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A Carotenoid-Deficient Mutant in Pantoea sp. YR343, a Bacteria Isolated from the Rhizosphere of Populus deltoides, Is Defective in Root Colonization.

Bible AN, Fletcher SJ, Pelletier DA, Schadt CW, Jawdy SS, Weston DJ, Engle NL, Tschaplinski T, Masyuko R, Polisetti S, Bohn PW, Coutinho TA, Doktycz MJ, Morrell-Falvey JL - Front Microbiol (2016)

Bottom Line: The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host.Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots.YR343.

View Article: PubMed Central - PubMed

Affiliation: Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA.

ABSTRACT
The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host. A better understanding of the microbial mechanisms that promote plant health and stress tolerance will enable strategies for improving the productivity of economically important plants. Pantoea sp. YR343 is a motile, rod-shaped bacterium isolated from the roots of Populus deltoides that possesses the ability to solubilize phosphate and produce the phytohormone indole-3-acetic acid (IAA). Pantoea sp. YR343 readily colonizes plant roots and does not appear to be pathogenic when applied to the leaves or roots of selected plant hosts. To better understand the molecular mechanisms involved in plant association and rhizosphere survival by Pantoea sp. YR343, we constructed a mutant in which the crtB gene encoding phytoene synthase was deleted. Phytoene synthase is responsible for converting geranylgeranyl pyrophosphate to phytoene, an important precursor to the production of carotenoids. As predicted, the ΔcrtB mutant is defective in carotenoid production, and shows increased sensitivity to oxidative stress. Moreover, we find that the ΔcrtB mutant is impaired in biofilm formation and production of IAA. Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots. Taken together, these data suggest that carotenoids are important for plant association and/or rhizosphere survival in Pantoea sp. YR343.

No MeSH data available.


Related in: MedlinePlus

Phenotypic characteristics of Pantoea sp. YR343. (A) Growth of wild type Pantoea sp. YR343 grown in liquid LB, R2A, and M9 media. (B) Phosphate solubilization by Pantoea sp. YR343 is shown by a zone of clearing surrounding the colony. (C) Colony morphology of Pantoea sp. YR343 on LB (top) versus R2A (bottom) agar plates. (D) Bright field image of Pantoea sp. YR343 grown in R2A medium (left). (Right) Cellulose production in Pantoea sp. YR343 biofilm as detected by Calcofluor White staining (blue). The distribution of cells is indicated by staining with Syto61 (red). (E) Swimming and swarming motility of Pantoea sp. YR343. Swimming motility was characterized using LB medium with 0.3% agar (left) and swarming motility was characterized on LB medium with 0.6% agar, or on LB medium with 0.6% agar supplemented with 0.4% glucose or glycerol (right).
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Figure 2: Phenotypic characteristics of Pantoea sp. YR343. (A) Growth of wild type Pantoea sp. YR343 grown in liquid LB, R2A, and M9 media. (B) Phosphate solubilization by Pantoea sp. YR343 is shown by a zone of clearing surrounding the colony. (C) Colony morphology of Pantoea sp. YR343 on LB (top) versus R2A (bottom) agar plates. (D) Bright field image of Pantoea sp. YR343 grown in R2A medium (left). (Right) Cellulose production in Pantoea sp. YR343 biofilm as detected by Calcofluor White staining (blue). The distribution of cells is indicated by staining with Syto61 (red). (E) Swimming and swarming motility of Pantoea sp. YR343. Swimming motility was characterized using LB medium with 0.3% agar (left) and swarming motility was characterized on LB medium with 0.6% agar, or on LB medium with 0.6% agar supplemented with 0.4% glucose or glycerol (right).

Mentions: As determined by phylogenetic analysis, Pantoea sp. YR343 is a member of the Enterobacteriaceae family and falls into the class of γ-proteobacteria. Pantoea sp. YR343 is a Gram-negative bacterium that grows in liquid LB, R2A, or M9 minimal medium using glucose as a carbon source (Figure 2A). When grown on medium containing an insoluble form of calcium phosphate, a zone of clearing formed around colonies of Pantoea sp. YR343, indicating that this species is capable of phosphate solubilization (Figure 2B). Pantoea sp. YR343 growing on LB agar plates produced colonies that were round, smooth, and produced a yellow pigment (Figure 2C). In contrast, Pantoea sp. YR343 produced colonies that were irregularly shaped, wrinkly, and light yellow in color when grown on R2A agar plates (Figure 2C). Pantoea sp. YR343 also appeared to be highly mucoid, particularly when grown on R2A medium. Microscopic observation showed that Pantoea sp. YR343 displays a rod-shaped morphology with cells averaging approximately 2 μm in length (Figure 2D). In addition, Pantoea sp. YR343 was able to form biofilms on abiotic surfaces and the production of cellulose was detected in these biofilms by staining with Calcofluor White (Figure 2D). We also analyzed motility behavior in this organism using LB medium containing either 0.3% (swimming) or 0.6% (swarming) agar (Figure 2E). After 18 h, the cells had moved from the center to the edges of the plate, consistent with swimming motility behavior. Swarming motility was also observed, particularly when Pantoea sp. YR343 was grown on LB supplemented with 0.4% glycerol (Figure 2E). Finally, we used GC-MS analyses to examine whether Pantoea sp. YR343 could produce IAA, which is synthesized from the amino acid tryptophan (Patten and Glick, 1996). The tryptophan-dependent production of IAA was confirmed by GC-MS analyses and measured at approximately 0.5 μg/ml.


A Carotenoid-Deficient Mutant in Pantoea sp. YR343, a Bacteria Isolated from the Rhizosphere of Populus deltoides, Is Defective in Root Colonization.

Bible AN, Fletcher SJ, Pelletier DA, Schadt CW, Jawdy SS, Weston DJ, Engle NL, Tschaplinski T, Masyuko R, Polisetti S, Bohn PW, Coutinho TA, Doktycz MJ, Morrell-Falvey JL - Front Microbiol (2016)

Phenotypic characteristics of Pantoea sp. YR343. (A) Growth of wild type Pantoea sp. YR343 grown in liquid LB, R2A, and M9 media. (B) Phosphate solubilization by Pantoea sp. YR343 is shown by a zone of clearing surrounding the colony. (C) Colony morphology of Pantoea sp. YR343 on LB (top) versus R2A (bottom) agar plates. (D) Bright field image of Pantoea sp. YR343 grown in R2A medium (left). (Right) Cellulose production in Pantoea sp. YR343 biofilm as detected by Calcofluor White staining (blue). The distribution of cells is indicated by staining with Syto61 (red). (E) Swimming and swarming motility of Pantoea sp. YR343. Swimming motility was characterized using LB medium with 0.3% agar (left) and swarming motility was characterized on LB medium with 0.6% agar, or on LB medium with 0.6% agar supplemented with 0.4% glucose or glycerol (right).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4834302&req=5

Figure 2: Phenotypic characteristics of Pantoea sp. YR343. (A) Growth of wild type Pantoea sp. YR343 grown in liquid LB, R2A, and M9 media. (B) Phosphate solubilization by Pantoea sp. YR343 is shown by a zone of clearing surrounding the colony. (C) Colony morphology of Pantoea sp. YR343 on LB (top) versus R2A (bottom) agar plates. (D) Bright field image of Pantoea sp. YR343 grown in R2A medium (left). (Right) Cellulose production in Pantoea sp. YR343 biofilm as detected by Calcofluor White staining (blue). The distribution of cells is indicated by staining with Syto61 (red). (E) Swimming and swarming motility of Pantoea sp. YR343. Swimming motility was characterized using LB medium with 0.3% agar (left) and swarming motility was characterized on LB medium with 0.6% agar, or on LB medium with 0.6% agar supplemented with 0.4% glucose or glycerol (right).
Mentions: As determined by phylogenetic analysis, Pantoea sp. YR343 is a member of the Enterobacteriaceae family and falls into the class of γ-proteobacteria. Pantoea sp. YR343 is a Gram-negative bacterium that grows in liquid LB, R2A, or M9 minimal medium using glucose as a carbon source (Figure 2A). When grown on medium containing an insoluble form of calcium phosphate, a zone of clearing formed around colonies of Pantoea sp. YR343, indicating that this species is capable of phosphate solubilization (Figure 2B). Pantoea sp. YR343 growing on LB agar plates produced colonies that were round, smooth, and produced a yellow pigment (Figure 2C). In contrast, Pantoea sp. YR343 produced colonies that were irregularly shaped, wrinkly, and light yellow in color when grown on R2A agar plates (Figure 2C). Pantoea sp. YR343 also appeared to be highly mucoid, particularly when grown on R2A medium. Microscopic observation showed that Pantoea sp. YR343 displays a rod-shaped morphology with cells averaging approximately 2 μm in length (Figure 2D). In addition, Pantoea sp. YR343 was able to form biofilms on abiotic surfaces and the production of cellulose was detected in these biofilms by staining with Calcofluor White (Figure 2D). We also analyzed motility behavior in this organism using LB medium containing either 0.3% (swimming) or 0.6% (swarming) agar (Figure 2E). After 18 h, the cells had moved from the center to the edges of the plate, consistent with swimming motility behavior. Swarming motility was also observed, particularly when Pantoea sp. YR343 was grown on LB supplemented with 0.4% glycerol (Figure 2E). Finally, we used GC-MS analyses to examine whether Pantoea sp. YR343 could produce IAA, which is synthesized from the amino acid tryptophan (Patten and Glick, 1996). The tryptophan-dependent production of IAA was confirmed by GC-MS analyses and measured at approximately 0.5 μg/ml.

Bottom Line: The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host.Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots.YR343.

View Article: PubMed Central - PubMed

Affiliation: Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA.

ABSTRACT
The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host. A better understanding of the microbial mechanisms that promote plant health and stress tolerance will enable strategies for improving the productivity of economically important plants. Pantoea sp. YR343 is a motile, rod-shaped bacterium isolated from the roots of Populus deltoides that possesses the ability to solubilize phosphate and produce the phytohormone indole-3-acetic acid (IAA). Pantoea sp. YR343 readily colonizes plant roots and does not appear to be pathogenic when applied to the leaves or roots of selected plant hosts. To better understand the molecular mechanisms involved in plant association and rhizosphere survival by Pantoea sp. YR343, we constructed a mutant in which the crtB gene encoding phytoene synthase was deleted. Phytoene synthase is responsible for converting geranylgeranyl pyrophosphate to phytoene, an important precursor to the production of carotenoids. As predicted, the ΔcrtB mutant is defective in carotenoid production, and shows increased sensitivity to oxidative stress. Moreover, we find that the ΔcrtB mutant is impaired in biofilm formation and production of IAA. Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots. Taken together, these data suggest that carotenoids are important for plant association and/or rhizosphere survival in Pantoea sp. YR343.

No MeSH data available.


Related in: MedlinePlus