LAMP testing paves the way for better and rapid virus diagnostics in cassava and sweet potato seed in Tanzania

BLOG: Kwame Ogero, (CIP Tanzania) writes on capacity building efforts to boost LAMP usage

Cassava and sweet potato play a vital role in food security and income generation in Tanzania. However, production of these crops is highly hindered by viruses. Sweet potato virus disease (SPVD) caused by synergistic interaction between sweet potato feathery mottle virus (SPFMV) and sweet potato chlorotic stunt virus (SPCSV) is the most important disease of sweet potato in sub-Saharan Africa. Additionally, cassava production is highly constrained by cassava brown streak disease (CBSD). CBSD is caused by cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV).

Clean seed programs through which farmers can access quality planting material that has been tested as virus-free can help mitigate the effects associated with the viruses. Tanzania has already gazetted seed regulations that guide production of certified seed. The regulations require testing of pre-basic seed for presence of viruses. However, current diagnostic tests are either not sensitive enough or require expensive laboratory equipment and a high level of experience to perform.

To address this challenge, scientists have started optimizing the use of loop-mediated isothermal amplification (LAMP) in diagnosis of cassava and sweetpotato viruses. The technology is gaining popularity in plant health diagnostics because of its time efficiency and cost effectiveness. It can be used in field conditions therefore making it ideal for use within seed quality assurance schemes by regulatory bodies.

Working with IITA, CIP is building the capacities of seed regulators from the Tanzania Official Seed Certification Institute (TOSCI) to use LAMP. Successful adoption of LAMP by the regulators needs harmonizing the testing procedures for the two crops.

Capacity building and protocol harmonization have already started with support from ISSD Africa, the Sweetpotato Genetic Advances and Innovative Seed Systems (SweetGAINS) and Building an Economically-Sustainable Seed System in Tanzania for Cassava (BEST) projects. In April 2021 key staff from CIP and IITA were trained as ‘trainer of trainers’ with assistance from Bramwel Wanjala of the Kenya Agricultural and Livestock Research Organization (KALRO).

Photo 1: Veneranda Ngazi from the International Institute for Tropical Agriculture loads samples into a Genie II LAMP machine during an on-site virus testing in Dar es Salaam, Tanzania in April 2021. (Photo credit: K. Ogero/CIP)

The trained staff then conducted a training for TOSCI pathology staff in September 2021. Eleven TOSCI staff were trained. The trainees comprised of eight staff from TOSCI headquarters in Morogoro and one each from Mwanza, Mtwara and Njombe zonal offices. This was important because it will contribute towards decentralization of the technology.

Photo 2: Participants of the LAMP training held at TOSCI headquarters in September 2021. Photo credit: K. Ogero/CIP.

Overall, the added skills will enable the Tanzanian government to enhance the quality of its seed systems for sweetpotato and cassava while lowering the administrative costs for future seed businesses to earn certification for seed production. In addition to the training IITA donated one LAMP machine for use at TOSCI headquarters.

Photo 3: Veneranda Ngazi of IITA handing over a LAMP machine (Genie III) to Salehe Kombo of TOSCI. Photo credit: K. Ogero/CIP