Systemic Colonization of Potato Plants by a Soilborne, Green Fluorescent Protein-Tagged Strain of Dickeya sp. Biovar 3

Abstract

Colonization of potato plants by soilborne, green fluorescent protein (GFP)-tagged Dickeya sp. IPO2254 was investigated by selective plating, epifluorescence stereo microscopy (ESM), and confocal laser scanning microscopy (CLSM). Replicated experiments were carried out in a greenhouse using plants with an intact root system and plants from which ca. 30% of the lateral roots was removed. One day after soil inoculation, adherence of the pathogen on the roots and the internal colonization of the plants were detected using ESM and CLSM of plant parts embedded in an agar medium. Fifteen days post-soil inoculation, Dickeya sp. was found on average inside 42% of the roots, 13% of the stems, and 13% of the stolons in plants with undamaged roots. At the same time-point, in plants with damaged roots, Dickeya sp. was found inside 50% of the roots, 25% of the stems, and 25% of the stolons. Thirty days postinoculation, some plants showed true blackleg symptoms. In roots, Dickeya sp. was detected in parenchyma cells of the cortex, both inter- and intracellularly. In stems, bacteria were found in xylem vessels and in protoxylem cells. Microscopical observations were confirmed by dilution spread-plating the plant extracts onto agar medium directly after harvest. The implications of infection from soilborne inoculum are discussed.

High-resolution metabolic mapping of cell types in plant roots

“…In other plant species, the prime location of pathogen or symbiotic bacterial infection of the root also occurs through the cortex as with the potato soil-borne pathogen Dickeya sp. IPO2254, which primarily infects root cortex cells (28). PPs, especially flavonols, which are also relatively highly accumulated in the cortex, provide protection from different biotic and abiotic stresses (29).…”

Salicylic acid can reduce infection symptoms caused by Dickeya solani in tissue culture grown potato (Solanum tuberosum L.) plants

“…Bacterial strains and media GFP-tagged D. solani IPO2222 (IPO2254) (Czajkowski et al 2010) . The experiment was repeated twice with the same set-up with two replicates for each experiment.…”

“…The results were averaged. Assessment of D. solani IPO2254 maceration ability on potato tuber slices upon treatment with SA A potato slice assay (Czajkowski et al 2010) was used to check if incubation of D. solani IPO2254 with SA prior to inoculation of potato tuber slices with the bacteria would affect its ability to macerate potato tuber tissue. For this, bacteria were grown for 12 h in TSB in the presence of 50 μM SA with agitation (200 rpm) at 28°C.…”

“…Pectobacterium and Dickeya spp. are vascular pathogens, able to infect potato tubers internally (Perombelon and Kelman 1980;Czajkowski et al 2009Czajkowski et al , 2010 and due to the ability of inhabiting the inner tuber tissues they will not be affected by the superficial treatments, thus the physical measures and chemical control agents will not effectively contribute to the control of Pectobacterium and Dickeya spp. in potato.…”

“…In replicated experiments the potato plants grown on medium supplemented with SA were investigated for the phytotoxic effects. In line with this, potato plants grown on a medium supplemented with SA and stem baseinoculated with GFP-tagged D. solani (Czajkowski et al 2010) were investigated for the blackleg development, bacterial population dynamics in stems and colonization of plant roots by the GFP-tagged bacteria.…”