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Bacterial community diversity and variation in spray water sources and the tomato fruit surface.

Telias A, White JR, Pahl DM, Ottesen AR, Walsh CS - BMC Microbiol. (2011)

Bottom Line: The two water sources tested had a significantly different bacterial composition.Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia.Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface.

View Article: PubMed Central - HTML - PubMed

Affiliation: Plant Science and Landscape Architecture Department, University of Maryland, College Park, MD 21201, USA. atelias@umd.edu

ABSTRACT

Background: Tomato (Solanum lycopersicum) consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water) when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production.

Results: The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant.

Conclusions: Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an important step forward towards the development of science-based metrics for Good Agricultural Practices.

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Related in: MedlinePlus

Hierarchical clustering of samples using the Jaccard index. Using shared OTU profiles across all samples, we computed Jaccard indices for clustering samples based on overall community similarity. Samples from each water environment cluster well, but even using OTU resolution, the fruit surface samples were not easily distinguishable.
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Figure 4: Hierarchical clustering of samples using the Jaccard index. Using shared OTU profiles across all samples, we computed Jaccard indices for clustering samples based on overall community similarity. Samples from each water environment cluster well, but even using OTU resolution, the fruit surface samples were not easily distinguishable.

Mentions: A hierarchical clustering of all samples was performed using the Jaccard index based on shared OTU composition (Figure 4). This tree indicated that the two fruit surface communities are not uniquely distinguishable at the OTU level despite the microbial differences in water sources. However, water samples did cluster with their associated environments.


Bacterial community diversity and variation in spray water sources and the tomato fruit surface.

Telias A, White JR, Pahl DM, Ottesen AR, Walsh CS - BMC Microbiol. (2011)

Hierarchical clustering of samples using the Jaccard index. Using shared OTU profiles across all samples, we computed Jaccard indices for clustering samples based on overall community similarity. Samples from each water environment cluster well, but even using OTU resolution, the fruit surface samples were not easily distinguishable.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108269&req=5

Figure 4: Hierarchical clustering of samples using the Jaccard index. Using shared OTU profiles across all samples, we computed Jaccard indices for clustering samples based on overall community similarity. Samples from each water environment cluster well, but even using OTU resolution, the fruit surface samples were not easily distinguishable.
Mentions: A hierarchical clustering of all samples was performed using the Jaccard index based on shared OTU composition (Figure 4). This tree indicated that the two fruit surface communities are not uniquely distinguishable at the OTU level despite the microbial differences in water sources. However, water samples did cluster with their associated environments.

Bottom Line: The two water sources tested had a significantly different bacterial composition.Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia.Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface.

View Article: PubMed Central - HTML - PubMed

Affiliation: Plant Science and Landscape Architecture Department, University of Maryland, College Park, MD 21201, USA. atelias@umd.edu

ABSTRACT

Background: Tomato (Solanum lycopersicum) consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water) when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production.

Results: The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant.

Conclusions: Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an important step forward towards the development of science-based metrics for Good Agricultural Practices.

Show MeSH
Related in: MedlinePlus