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Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

Dutta B, Gitaitis R, Smith S, Langston D - PLoS ONE (2014)

Bottom Line: The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67).The percentage of seedlots infested with -interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03).None of the seedlots with incompatible/-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology, University of Georgia, Coastal Plain Experiment Station, Tifton, Georgia, United States of America.

ABSTRACT
The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a -interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6) colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with -interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and -interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized by compatible/incompatible/-interacting bacteria to higher populations; however, the level of colonization differed significantly depending on the type of bacterial species used.

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Temporal dynamics of Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, Pseudomonas syringae pv. glycinea, and Serratia marcescens populations on pepper (A), tomato (B), soybean (C), and watermelon (D) flowers during 96 hour post inoculation (hpi).Three flowers per host/non-host-bacterial species combinations were sampled at 0, 6, 12, 24, 48, 96 hpi and populations of respective bacterial species were enumerated on semi-selective media. Data points represent the mean bacterial populations at each sampling period in two independent experiments. Bars indicate the standard error of the mean.
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pone-0099215-g001: Temporal dynamics of Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, Pseudomonas syringae pv. glycinea, and Serratia marcescens populations on pepper (A), tomato (B), soybean (C), and watermelon (D) flowers during 96 hour post inoculation (hpi).Three flowers per host/non-host-bacterial species combinations were sampled at 0, 6, 12, 24, 48, 96 hpi and populations of respective bacterial species were enumerated on semi-selective media. Data points represent the mean bacterial populations at each sampling period in two independent experiments. Bars indicate the standard error of the mean.

Mentions: Target bacterial species were not recovered from the flowers (all tested plant species) whose stigmas were treated with PBS. On pepper flowers, the populations of P. syringae pv. glycinea (2.8×107 CFU/flower), A. citrulli (5.7×107 CFU/flower), P. syringae pv. tomato (7.2×106 CFU/flower), and S. marcescens (3.7×106 CFU/flower) increased exponentially by 96 hpi (Fig.1A). In contrast, during the same period, populations of X. euvesicatoria (2.5×105 CFU/flower) and C. michiganensis subsp. michiganensis (6.2×105 CFU/ blossom) increased to populations that were 10 to 100 fold lower than other tested bacterial species (Fig. 1A). Based on AUGPC values, significant differences were not observed among P. syringae pv. glycinea, A. citrulli, P. syringae pv. tomato, and S. marcescens strains (P = 0.271), respectively for their ability to colonize pepper blossoms (Fig. 2A). In contrast, AUGPC values for X. euvesicatoria and C. michiganensis subsp. michiganensis were significantly lower than A. citrulli and P. syringae pv. glycinea (P≤0.006) (Fig. 2A). However, the significant differences were not observed among X. euvesicatoria, C. michiganensis subsp. michiganensis, P. syringae pv. tomato, and S. marcescens (Fig. 2A).


Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

Dutta B, Gitaitis R, Smith S, Langston D - PLoS ONE (2014)

Temporal dynamics of Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, Pseudomonas syringae pv. glycinea, and Serratia marcescens populations on pepper (A), tomato (B), soybean (C), and watermelon (D) flowers during 96 hour post inoculation (hpi).Three flowers per host/non-host-bacterial species combinations were sampled at 0, 6, 12, 24, 48, 96 hpi and populations of respective bacterial species were enumerated on semi-selective media. Data points represent the mean bacterial populations at each sampling period in two independent experiments. Bars indicate the standard error of the mean.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061015&req=5

pone-0099215-g001: Temporal dynamics of Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, Pseudomonas syringae pv. glycinea, and Serratia marcescens populations on pepper (A), tomato (B), soybean (C), and watermelon (D) flowers during 96 hour post inoculation (hpi).Three flowers per host/non-host-bacterial species combinations were sampled at 0, 6, 12, 24, 48, 96 hpi and populations of respective bacterial species were enumerated on semi-selective media. Data points represent the mean bacterial populations at each sampling period in two independent experiments. Bars indicate the standard error of the mean.
Mentions: Target bacterial species were not recovered from the flowers (all tested plant species) whose stigmas were treated with PBS. On pepper flowers, the populations of P. syringae pv. glycinea (2.8×107 CFU/flower), A. citrulli (5.7×107 CFU/flower), P. syringae pv. tomato (7.2×106 CFU/flower), and S. marcescens (3.7×106 CFU/flower) increased exponentially by 96 hpi (Fig.1A). In contrast, during the same period, populations of X. euvesicatoria (2.5×105 CFU/flower) and C. michiganensis subsp. michiganensis (6.2×105 CFU/ blossom) increased to populations that were 10 to 100 fold lower than other tested bacterial species (Fig. 1A). Based on AUGPC values, significant differences were not observed among P. syringae pv. glycinea, A. citrulli, P. syringae pv. tomato, and S. marcescens strains (P = 0.271), respectively for their ability to colonize pepper blossoms (Fig. 2A). In contrast, AUGPC values for X. euvesicatoria and C. michiganensis subsp. michiganensis were significantly lower than A. citrulli and P. syringae pv. glycinea (P≤0.006) (Fig. 2A). However, the significant differences were not observed among X. euvesicatoria, C. michiganensis subsp. michiganensis, P. syringae pv. tomato, and S. marcescens (Fig. 2A).

Bottom Line: The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67).The percentage of seedlots infested with -interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03).None of the seedlots with incompatible/-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology, University of Georgia, Coastal Plain Experiment Station, Tifton, Georgia, United States of America.

ABSTRACT
The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a -interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6) colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with -interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and -interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized by compatible/incompatible/-interacting bacteria to higher populations; however, the level of colonization differed significantly depending on the type of bacterial species used.

Show MeSH
Related in: MedlinePlus