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
Makerere Researchers Call for Urgent Conservation of Medicinal Plants in Eastern Uganda
Researchers from the Department of Plant Sciences, Microbiology, and Biotechnology at the College of Natural Sciences (CoNAS), Makerere University have highlighted the urgent need to conserve medicinal plants in the face of increasing threats from climate change, over-harvesting, and habitat destruction.
Despite Namutumba District’s rich diversity of medicinal plants, conservation efforts are limited, and several species are already classified as globally and nationally threatened. This highlights the urgent need for focused conservation strategies to safeguard these vulnerable medicinal plants.
Under a project titled “Knowledge, Attitudes, and Conservation of Commonly Traded Medicinal Plants in a Climate-Changing Environment in Eastern Uganda,” a team of researchers led by Dr Patience Tugume documented 174 medicinal plant species. The goal was to assess the existential threats facing these plants due to unsustainable harvesting practices and the lack of effective conservation measures. These species are widely used to treat various health conditions, including malaria, syphilis, diabetes, hypertension, and certain cancers. The findings of the study are intended to guide the development of species-specific, evidence-based interventions to curb possible extinction and loss of medicinal plant resources. The research revealed troubling trends in the availability of key medicinal plants, including:
- The herbalists mostly collected their medicinal plants from bushlands (92.0%), markets (82.3%) and wetlands (74.7%) and were rarely cultivated. This is of great concern regarding the conservation and future availability of these resources.
- It was noted that 36% of the herbal products were made from roots, which presents a conservation threat since the heavy utilization of roots affects the regeneration of the medicinal plants.
- Common plants used were: Kigelia africana (Naibere), Erythrina abyssinica (Ekiyirikiti) and Geranium sauveolens (Lokowe). Kigelia africana was the most cited species by the herbalists, indicating heavy utilization and a high conservation threat if deliberate measures are not taken to ensure its future availability.
- Almost all respondents (289, 96.3%) acknowledged a considerable decline in the availability of 13 medicinal plants species including Aloe wollastonii (Ekigagi), Commiphora africana (Nkulidho), Myrica kandtiana (Mukikimbo) and Acacia sieberiana (Mufundawuzi).
- Four plant species i.e. Tamarindus indica (Enkoge), Warburgia ugandensis (Balwegira), Mitragyna rubrastipulata (Mutamatama) and Mondia whitei (Mulondo) appear on the Red List of Globally and Nationally Threatened Species and were mentioned among the plants whose population has greatly declined.
- The causes of decline in availability of medicinal plants included climate change, overharvesting, agricultural expansion, habitat destruction, land use change and inadequate regulations.
- There were no medicinal plant conservation efforts by herbalists.
The study recommended the following practices to ensure conservation of the medicinal plants:
- Promote the use of sustainable harvesting techniques to ensure conservation of medicinal plants.
- Conduct capacity building for stakeholders in the medicinal plants sector on conservation, value addition and standardization.
- Establish community botanical gardens raw plant collection and sensitization programmes.
- Advocate for agroforestry among herbalists to reduce the dependence on natural habitats.
- Develop and enforce regulations on accessing natural areas for medicinal plants.
- Promote conservation awareness campaigns.
Research Dissemination in Namutumba District
At the research dissemination workshop held in Namutumba District on 23rd July 2025, and attended by district leaders, researchers, and local herbalists, the project team led by Dr Patience Tugume expressed hope that the insights gained from the project, particularly in medicinal plants conservation approaches, will be invaluable for minimising the decline in medicinal plants.
In her remarks, Dr Tugume, thanked the Government of Uganda through the Makerere University Research and Innovations Fund (MakRIF) for funding the project. She expressed gratitude to the research team composed of Dr Abubakar Sadik Mustafa, Dr Jamilu E. Ssenku, Dr Savina Asiimwe, and Dr Abdul Walusansa who have worked with her closely from project inception in February 2024. She further thanked the research assistants and all respondents, mainly the herbalists that participated in the study.
In a special way, she appreciated Mr. Fred Aggrey Bangu (Resident District Commissioner), Mr. Ofwono Emmanuel (Chief Administrative Officer), Mr. Kiire Noah (Communication Officer), Mr. Mugunywa Enock (District Community Development Officer), Mr. Kirya Moses (District Environmental Officer), Mr. Bamusubire William (District Forest Officer) and the leaders of herbalist associations for providing support throughout the study and sparing time to attend the dissemination workshop.
Addressing the participants, the Resident District Commissioner, Mr. Fred Aggrey Bangu urged all stakeholders to engage in a collaborative discussion on how the study findings can be translated into practical solutions to promote sustainable use and conservation of commonly used medicinal plants in Namutumba District amidst adverse effects of climate change.
Mr. Ofwono Emmanuel, the Chief Administrative Officer, praised the Makerere research team for selecting Namutumba as the study area. He said the research served as an eye-opener to the district officials and community, especially regarding the pressure exerted on natural medicinal resources.
Report compiled by Dr Patience Tugume and Dr Abubakar Sadik Mustafa – Department of Plant Sciences, Microbiology and Biotechnology, CoNAS, Makerere University
Natural Sciences
Beyond Being a Dean of Science & Vice Chancellor Emeritus, Prof. Luboobi was a Friend. Just That!
Prof. Livingstone Sserwadda Luboobi, Africa’s Icon of Mathematics is gone. The continent has lost a true giant in the field of mathematics, specifically biomathematics. This dynamic and evolving discipline, which applies mathematical principles to the study of biological systems and phenomena, has been deeply shaped by Prof. Luboobi’s legacy. At Makerere University and across Africa, his influence is etched into the fabric of research, mentorship, and innovation. Prof. Luboobi’s contributions have left lasting marks, on the hundreds, perhaps thousands, of lives he touched directly and indirectly. Each of us carries a unique memory, a lesson, or an inspiration drawn from his life and work. We will dearly miss Prof. Luboobi, a brilliant mind, a generous mentor, and a true icon of African science.
To me and my peers, he was our Dean, Faculty of Science in 1995, and he read-out our names at our graduation in January 1999. Later in 2004 as Vice Chancellor, he signed off my official 4-year PhD study leave in Scandinavia. When the 4 years elapsed before I could complete, we returned to the table and successfully negotiated for extra 2 years of grace which enabled me to complete in excellence in January 2010.
Lately, after his retirement, we found ourselves closely intimate, sharing deeper thoughts on a number of social, development, strategic leadership and governance, and academic matters. As a plant biologist, spending time with a retired Professor of Mathematics, one could wonder what we would possibly have to talk about. And yet, our discussions were rich and thought-provoking. One moment that left a lasting impression on me was his quiet humility. Despite the respect and priority I extended to him, he never assumed entitlement. If he sensed I was busy, he would simply wait outside my office, whether at the Botany Building or my current Dean’s office at CONAS, without interrupting. That gesture spoke volumes.
We often talked about science, and I had much to learn from him. I asked how he had managed to start and sustain the Uganda Mathematical Society (UMS), since we were in the process of setting up the Biology Society of Uganda (BioSU) at the time. I also wanted to hear about his journey – from his undergraduate days to becoming a retired professor. As he shared his story, pausing to catch his breath after long sentences, I sensed he was deeply concerned about something. His concern was that, as of 2017, nearly all senior academics at Makerere University had begun their careers humbly as teaching assistants and risen through the ranks in various disciplines, but that opportunity had since been lost.
He believed that trying to establish a sustainable staffing system without a pool of junior staff, selected directly from the best-performing undergraduate students, was a risky path for the university’s future. With a troubled tone, he said: “I wonder how you people will manage university staffing in the long term when you have removed the foundation…” There were many lessons in that conversation for me.
In October 2023, I started assembling a grant application together with my European and American colleagues (5 Universities) for submission to National Science Foundation (NSF, USA), addressing a certain plant disease conundrum in East Africa. I realized Prof. Luboobi’s expertise in Biomathematics could be relevant. I co-opted him along with another colleague from the Department of Mathematics. I was fascinated at the express knowledge he displayed in modelling biological systems, and in our case, plant disease modelling. Much as his physical strength was less, the intellect was razor-sharp. Even though we didn’t succeed on that attempt, I had numerous other lessons to learn from his seniority.
We shared personal stories. I re-learnt that living simple as much as possible helps a lot. Although this was not new, hearing it from one you respect takes on a whole new meaning. If I died today, I wonder what my peers or junior colleagues would say about me? I would not hear it, though. I am happy I had chance to tell Prof. Luboobi what he meant to me when he was still alive.
I regret his death. We usually say it is untimely, but will death of a loved one ever be timely? Holy Scripture says, “Seeing his days are determined, the number of his months is with You; You have appointed his bounds that he cannot pass.” – Job 14:5. This is an emphasis of God’s sovereignty over life and death, highlighting that He determines the length of a person’s life and sets unchangeable limits, just as He does in setting boundaries and limits for all His creation. Prof. Luboobi could not cross the boundary set by the creator.
I am grateful that the Principal, College of Natural Sciences (CoNAS), Makerere University and his team did their best to mobilize support at the most critical moment of need. I am grateful to God for gifting Makerere University with Prof. Luboobi, and for allowing me in particular a chance to walk a little close with him in his evening days of his life between 2023-2025.
Good bye Prof. Livingstone S. Luboobi! Go and serve God with the angels. We will also join you, in the course of time! See you later when that time comes!
*****15 students from different departments at CoNAS are showcasing their projects.
Over 300 Ugandan innovators, among them students from the College of Natural Sciences (CoNAS) and other science-based colleges at Makerere University are participating in the 2025 National Science Week exhibition, currently underway at the Kololo Independence Grounds.
Launched in 2021, the National Science Week is an annual event organized by the Science, Technology, and Innovation (STI) Secretariat under the Office of the President. The exhibition serves as a strategic platform for showcasing Uganda’s advancements in science, technology, and innovation, both at the national level and on the global stage.
Held under the theme “Made in Uganda: Innovation to Market”, the 2025 edition (running from 15th-20th June) aims to highlight the country’s growing capacity to transform home-grown scientific ideas and research into viable, market-ready products and technologies.
Key highlights from the official launch of the National Science Week
During the official launch held on 13th May 2025, the Minister of Science, Technology, and Innovation, Hon. Dr. Monica Musenero Masanza, outlined several milestones Uganda has achieved over the past year, including:
- The commencement of clinical trials for locally developed therapeutics, marking a significant step in Uganda’s biopharmaceutical sector.
- Notable growth in the electric vehicle (EV) industry, including the deployment of over 5,000 electric motorcycles and 27 electric buses across the country.
- Establishment of critical green infrastructure, including 140 battery swapping stations and more than 30 direct current (DC) fast chargers nationwide.
According to the Minister, these developments demonstrate Uganda’s advancing capabilities in green technology and sustainable mobility solutions.
The Minister also highlighted additional achievements by the STI Secretariat, including the revitalization of Sukulu Phosphates, the launch of both the Deep Tech and Climate Tech summits, and the operationalization of vaccine production lines for both human and animal health. Dr. Musenero expressed gratitude to the Government of Uganda for its continued support, emphasizing its strategic vision of leveraging science, technology, and innovation as a transformative vehicle to position Uganda as a continental leader in deep tech innovation.
The 2025 National Science Week Activities
The National Science Week is designed to be an interactive experience for all attendees. According to Ms. Cathy Muhumuza from the STI, the exhibition will feature various activities including the official opening by the President of the Republic of Uganda, H.E. Yoweri Kaguta Tibuhaburwa Museveni, expected to take place on Thursday, 19th June 2025. Other activities will include policy dialogues, the Academia Day dedicated to young innovators, and the Investor Day providing a platform for innovators to connect with potential investors.
Additionally, the event will host a “Made in Uganda Supermarket,” allowing visitors to purchase products directly from exhibitors.
CoNAS Students’ projects
Among the many innovators featured at the exhibition are several talented student teams from CoNAS, presenting a diverse array of projects across scientific disciplines, including biotechnology and green energy. Guided by their lecturers and coordinated by Prof. Juma Kasozi, Deputy Principal of CoNAS, the students are showcasing the following projects:
- Anti-fungal and Anti-bacterial Gel Research Project
Team Leader: Mwebaze Bruce
Team Members: Atim Martha, Sebastian Jordan
This project explores the development of a topical gel with both anti-fungal and anti-bacterial properties, aimed at improving public health outcomes in communities with limited access to conventional treatments. - Minoxidil Production for Hair Regrowth
Team Leader: Keinembabazi Melissa
Team Members: Hashima Nanyiri, Nkamusiima Andrew
Focused on producing affordable, locally made Minoxidil, this project aims to provide a cost-effective solution for treating hair loss. - Infrared Biosensor for Aflatoxin Detection
Team Leader: Rubeihayo Randolp
Team Members: Namuleme Martha, Wabitereza Teddy
This innovation utilizes spectrophotometry to develop an infrared biosensor capable of detecting harmful aflatoxins in food, contributing to food safety and public health. - Biofuel Production from Water Hyacinth
Team Leader: Bill Garvin
Team Members: Kalanguka Patience Pearl, Nuwagaba Victor
The project converts invasive water hyacinth into sustainable biofuels using hydrothermal liquefaction, offering an environmentally friendly alternative energy source. - Automobile Fuel Gauge Detector
Team Leader: Ayebare Sam
Team Members: Achieng Rosemary, Nakirinda Winnie
This project involves the development of a reliable fuel gauge detector to improve vehicle fuel management and efficiency.
-
General2 days agoAdmission Lists for Postgraduate Programmes 2025/26
-
Health1 week agoCall for Apllication: The James M. Ntambi Postdoctoral Fellowship
-
General5 days agoMakerere University Repositions Doctoral Training to Build Africa-Centered Scholarship
-
General5 days agoAcademic Year 2025/2026 at Makerere Begins With Freshers’ Orientation
-
General2 weeks agoIGAD Board Visits Mak, Reiterates Commitment to Promoting Academic Mobility