Michael Seeger: Genetic diversity of Clavibacter michiganensis subsp. michiganensis strains from Central Chile and their phylogenetic relationships with strains from America, Europe and Africa
- Datum: 15.07.2019
- Uhrzeit: 10:00 - 11:00
- Vortragende(r): Prof Michael Seeger von der Universidad Valparaiso, Chile
- Mehr Informationen über den Vortragenden finden Sie hier (auf Spanisch): https://www.departamentoquimica.usm.cl/academicos/michael-seeger/
- Ort: MPI Plön
- Raum: Hörsaal
- Gastgeber: Paul Rainey
Abstract (auf Englisch):
Bacterial canker
caused by Clavibacter michiganensis subsp. michiganensis
(Cmm) is one of the most important bacterial diseases of tomato.
In order to understand the emergence and dissemination of this
pathogen in Chile, Chilean Cmm strains isolated in the period
1996-2015 from different sites in Central Chile were
characterized and compared to a worldwide collection of strains.
Multilocus sequence analysis and typing (MLSA-MLST) based on
five housekeeping genes, and multilocus variable number of
tandem repeats (VNTR) analysis (MLVA) were used. Low diversity
was found using MLSA-MLST among the 25 Chilean strains, which
clustered into three groups, each corresponding to a single
sequence type (ST). Group I contained most strains (21/25),
whereas group II contained only one strain. These two groups
belonged to the same genetic lineage. Group III contained three
strains. MLVA also distributed the strains into the same three
groups. Group III strains shared the same ST as strains from
Europe, America and Africa. Group II strains shared the same ST
as strains from Brazil and Uruguay, while Group I strains shared
the same ST as two strains of unknown origin. Copper and
antibiotics (streptomycin, oxytetracycline and gentamicin) are
commonly used in Chile to control Cmm. A search of streptomycin
resistance-related genes was carried out using PCR and
sequencing techniques. MIC results showed that four strains were
highly sensitive to streptomycin, whereas 21 strains that
belongs to Group I were resistant. The mechanism conferring high
streptomycin resistance of these strains was elucidated. This
study shows that Cmm strains from Central Chile tend to be
clonal and have similar genetic profiles to strains from other
countries. By the other hand, the continuous use of streptomycin
leads to emergence of resistant Cmm strains, indicating that
novel alternatives to control this plant pathogen are required.