Banana Fusarium wilt, also named Panama disease, has been a food security challenge for decades, threatening the sustainable production of the banana (Musa spp.) crop. This disease is caused by the haploid ascomycete fungus Fusarium oxysporum f. sp. cubense (Foc). Foc is asexual but very polymorphic, composed of 39 Vegetative Compatibility Groups (VCGs) distributed in 3 clades (A, B, C) and 8 clusters; 3 races (race 1, 2, 4) were defined according to host range on banana. Since its first description in Australia (1876) this disease has spread around the world, causing in the early 1950s the replacement of the cultivar Gros Michel (susceptible to race 1) by the Cavendish group in export banana plantations.

The sustainability of the Cavendish has been recently threatened by the emergence of the "Tropical Race 4" or TR4, pathogenic on the main banana-dessert types.

The expansion of TR4 followed three phases: (i) its report in Taiwan in 1967 and the first epidemics (Indonesia, Malaysia, Australia) in the 1990s, (ii) its appearance in China (1996-2010) and in the Philippines (2000-2008), (iii) its “exit from Asia” from 2011 (Middle East, India and Pakistan, Mozambique, South America, Turkey). The contrast is striking between the “Asian phase” of the disease, which has been confined to Southeast Asia for more than 20 years, and its “global phase”, characterized by a succession of contemporary epidemics on several continents. We hypothesize that this sudden acceleration of the expansion of TR4 is not only linked to the globalization of exchanges, but also to genotypic changes. It is therefore particularly important to understand the molecular and evolutionary bases of this runaway.

Thanks to a collaboration with a leading team in Stellenbosch University (South Africa), we sequenced genomes of a worldwide collection of TR4 isolates collected over a 32 year-range.  We then used a population genomics approach to reconstruct the main TR4 invasion routes around the world, and better understand the evolutionary history of this major emergence for the sustainability of the banana crop.  The first results and future prospects of this project will be presented and detailed during this seminar