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
Mak-CoNAS Wins CAD 0.8 Million Grant to Scale-up Fish Processing Technologies & Empower Women in Uganda
The College of Natural Sciences (CoNAS) at Makerere University has been awarded a highly competitive research grant worth CAD 0.8 million to implement the “NutriFishPLUS” project, which aims to scale up innovative fish processing technologies, improve market access, and empower women in Uganda’s fishing communities to boost incomes and livelihoods.
This project builds on the significant achievements of the previous ground-breaking NutriFish project (2019–2023), funded by the International Development Research Centre (IDRC) and the Australian Centre for International Agricultural Research (ACIAR) through the Cultivate Africa’s Future Fund Phase (CultiAF2). The achievements included: 1) establishing group savings schemes to improve access to capital by women and youth; 2) piloting solar tent dryers for processing silverfish (mukene), resulting in doubling of women’s incomes and tripling of the shelf-life to almost five months; 3) developing and test-marketing certified, nutrient enriched fish products, including baby food, sauce and fortified maize meal; 4) conducting comprehensive social and behavioural change interventions, leading to increased women’s participation in profitable ventures and 30% reduction in domestic violence in intervention areas. Despite these achievements, gaps still remain with regard to increasing production of high-quality Small Pelagic Fishes (SPFs) through adoption of solar tent dryers and raised drying racks; enhancing capacity of men, women and the youth in processing, packaging, branding and marketing; improving access to capital and lucrative markets for fish and fish products; and empowering women, youth and other marginalized groups in the small fish value chain; and strengthening resilience of fishing communities through diversified income streams.
NutriFishPLUS will be implemented by the Department of Zoology, Entomology and Fisheries Sciences, CoNAS, in collaboration with two private companies (Kati Farms and Nutreal) through a public-private partnership. The Principal Investigator is Dr. Jackson Efitre and his team will focus on scaling-up the use of improved, sustainable fish processing technologies such as the solar Tent dryers and raised racks to new communities across Uganda; enhancing market access and supply chain linkages for high-quality fish and fish products; as well as deepening women’s empowerment and strengthening the resilience of fishing communities through diversified income streams. The project is expected to run for September 2025- March 2028. The expected outcomes include: enhanced incomes and livelihoods for marginalized fishing groups, particularly women and youth; improved health and nutrition for vulnerable groups through diversification of fish products that are embedded in the market with strong supply chain linkages; sustainable fish processing and marketing models that can be scaled across Uganda and the East African region; improved women and youth participation in decision making and control of benefits in the SPF value chains; and improved socioeconomic conditions and ecosystem health through participatory, scalable approaches.
“Winning this competitive grant is an incredible opportunity for the team to solidify the achievements of the first phase as the funding enables us to move beyond research to embed these nutritional and technological solutions into the livelihoods of local communities,” said Dr. Efitre. “I am privileged to lead this impactful work on behalf of Makerere University. Scaling up these tested, climate-responsive technologies as well as empowering the women and youth will secure better nutrition and more sustainable livelihoods across fishing communities in Uganda.”
The project is set to be launched tomorrow, Tuesday, 28th October 2025 by the Acting Deputy Vice Chancellor, Finance and Administration and Principal, CoNAS, Prof. Winston Tumps Ireeta.
Please see below for details on the project.
Details on the previous project: https://news.mak.ac.ug/2023/03/nutrifish-project-registers-significant-achievements/
Agriculture & Environment
Ugandan Local Government Officials Trained on Environmental Valuation, Accounting, and Climate Resilience
Entebbe, Uganda – September 19, 2025
More than 20 local government officials from Kampala Capital City Authority (KCCA), Entebbe Municipality, and the districts of Wakiso, Mukono, and Mpigi have concluded a two-day intensive training on Environmental Valuation, Accounting, Evaluation, and Climate Change Mitigation and Adaptation.
Held at Central Inn Hotel in Entebbe from September 18–19, the workshop was organized by the Environment for Development (EfD) Makerere University Centre and funded by the Makerere University Research and Innovation Fund (Mak-RIF). The objective was to build local capacity in environmental governance and integrate natural capital and climate risks into local development planning.
The training was facilitated by Dr. Aisha Nanyiti, Dr. John Sseruyange, Dr. Peter Babyenda and Dr. Nick Kilimani- all from Makerere University.
Natural Resources Must Be Valued and Protected
Opening the workshop, Prof. Edward Bbaale, Director of the EfD-Mak Centre and Principal Investigator of the project, described the training as timely, given Uganda’s growing environmental and climate challenges.
“Uganda is already experiencing the adverse effects of climate variability—on agriculture, health, water resources, and the economy,” Prof. Bbaale noted. “This training empowers our environmental officers to use economic evidence to defend natural resources against competing land uses.”
He emphasized the need to monetize ecosystem services like wetlands, forests, and biodiversity to inform land-use decisions.
“A forest cleared for sugarcane may appear to create jobs, but when you account for its carbon sequestration, rainfall formation, and tourism potential, its long-term value far outweighs the short-term economic gains.”
Prof. Bbaale also urged that natural capital be included in Uganda’s national accounting systems to achieve sustainable and equitable development.
He thanked local government leadership for releasing their staff for the training and praised the collaboration between academia and government.
“You are not just trainees — you are future champions of environmental stewardship in your districts,” he told the participants.
Environmental Degradation Threatens Public Health
Representing the Chairperson of Mak-RIF, Dr. Sabrina Kitaka underscored the public health consequences of environmental degradation, linking it to disease outbreaks and natural disasters.
“We have just seen a 14-year-old girl in Lwengo contract Crimean-Congo hemorrhagic fever due to increased human-wildlife contact — a direct result of environmental encroachment,” Dr. Kitaka warned.
She connected rising flash floods, deforestation, and urban sprawl to poor environmental management and called for cross-sectoral awareness of environmental risks.
“This training is not just for environmentalists. Planners, economists, and health professionals must also be equipped with this knowledge,” she said.
Dr. Kitaka applauded the EfD-Mak team for using local experts, not foreign consultants, in delivering the training.
“We must train Ugandans to solve Uganda’s problems. That’s the spirit of Mak-RIF.”
She also revealed that the Government of Uganda has funded over 1,300 research projects through Mak-RIF over the last five years and called for continued investment in locally driven innovation.
“Like Oliver Twist, we ask for more. Science must be funded to help Ugandans solve Ugandan problems.”
Experts Present Practical Tools for Sustainable Planning
Localized Climate Action Is Urgent
Dr. Aisha Nanyiti urged participants to design district-specific climate policies, differentiating between mitigation (addressing the causes) and adaptation (responding to the impacts).
“Climate action begins at the local level. Districts must create context-appropriate bylaws and planning strategies to reduce vulnerability to floods, droughts, and other climate shocks.”
She emphasized that Uganda’s local governments are key to meeting national targets under NDP IV and Vision 2040, and that climate change must be addressed in all sectors — from health to urban planning.
Environmental Evaluation is a Safeguard
Dr. Sseruyange warned that development projects are at risk of failure if environmental assessments are not properly conducted.
“Roads, schools, and hospitals may be destroyed by floods or landslides if we ignore the environment. Planning must consider both the impact on nature and the reverse impact from degraded ecosystems.”
He called on local environmental officers to assert their roles in safeguarding both the environment and infrastructure investment.
“Neglecting environmental oversight may undo everything we build.”
What is Not Valued is Easily Destroyed
Dr. Peter Babyenda introduced participants to valuation tools like Contingent Valuation Method (CVM) and the Travel Cost Method, which help quantify the economic value of forests, wetlands, and biodiversity.
“These tools inform cost–benefit analysis, budgeting, and resource allocation. If we don’t value our natural assets, we risk losing them permanently.”
He stressed that environmental protection is not only an ecological issue, but also an economic, social, and political matter. He encouraged integration of valuation results into budgeting and planning under frameworks like the National Environment Act (2019).
Local Officials Call for Continued Engagement
Ibrahim Muwanguzi, Environmental Officer from Wakiso District, praised the training as a vital step toward mainstreaming environmental valuation into local and national development processes.
“Most government officials focus solely on economic returns, ignoring the critical but intangible value of natural resources,” he said.
He cited a recent case during Mpigi Expressway construction where a culturally significant tree sparked debate over its monetary value — from UGX 100,000 to UGX 100 million — due to lack of valuation standards.
“If services like flood control were quantified in shillings, it would help justify preservation of wetlands and forests,” he noted.
Muwanguzi also emphasized the need for environmental economists in government roles, urging stronger collaboration between academia and policy.
“We have graduates in natural resource economics. Let’s integrate them into our public service.”
Let This Not Be the Last
Tonny Mwidyeki, District Natural Resources Officer for Mpigi, delivered the vote of thanks on behalf of all trainees, emphasizing the long gap since the last such training.
“For many of us, it’s been years since we had a refresher like this. If we continue to have such sessions, we will serve our people and protect our environment better.”
He thanked the facilitators from Makerere University for the two-day sensitization and urged that such capacity-building workshops be held more regularly.
“From here, we go back not just informed, but ready to lead change.”
Time to Act is Now
Closing the training, Dr. Sseruyange, speaking on behalf of the EfD-Mak Director, reminded participants that environmental degradation has been decades in the making, and action must no longer be delayed.
“Development depends on the natural world. Let us act now — from our households to our districts — to reverse the damage and secure our future.”
He thanked the participants for their active engagement and promised continued collaboration between Makerere University, local governments, and national stakeholders to promote evidence-based environmental policy.
About EfD-Mak and Mak-RIF
The Environment for Development (EfD) Centre at Makerere University is part of a global network of research institutions focused on environmental economics, coordinated by the University of Gothenburg, Sweden.
The Makerere University Research and Innovation Fund (Mak-RIF) is a Government of Uganda-funded program supporting local research to address national development challenges. Since inception, Mak-RIF has supported over 1,300 research projects across disciplines.
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