Scientists develop effective tool for exploring the genetic diversity of the bacterial wilt pathogen in banana and enset in East and Central Africa
One of the diseases affecting banana in East and Central Africa and threatening the food and income of over 70 million people is Xanthomonas wilt (XW), a disease caused by the bacterium Xanthomonas vasicola pv. musacearum (Xvm).
The disease also attacks enset, an ancient false banana indigenous to Ethiopia, where it was first reported in the 1960s. The disease was first detected in banana in Uganda in the early 2000s and has since spread across neighboring countries, affecting all cultivated types of both crops.
Despite its economic impact on banana and enset production, little is known about the population biology and epidemiology of Xvm. It is very important in control efforts to understand the origin of the pathogen, decipher the evolutionary mechanisms leading to pathogen adaptation to new crops, and identify ecological factors (including the crop system composition) favoring this adaptation.
Therefore, scientists have developed a highly effective genotyping tool, the Multi Locus Variable Number of Tandem Repeat Analysis 19 scheme (MLVA-19) for unraveling the origin and pathways of emerging Xvm populations in East and Central African countries.
A total of 335 bacteria isolates were collected from DR Congo, Ethiopia, Kenya, Rwanda, Tanzania, and Uganda and confirmed to be Xvm using Xvm-specific primers subjected to the MLVA-19 scheme. The analysis showed that the MLVA-19 was discriminative enough to distinguish different haplotypes from country to field scales. The study also established that MLVA-19 can resolve the evolutionary patterns and invasion routes of this pathogen.
This genotyping tool is thus perfectly suited for exploring the genetic diversity of the Xvm populations in East and Central Africa and addressing evolutionary and ecological questions that are important for deciphering the epidemiology of Xanthomonas wilt on banana, including the reconstruction of Xvm invasion routes throughout Africa.
This tool can be further used in a transnational surveillance network to monitor the spread and evolution of XW throughout Africa and inform and guide the management of Xvm both in banana-based and enset-based cropping systems. It can also be used to assist the regional deployment of new Xvm-resistant banana and enset progenitors.
The study was conducted by IITA researchers in Uganda and Tanzania in collaboration with the Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics/Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa; UMP IPME, University of Montpellier, CIRAD, IRD, Montpellier, France; and CIRAD UMR BGPI, Montpellier, France.
The findings were published in the open-access article: “A new Multi Locus Variable Number of Tandem Repeat Analysis Scheme for epidemiological surveillance of Xanthomonas vasicola pv. musacearum, the plant pathogen causing bacterial wilt on banana and enset” found at: https://journals.plos.org/plosone/article/comments?id=10.1371/journal.pone.0215090
The study was funded by the BAXEPI project, supported by the Agropolis Foundation through the Investissements d’avenir program; the CGIAR Research Program on Roots, Tubers, and Banana (CRP-RTB); the COST Action CA16107 EuroXanth supported by COST (European Cooperation in Science and Technology); and the French Embassy in Uganda.