‘Candidatus Liberibacter solanacearum’ is a α-Proteo
bacteria, Gram-negative, restricted to plant phloem and to the
haemolymph of psyllids that act as vectors. This emerging
bacterium has been associated with different diseases in different
hosts and associated with carrot (Daucus carota) in Spain.
Vegetative disorders of unknown etiology have also been observed
in celery (Apium graveolens) since 2008.
A real-time PCR protocol specific to ‘Ca. L. solanacearum’
detection, using TaqMan probe and direct sample preparation
methods have been developed. This technology has been validated
in an intra-laboratory study (sensitivity 1, specificity 1 and accuracy
100%) and is available commercially as a complete kit. It has been
demonstrated that ‘Ca. L. solanacearum’ is associated with the
observed syndrome in celery and a new bacterium haplotype (E)
has been identified. With these results it is concluded that celery is a
new host of ‘Ca. L. solanacearum’ (Teresani et al., 2014a).
Using the newly developed real-time PCR protocol ‘Ca. L.
solanacearum’ has been detected in 42,6% of the carrot seeds lots
tested and in individual seeds. The number of cells/seeds has been
estimated in 4.8±3.3 to 210±6.7, which only 5% were viable. After
150 days post-germination, 12% of seedlings showed symptoms
and tested positive for ‘Ca. L. solanacearum’. Liberibacter-like cells
were observed in the phloem sieve elements of the seed coat and in
the phloem of carrot leaf midrib from seedlings. These results demonstrated that ‘Ca. L. solanacearum’ is transmitted by carrot
seeds (Bertolini et al., 2014b).
The collected arthropods were classified into families, and
the superfamily Psylloidea was identified to the species level
resulting Bactericera trigonica, B. tremblayi and B. nigricornis the
main identified species. The population dynamics of different
psyllids species visiting carrot, celery and potato has been
determined, concluding that the highest populations are captured
during summer. The bacterium has been detected in the different
Bactericera species previous cited additionally to Bactericera sp.
The psyllid species carrying the bacteria can be considered as
possible vectors of the bacterium (Teresani et al. 2014b).
Electrical Penetration Graphs showed that B. trigonica was
able to feed in the phloem of carrot, celery and potato but not in the
phloem of tomato plants. Experimental transmission showed that B.
trigonica transmitted ‘Ca. L. solanacearum’ from carrot to carrot,
celery, potato and tomato. More efficient transmission occurred
with ten individuals, and the transmission rates were 100% in
celery, 80% in carrot and 10% in potato and tomato. The
experimental transmission to potatoes threatens this crop (Teresani
et al., 2014c).
These combined results have built a scientific foundation of
the biological and epidemiological aspects of ‘Ca. L. solanacearum’
contributing to new scientific information that is key in cultivation
of celery and carrot to establish bacteria control strategies. The use of bacteria-free carrot seed lots will definitely contribute to mitigate
damage and reduce risks of transmission to solanaceous crops. / Ribeiro Teresani, G. (2014). Candidatus Liberibacter solanacearum: detection, characterization, new hosts and epidemiology in Spain [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48459 / TESIS
| Identifer | oai:union.ndltd.org:upv.es/oai:riunet.upv.es:10251/48459 |
| Date | 11 December 2015 |
| Creators | Ribeiro Teresani, Gabriela |
| Contributors | Bertolini, Edson, Cambra Alvarez, Mariano J., Lopez Gonzalez, Maria Milagros, Universitat Politècnica de València. Departamento de Producción Vegetal - Departament de Producció Vegetal |
| Publisher | Universitat Politècnica de València |
| Source Sets | Universitat Politècnica de València |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:eu-repo/semantics/acceptedVersion |
| Rights | http://rightsstatements.org/vocab/InC/1.0/, info:eu-repo/semantics/openAccess |
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