BIOTECHNOLOGY

Uganda is a country well-endowed with significant natural resources, including ample fertile land, regular rainfall, and mineral deposits. The economy is basically agricultural, and it occupies 80% of the working population.  

However, banana production in Uganda is constrained by a complex of problems such as reduced soil fertility, poor agronomy practices, inferior varieties, drought, socio-economic problems and biotic factors like banana weevils, nematodes, black sigatoka, banana bacterial wilt and fusarium wilt.

Due to the declining productivity, Uganda has adopted biotechnological approaches to complement already existing conventional methods to address constraints to crop improvement and agricultural productivity.

Image (below) of a Confield Field Trial (CFT) located at the National Agricultural Research Laboratories (NARL) in Kawanda - Wakiso District.

This project is using novel approaches to the improvement of banana production in Eastern Africa - the application of biotechnological methodologies.

The Project utilises a modified cysteine proteinase inhibitor from papaya, Carica papaya L. (CpCYSΔ89 or Cyst) and Bacillus thuringiensis crystalline protein (Bt.Crystal6A or Cry6A) to develop transgenic bananas with resistance to weevils and nematodes. Project has also isolated resistance genes to protect dessert bananas against Foc race 1.

Objectives;

• To evaluate and release nematode and weevil resistant banana products and a tracking system.
• To generate new technologies (genes) for Foc resistance and develop resistant dessert bananas.

Progress
Having established transgenic plants in the confined field trial (CFT), the Project has undertaken maintenance of these plants under field conditions. Including:

• Maintain the plants under field conditions in the CFT,
• Collect and establish weevil damage data in the established field plants,
• Collect and establish nematode population damage data in established field,
• Collect agronomic and yield data,
• Inspection of CFT facilities by National Biosafety Committee and present progress report and
• Molecular characterisation (PCR) - resistant lines.

Additionally, this Project aims to address Foc race 1 resistance in dessert bananas through over-expression of resistance genes from selected banana germplasm. This will be achieved by isolating and cloning Foc race 1 resistance genes through (i) In-vitro multiplication of resistant genotypes, (ii) Foc inoculation of resistant genotypes to induce target genes, (iv) Extract total RNA and genomic DNA, (v) cDNA synthesis and RT-PCR of target genes, (vii) Clone, sequence and analyse target genes, and (viii) Build binary transformation vectors.

NARO in collaboration with partners, has also been conducting research aimed at contributing to food security and improving livelihoods of small holder farmers in Uganda by generating and promoting transgenic resistant cooking banana varieties for the control of the devastating Banana Xanthomonas wilt (BXW) disease under the authorisation of NBC decision NBC/01/2016 and permit number A529.

Under this permit, NARO’s National Banana Research Programme was authorised to conduct multi- location Confined Field Trials (CFTs) of transgenic banana cultivars (Matooke Hybrid M9 and Musa AAA-EA banana cv Nakitembe) to evaluate stability of transgenic resistance against banana BXW.

Image (below): A team from the National Biosafety Committee (NBC) inspecting the BXW CFT field at Kawanda in 2021.

The project is at event selection stage of confined field trial at NARL-Kawanda (Wakiso district). The long-term control of BXW through Host Resistance is conducted through Genetic Engineering, by utilising potential resistance genes (HRAP and PFLP) from sweet pepper.

The objectives of the CFT are to:

1. To characterise transgenic lines by molecular analytical methods.
2. To challenge transgenic lines with BXW under field conditions and select resistant lines.
3. Collect sufficient data to use to select transgenic lines resistant to BXW. These shall include plant growth and yield parameters such as yield, maturity period, stem, leaf and fruit characteristics, incidences and severity of pests and diseases. Resistant lines will be advanced to multi-locational confined field trials (ML-CFTs).

Research activities:

• Cell culture _ Initiation and maintenance of cell suspensions
• Transformation of E.coli and Agrobacterium
• Transformation of cell suspensions and regeneration of transgenic bananas
• Molecular analysis - PCR, Southern blot analysis, etc.
• Testing of the transgenic plants in screen house conditions
• Testing transgenic plants in the CFT