Fast tracking of certified seed potato through improved diagnosis of bacterial wilt using Field Deployable LAMP Assay

Bacterial wilt, caused by Ralstonia solanacearum speciescomplex (RSSC), is an old but serious bioticconstraint and one of the most significant limitations to clean potato seed production, an essential component of high yields in many countries in Sub Saharan Africa. It has resulted in 30-100% potato yield losses putting a huge dent on food security and livelihoods of many smallholder farmers. 






Potato plants showing wilting symptoms in the field and bacteria oozing from potato eyes

In many countries, seed potato certification standards have zero tolerance for bacterial wilt pathogen and can lead to rejection of an entire potato field for seed. This therefore puts certified seed potato production that currently barely meets 2% of total area planted with potato at a high risk. There are a few seed merchants that produce certified seed potato and increasing quantities of certified seed is a major priority to improve yields and meet the increasing food demands. In Kenya, the International Potato Center (CIP) in collaboration with the Kenya Plant Health Inspectorate Service (KEPHIS) validated the cost-effective field deployable LAMP (Loop-mediated Isothermal Amplification) assay for the detection of Ralstonia from stem, leaf, tuber and soil. This will speed up the seed inspection and certification process.

To this end, through the support from GIZ-BMZ funded project on “Improved Diagnostics and genetic/molecular diversity of Ralstonia from Kenya and Uganda” CIP and KEPHIS conducted a two day training aimed at capacity building of East African countries’ seed regulatory and phytosanitary authorities as well as private diagnostic clinic personnel on the use of “field deployable LAMP assay to detect Ralstonia from stem, tuber and soil sample. The training held at KEPHIS Plant Quarantine and Bio-safety 

 

 

 

 

Phytosanitary authorities and private diagnostic clinic personnel from Kenya, Uganda, Tanzania, Malawi, Ethiopia and Rwanda after hands on training on field deployable LAMP assay at Plant Quarantine and Bio-safety station

The trainees got hands-on training on how to detect Ralstonia from stem, tuber and soil where they participated in extraction, preparation and testing samples using the LAMP assay. They were also taken through the assay validation process where they were shown sigmoid curves that show positive tests for Ralstonia.  Trainees were impressed with the technology as it requires fewer reagents, simple laboratory skills and expertise, and helps in making informed and fast decisions on whether to accept or reject potato seed in the field. They also appreciated the use of the technique as it is specific and suggested adoption and use during inspections, surveillance and at border points. They added that, other protocols for diagnosis of various diseases in different plants should be developed.