How Pseudomonas sp., Pectobacterium carotovorum and Ralstonia solanacearum strains isolated from the same host could be differentiated based on non-molecular methods (biochemical tests, culture mediums and etc.)?
Habibeh Hajian Maleki Briefly:
Pseudomonas - gram-neg (KON test), aerobic, blue-green fluorescent on King's B agar, LOPAT test will differentiate groups: Oxidase reaction negative = P. syringae pathovar or P. viridiflava, Potato soft-rot positive = P. viridiflava, Potato soft-rot negative = P. syringae pathovar, Most P. syringae pathovars = levan positive, P. viridiflava = levan negative, Oxidase reaction positive = P. marginalis, P. tolaasii, P. agarici, P. cichorii or non-pathogenic Pseudomonas (mostly P. fluorescence or P. putida).
Pectobacterium (and Dickeya): gram-neg (KON test), facultative anaerobic, on CVP agar - pit formation, potato slices + (pectolytic), Dickeya - blue pigment on NGM agar
Ralstonia - gram-neg (KON test), aerobic, Oxidase reaction positive, growth on SMSA, no pit formation on CVP, no blue-green pigment on King's B agar, no oxidative utilisation of glucose (Hugh-Leifson test), no growth on A1 agar (agrobacterium - selective), Arginine dihydrolase - negative.
Reference: Introduction to Practical Phytobacteriology A Manual for Phytobacteriology by SAFRINET, the Southern African (SADC) LOOP of
BioNET-INTERNATIONAL Compiled by T. Goszczynska, J.J. Serfontein & S. Serfontein. ARC – Plant Protection Research Institute
Pretoria, South Africa. 2000.
Thanks for your detailed and clear explanation*
When it comes to molecular methods, could these three genera be differentiated according to diagnostic PCR assay ( may be according to some primers designed for amplification of certain house keeping genes in each genus)?
Habibeh Hajian Maleki There are many primers published as genus-specific and designed based on 16S rRNA, 16S-23S ITS, or gyrB sequences, but, they often give positive PCR reaction with distantly related bacteria.
Some were reviewed in the work of Palacio-Bielsa, A., Cambra, M.A. and López, M.M., 2009. PCR detection and identification of plant-pathogenic bacteria: updated review of protocols (1989-2007). Journal of Plant Pathology, pp.249-297.
There are several genus-specific single-gene taxonomic targets for sequencing, they can generate trees congruent to larger MLST or WGS data sets. For example, citrate synthase (cts) for pseudomonads (see Berge, Odile, et al. "A user's guide to a data base of the diversity of Pseudomonas syringae and its application to classifying strains in this phylogenetic complex." PloS one 9.9 (2014): e105547.)
- Badges
- Science topic
- Similar topics
- Geoscience
- Cartography
- Mapping