Origins of citrus greening in Martinique, La Réunion and Guadeloupe disentangled

Citrus greening (huanglongbing) is the most important threat to citrus worldwide. Of the 3 species of the causal bacteria, “Candidatus Liberibacter asiaticus” is the most widespread whereas “Ca. americanus” and “Ca. Liberibacter africanus” have a more restricted geographic distribution and are sensitive to high temperatures. Symptoms of citrus greening were first observed on La Réunion island in 1968 and then about 30-40 years later in Guadeloupe and Martinique. Disease management requires knowledge of the relative importance of local spread vs. importation for disease spread. By characterizing genetic profiles of bacterial strains from these islands, a team of BEYOND scientists in La Réunion and Montpellier have shown that the epidemics are indeed caused mostly by “Ca. Liberibacter asiaticus. Furthermore, they revealed that current epidemics in La Réunion are likely to be caused by strains re-emerging from local infections from the past decades. In contrast, epidemics in Martinique and Guadeloupe are likely to be caused by bacteria that originate from a single introduction - very distinct from the bacteria in La Réunion - that has moved between the two islands.

Publication: Genetic signatures of contrasted outbreak histories of “Candidatus Liberibacter asiaticus”, the bacterium that causes citrus Huanglongbing, in three outermost regions of the European Union.

More news coverage: Histoire de l’émergence de la maladie du Huanglongbing dans trois régions ultrapériphériques de l’Union Européenne