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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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Bar chart of the area under the growth progress curves (AUGPC) calculated for Acidovorax citrulli (Ac), Clavibacter michiganensis subsp. michiganensis (Cmm), Pseudomonas syringae pv. tomato (Pst), Xanthomonas euvesicatoria (Xeu), Pseudomonas syringae pv. glycinea (Psg), and Serratia marcescens (Sm) populations on pepper (A), tomato (B), soybean (C), watermelon (D), and onion (E) seeds during 48 hour post inoculation (hpi).Bars indicate the mean AUDPC values and lines indicate the standard errors of the means. Treatments with different letters are significantly different according to Fisher's test of least significant difference (P<0.05).
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pone-0099215-g004: Bar chart of the area under the growth progress curves (AUGPC) calculated for Acidovorax citrulli (Ac), Clavibacter michiganensis subsp. michiganensis (Cmm), Pseudomonas syringae pv. tomato (Pst), Xanthomonas euvesicatoria (Xeu), Pseudomonas syringae pv. glycinea (Psg), and Serratia marcescens (Sm) populations on pepper (A), tomato (B), soybean (C), watermelon (D), and onion (E) seeds during 48 hour post inoculation (hpi).Bars indicate the mean AUDPC values and lines indicate the standard errors of the means. Treatments with different letters are significantly different according to Fisher's test of least significant difference (P<0.05).

Mentions: Target bacterial colonies were not recovered from any of the seed types which were inoculated with PBS. Seed germination percentages were not affected for the treated seeds as they were not significantly different from negative controls (P≥0.72). On pepper seeds, CFUs of X. euvesicatoria (2.5×107 CFU/flower), A. citrulli (6.2×107 CFU/flower), P. syringae pv. tomato (4.8×107 CFU/g), and P. syringae pv. glycinea (1.8×106 CFU/g) increased whereas populations of C. michiganensis subsp. michiganensis (3.8×105 CFU/g) and S. marcescens (2.7×105 CFU/g) remained 10 to 100 fold lower at 48 hpi (Fig 3A). In addition, X. euvesicatoria, A. citrulli, P. syringae pv. tomato, and P. syringae pv. glycinea displayed similar growth trends as their AUGPC values were not significantly different (P = 0.061); however, they were significantly higher than AUGPC values for C. michiganensis subsp. michiganensis and S. marcescens (P = 0.002) (Fig. 4A).


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)

Bar chart of the area under the growth progress curves (AUGPC) calculated for Acidovorax citrulli (Ac), Clavibacter michiganensis subsp. michiganensis (Cmm), Pseudomonas syringae pv. tomato (Pst), Xanthomonas euvesicatoria (Xeu), Pseudomonas syringae pv. glycinea (Psg), and Serratia marcescens (Sm) populations on pepper (A), tomato (B), soybean (C), watermelon (D), and onion (E) seeds during 48 hour post inoculation (hpi).Bars indicate the mean AUDPC values and lines indicate the standard errors of the means. Treatments with different letters are significantly different according to Fisher's test of least significant difference (P<0.05).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0099215-g004: Bar chart of the area under the growth progress curves (AUGPC) calculated for Acidovorax citrulli (Ac), Clavibacter michiganensis subsp. michiganensis (Cmm), Pseudomonas syringae pv. tomato (Pst), Xanthomonas euvesicatoria (Xeu), Pseudomonas syringae pv. glycinea (Psg), and Serratia marcescens (Sm) populations on pepper (A), tomato (B), soybean (C), watermelon (D), and onion (E) seeds during 48 hour post inoculation (hpi).Bars indicate the mean AUDPC values and lines indicate the standard errors of the means. Treatments with different letters are significantly different according to Fisher's test of least significant difference (P<0.05).
Mentions: Target bacterial colonies were not recovered from any of the seed types which were inoculated with PBS. Seed germination percentages were not affected for the treated seeds as they were not significantly different from negative controls (P≥0.72). On pepper seeds, CFUs of X. euvesicatoria (2.5×107 CFU/flower), A. citrulli (6.2×107 CFU/flower), P. syringae pv. tomato (4.8×107 CFU/g), and P. syringae pv. glycinea (1.8×106 CFU/g) increased whereas populations of C. michiganensis subsp. michiganensis (3.8×105 CFU/g) and S. marcescens (2.7×105 CFU/g) remained 10 to 100 fold lower at 48 hpi (Fig 3A). In addition, X. euvesicatoria, A. citrulli, P. syringae pv. tomato, and P. syringae pv. glycinea displayed similar growth trends as their AUGPC values were not significantly different (P = 0.061); however, they were significantly higher than AUGPC values for C. michiganensis subsp. michiganensis and S. marcescens (P = 0.002) (Fig. 4A).

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