| Summary: | Bacterial burn is one of the major diseases affecting pear trees worldwide, with serious impacts on producers and economy. In Morocco, several pear trees (<i>Pyrus communis</i>) have shown leaf burns since 2015. To characterize the causal agent of this disease, we isolated fourteen bacterial strains from different parts of symptomatic pear trees (leaves, shoots, fruits and flowers) that were tested <i>in planta</i> for their pathogenicity on Louise bonne and Williams cultivars. The results showed necrotic lesions with a significant severity range from 47.63 to 57.77% on leaves of the Louise bonne cultivar inoculated with isolate B10, while the other bacterial isolates did not induce any disease symptom. 16S rRNA gene sequencing did not allow robust taxonomic discrimination of the incriminated isolate. Thus, we conducted whole-genome sequencing (WGS) and phylogenetic analyzes based on <i>gyrA</i>, <i>gyrB</i> and <i>cdaA</i> gene sequences, indicating that this isolate belongs to the <i>Bacillus altitudinis</i> species. This taxonomic classification was further confirmed by the Average Nucleotide Identity (ANI) and the <i>in silico</i> DNA-DNA hybridization (<i>is</i>DDH) analyzes compared to sixty-five <i>Bacillus</i> spp. type strains. The genome was mined for genes encoding carbohydrate-active enzymes (CAZymes) known to play a role in the vegetal tissue degradation. 177 candidates with functions that may support the <i>in planta</i> phytopathogenicity results were identified. To the best of our knowledge, this is the first data reporting <i>B. altitudinis</i> as agent of leaf burn in <i>P. communis</i> in Morocco. Our dataset will improve our knowledge on spread and pathogenicity of <i>B. altitudinis</i> genotypes that appears as emergent phytopathogenic agent, unveiling virulence factors and their genomic location (i.e., within genomic islands or the accessory genome) to induce trees disease.
|
|---|
