Introduction and adaptation of an emerging pathogen to olive trees in Italy

• DOI: 10.1099/mgen.0.000735
• Publication Date: 2021-12-14T15:17:29Z
• Authors: Anne Sicard; Maria Saponari; Mathieu Vanhove; Andreina I. Castillo; Annalisa Giampetr...; Giuliana Loconsole; Pasquale Saldarelli; Donato Boscia; Claire Neema; Rodrigo P. P. Alm...
• Keywords: 0301 basic medicine; adaptation; highest posterior density; Xylella; 630; olive quick decline syndrome; environment/Symbiosis; emerging pathogen. Abbreviations: APL; 2.2 Factors relating to the physical environment; emerging pathogen; Aetiology; Research Articles; Phylogeny; [INFO.INFO-BI] Computer Science [cs]/Bioinformatics [q-bio.QM]; Xylella fastidiosa; 2. Zero hunger; 0303 health sciences; Genome; Apulia; Bacterial; High-Throughput Nucleotide Sequencing; Adaptation, Physiological; 3. Good health; ST53; population genomics, adaptation, Olive Quick Decline Syndrome; Phylogeography; Quick Decline Syndrome (OQDS); Italy; HPD; Infection; 570; Physiological; Olive Quick Decline Syndrome; Microbiology; OQDS; 03 medical and health sciences; Olea; Genetics; X. fastidiosa; Olive Quick Decline Syndrome (OQDS); Adaptation; Plant Diseases; outbreak; Whole Genome Sequencing; Human Genome; Central America; [SDV.EE.IEO] Life Sciences [q-bio]/Ecology, environment/Symbiosis; 15. Life on land; sequence type 53; [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology; Emerging Infectious Diseases; Good Health and Well Being; 13. Climate action; adaption; [SDV.EE.IEO]Life Sciences [q-bio]/Ecology; [INFO.INFO-BI]Computer Science [cs]/Bioinformatics [q-bio.QM]; [SDV.MP.BAC] Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology; Genome, Bacterial

The invasive plant pathogen

Xylella fastidiosa

currently threatens European flora through the loss of economically and culturally important host plants. This emerging vector-borne bacterium, native to the Americas, causes several important diseases in a wide range of plants including crops, ornamentals, and trees. Previously absent from Europe, and considered a quarantine pathogen,

X. fastidiosa

was first detected in Apulia, Italy in 2013 associated with a devastating disease of olive trees (Olive Quick Decline Syndrome, OQDS). OQDS has led to significant economic, environmental, cultural, as well as political crises. Although the biology of

X. fastidiosa

diseases have been studied for over a century, there is still no information on the determinants of specificity between bacterial genotypes and host plant species, which is particularly relevant today as

X. fastidiosa

is expanding in the naive European landscape. We analysed the genomes of 79

X

.

fastidiosa

samples from diseased olive trees across the affected area in Italy as well as genomes of the most genetically closely related strains from Central America. We provided insights into the ecological and evolutionary emergence of this pathogen in Italy. We first showed that the outbreak in Apulia is due to a single introduction from Central America that we estimated to have occurred in 2008 [95 % HPD: 1930–2016]. By using a combination of population genomic approaches and evolutionary genomics methods, we further identified a short list of genes that could play a major role in the adaptation of

X. fastidiosa

to this new environment. We finally provided experimental evidence for the adaptation of the strain to this new environment.