately be removed by aseptically cutting them off at the corm without interfering with symptomless lateral shoots, which allows continuous food production and disease control to go on simultaneously. This is facilitated by the large size of the banana plant because at the onset of leaf symptoms (2.5 to 5 meters away from the corm), the bacteria have not yet arrived at the base of the pseudostem where the diseased plant can be cut off from the corm. This gives chance to a farmer to eliminate the infected pseudostems early (in 1 to 7 days) since the appearance of leaf symptoms.
This research was part of the PhD studies for Mr. Abubakar S. Mustafa at Makerere University and University of California, Davis. According to Mr. Mustafa, these discoveries make the management of BXW in banana plantations easy as long as the farmers are observant and act fast by removing diseased plants aseptically.
This study has been published by the American Phytopathological Society (APS) in an open access journal, “PhytoFrontiers”, and is freely accessible on https://apsjournals.apsnet.org/doi/full/10.1094/PHYTOFR-11-21-0073-R.
This study was funded by the Bill and Melinda Gates Foundation through the National Agricultural Research Organization (NARO), Uganda. The project had partners including the International Institute of Tropical Agriculture (IITA), the Alliance for Bioversity International and International Centre for Tropical Agriculture (CIAT) and Centre for Agriculture and Bioscience International (CABI).
For more details, contact;
Prof. Arthur Tugume
Lead Scientist
College of Natural Sciences (CoNAS)
Makerere University
Email: arthur.tugume@mak.ac.ug
Tel: +256772514841
Mr. Abubakar S. Mustafa
Co-Author and PhD student on the study
Email: mustafa.abubakar.sadik@gmail.com
Tel: +256702813233
Hasifa Kabejja
Principal Communication Officer
College of Natural Sciences (CoNAS)
Makerere University
Email: pr.cns@mak.ac.ug
Tel: +256774904211
Natural Sciences
Change of Guard: Prof. Michael Owor Hands Over Office of Dean, School of Physical Sciences to Prof. David Ssevviiri
Prof. Michael Owor has officially handed over the office of Dean, School of Physical Sciences to Prof. David Ssevviiri. Prof. Owor has served as Dean since 1st February 2022. Following his appointment by the University Council, Prof. Ssevviiri will serve as Dean for the next four years, effective 6th May 2026.
Handover Ceremony
Held on 28th May 2026 in the office of the Dean, the handover ceremony was overseen by Makerere University Chief of Internal Audit, Mr. Patrick Akonyet. It was attended by the Deputy Principal of the College of Natural Sciences (CoNAS), Prof. Juma Kasozi; the Head of the Department of Chemistry, Dr Emmanuel Tebandeke; the representative of the Head of the Department of Physics, Dr. Nicholas Kwarikunda; the representative of the Head of the Department of Geology and Petroleum Studies, Dr Denis Mutebi; the College Human Resource Officer, Ms. Kevin Nabiryo Mikwano; and the College and School Registrars.
Remarks from the College leadership
On behalf of the College leadership, Prof. Juma Kasozi commended Prof. Owor for his dedicated service and leadership throughout his tenure and congratulated Prof. Ssevviiri upon his appointment, wishing him success in his new role.
Achievements and remarks by the outgoing Dean
During his tenure, Prof. Owor chaired the School Academic Board and several key committees, including the Establishment and Appointments Committee, the Examination Malpractices Committee, and the Irregularities and Appeals Committee. He also presided over MSc viva voce examinations and PhD public defenses. Under his leadership, he ensured the timely submission of results, eliminated academic backlogs, and strengthened the coordination of graduate examinations, while also supporting the development and review of academic programmes. He has also served as the Patron of the CoNAS Students’ Guild.
In his remarks, Prof. Owor expressed gratitude to the University Council and Management for the opportunity accorded to him to serve as Dean. He also thanked the College leadership and staff for their support and reaffirmed his commitment to continue serving the University.
“I want to thank the University Management through the Chief Human Resource Officer for appointing me as dean, School of Physical Sciences for the last four years. I pledge my total support to the incoming Dean of the School. I also pledge to continue offering my services to the University through my mother Department, Geology and Petroleum Studies.”
Remarks from the Directorate of Human Resources
Representing the Directorate of Human Resources (DHR), Ms. Kevin Nabiryo Mikwano commended Prof. Owor for his leadership and contributions during his tenure.
“You have steered the school through curriculum reforms, staff development, student growth, and your commitment to both staff and students has not gone unnoticed. The foundation you have laid will continue to support the school’s progress. Thank you for your partnership with the Directorate of Human Resources in ensuring staff welfare, recruitment, and performance processes were handled with integrity and care.”
She also congratulated Prof. Ssevviiri on his appointment, expressing confidence in his leadership and vision. She reaffirmed the Directorate’s readiness to support him in team building, talent management, and fostering a positive working environment for academic, administrative, and support staff. She further encouraged staff to maintain strong collaboration with the incoming Dean, emphasizing: “The success of the school depends on how well we work together. At the DHR, our commitment is to ensure that policies, processes, and people management practices support the school’s academic mission. May this handover mark the beginning of another strong chapter for the School of Physical Sciences.”
Guidance on the officially recognized Government handover procedure
The Chief of Internal Audit, Mr. Patrick Akonyet, commended both the outgoing and incoming Deans and emphasized adherence to the Government of Uganda handover and taking of office procedures. He noted that strict compliance with established guidelines is essential for accountability, transparency, institutional continuity, and smooth transition of responsibilities.
Remarks by the incoming Dean
In his remarks, Prof. David Ssevviiri thanked Prof. Owor for his service and appreciated the University Management for his appointment. He emphasized the importance of the School of Physical Sciences in advancing science and innovation. “We have a responsibility of nurturing our students into innovative problem solvers. The future of Science depends on how well we prepare our students. Building on the successes of my predecessors, and working collaboratively through our Departments, we can further contribute to solving real world challenges.
Profile of Prof. David Ssevviiri
Prof. David Ssevviiri is a Ugandan mathematician and academic leader serving as an Associate Professor of Mathematics at Makerere University, College of Natural Sciences. He is widely recognized for his work in pure mathematics, particularly in algebra, module theory, ring theory, algebraic geometry, and local cohomology.
He holds a Bachelor of Science with Education in Mathematics and Chemistry from Makerere University, as well as a Master of Science in Mathematics from the same institution. He also obtained an additional MSc and a PhD in Mathematics from Nelson Mandela Metropolitan University (now Nelson Mandela University), South Africa. His doctoral research, A Contribution to the Theory of Prime Modules, focused on advanced module theory and algebra.
Prof. Ssevviiri joined Makerere University in 2011 as an Assistant Lecturer and rose to the rank of Associate Professor in 2022. He previously served as Head of the Department of Mathematics from 2015 to 2020, where he contributed to strengthening teaching, research collaboration, and postgraduate training.
His research interests include primeness and nilpotency in ring and module theory, torsion theory, radical theory, homological algebra, and the interaction between algebra and algebraic geometry. He has authored and co-authored several peer-reviewed publications in international journals, contributing significantly to advancements in abstract algebra.
Beyond teaching and research, he has contributed to mathematics development in East Africa through student supervision, external examining, and coordination of regional academic programs. He has also participated in initiatives aimed at promoting mathematics education and encouraging young people to pursue careers in science and technology.
Pictorial of the ceremony: https://drive.google.com/drive/folders/1pmWX5H46UHbFkTT-I4OIJwFbXIwuO6e1?usp=sharing
A team of researchers from Makerere University has presented findings of a study on the persistent poor performance in Biology in national examinations to senior officials at the Ministry of Education and Sports.
The findings were shared during a dissemination meeting attended by the Ministry’s top management, led by Permanent Secretary Kedrace Turyagenda.
The study, commissioned by the Ministry in 2023, was conducted by researchers from the College of Natural Sciences (CoNAS) and the College of Education and External Studies (CEES). It was spearheaded by Prof. Fredrick Muyodi as Principal Investigator, alongside Assoc. Prof. Josephine Esaete (Co-Principal Investigator) and Prof. Arthur Tugume among others.
Titled “Examining the Factors Accounting for Poor Academic Performance in Biology in Uganda’s National Examinations,” the study covered all regions of the country, engaging more than 5,200 respondents across 100 districts through surveys, interviews, and observations.
Key findings
The research identified limited field-based learning and poor digital access as the most critical and consistent challenges affecting both Ordinary and Advanced Level students across all regions.
At Advanced Level, the lack of project-based learning was also cited as a significant constraint. Learners reported limited engagement with Biology beyond the classroom, a factor that weakens conceptual understanding and application in examinations.
The study further highlighted the role of community attitudes and perceptions in shaping student performance in the subject.
Recommendations
The researchers recommended increased investment in field-based learning, including field trips and project work, as well as expansion of digital infrastructure to improve access to learning resources.
Other proposed measures include strengthening school laboratory facilities, enhancing teacher capacity through continuous professional development, promoting student engagement through academic clubs and mentorship programmes, and fostering stronger family and community support for science education.
Next steps
The research team is seeking funding to pilot targeted interventions, particularly in regions most affected by the challenges identified, and to develop a monitoring and evaluation framework to guide implementation.
The findings are expected to inform policy and interventions aimed at improving Biology performance and strengthening science education in Uganda.
By Dr. Alice Nabatanzi
At the Department of Plant Sciences, Microbiology, and Biotechnology (PMB) in the College of Natural Sciences, we are moving beyond the classroom to bring science to life. We are proud to showcase our innovative work with the Biotechnology Class of 2026. Our Product Development Centre has transitioned from theoretical research to practical, market-ready innovations. By applying advanced scientific principles, our students are developing tangible solutions that address everyday needs in nutrition, health, and industry.
Below are the latest products developed by our talented innovators:
- Nutrition & Food Technology: Vitamin A-rich bread, banana vinegar, food syrups, and fortified bio-snacks.
- Clinical Hygiene: Perfumes, Deodorants, Antibacterial gels, herbal toothpaste, shaving cream, and herbal mouthwash.
- Natural Wellness: Natural formulas for gut health, pain relief, cough lozenges, and nasal decongestants.
- Advanced Cosmeceuticals: Turmeric SunGuard patches, skin serums, toners, and anti-dandruff shampoo.
- Home & Industrial Solutions: Shoe deodorizing sprays, surface cleaners, and scented hygiene products.
- Agri-Tech: Natural bioindicator kits designed to monitor and improve soil health.
Through these initiatives, PMB continues to lead the way in re-engineering science for the benefit of our community and the world.
Meet the Biotechnology Class of 2026. While everyone else is still stuck in textbooks writing about “how things might work,” we’re in the lab making sure they actually do. We’ve officially moved past the days of just talking about science and stepped into the era of real-world industry. From our Product Development Centre to the global market, we are setting a new standard for Biotechnology at CoNAS. We aren’t just graduating with degrees; we’re graduating with the future in our hands.
What’s Next: We’re Just Getting Started
This is only the beginning. We’re already working on the next wave of products, from eco-friendly bio-packaging and better probiotics to smart-crop tech that will change how we eat, heal, and live. We aren’t just waiting for the future to happen we’re in the lab building it right now.
Dr. Alice Nabatanzi is a Senior Lecturer of Phytomedicine and Nutraceuticals at the College of Natural Sciences (CoNAS), Makerere University
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