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Molecular and chemical dialogues in bacteria-protozoa interactions.

Song C, Mazzola M, Cheng X, Oetjen J, Alexandrov T, Dorrestein P, Watrous J, van der Voort M, Raaijmakers JM - Sci Rep (2015)

Bottom Line: Lipopeptide (LP) biosynthesis was induced in Pseudomonas upon protozoan grazing and LP accumulation transitioned from homogeneous distributions across bacterial colonies to site-specific accumulation at the bacteria-protist interface.Also putrescine biosynthesis was upregulated in P. fluorescens upon predation.This multifaceted study provides new insights in common and strain-specific responses in bacteria-protozoa interactions, including responses that contribute to bacterial survival in highly competitive soil and rhizosphere environments.

View Article: PubMed Central - PubMed

Affiliation: 1] Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, the Netherlands [2] Microbial Ecology Department, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, the Netherlands.

ABSTRACT
Protozoan predation of bacteria can significantly affect soil microbial community composition and ecosystem functioning. Bacteria possess diverse defense strategies to resist or evade protozoan predation. For soil-dwelling Pseudomonas species, several secondary metabolites were proposed to provide protection against different protozoan genera. By combining whole-genome transcriptome analyses with (live) imaging mass spectrometry (IMS), we observed multiple changes in the molecular and chemical dialogues between Pseudomonas fluorescens and the protist Naegleria americana. Lipopeptide (LP) biosynthesis was induced in Pseudomonas upon protozoan grazing and LP accumulation transitioned from homogeneous distributions across bacterial colonies to site-specific accumulation at the bacteria-protist interface. Also putrescine biosynthesis was upregulated in P. fluorescens upon predation. We demonstrated that putrescine induces protozoan trophozoite encystment and adversely affects cyst viability. This multifaceted study provides new insights in common and strain-specific responses in bacteria-protozoa interactions, including responses that contribute to bacterial survival in highly competitive soil and rhizosphere environments.

No MeSH data available.


Related in: MedlinePlus

(A) MALDI imaging mass spectrometry (IMS) shows production of 249–688 m/z ions in the MS/MS network of the P. fluorescens SS101-N. americana interaction. a.u. = arbitrary units. (B) MALDI imaging mass spectrometry (IMS) shows production of 752–796 m/z ions cluster in the MS/MS network of the P. fluorescens SS101-N. americana interaction. The green box-line indicates N. americana alone; the red box-line indicates P. fluorescens SS101-N. americana interaction; the yellow box-line indicates P. fluorescens SS101 alone.
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f5: (A) MALDI imaging mass spectrometry (IMS) shows production of 249–688 m/z ions in the MS/MS network of the P. fluorescens SS101-N. americana interaction. a.u. = arbitrary units. (B) MALDI imaging mass spectrometry (IMS) shows production of 752–796 m/z ions cluster in the MS/MS network of the P. fluorescens SS101-N. americana interaction. The green box-line indicates N. americana alone; the red box-line indicates P. fluorescens SS101-N. americana interaction; the yellow box-line indicates P. fluorescens SS101 alone.

Mentions: Apart from the massetolides, other ions with predicted masses ranging from 249–688 m/z were co-localized with the green cluster in the segmentation map (Fig. 3B, Table S2). These ions were detected in the interaction, in bacteria or in the protozoa alone (Fig. 5A; Table S2). One of the ions with a mass of 477 m/z clustered with seven other ions in the MS/MS network (Fig. 3C; Table S5). Ion 325 m/z, whose intensity is higher in the bacteria-protozoa interaction than in the bacteria alone (Fig. 5A), will need to be investigated in more detail by tandem MS analyses to resolve its identity. Furthermore, next to the representative ions shown in Fig. 5B, a number of other ions were present (Table S2) including three ions with a mass of 740 m/z, 741 m/z and 767 m/z belonging to the green class, and sixteen ions with masses ranging from 703 m/z to 790 m/z (Table S2) belonging to the dark red class from the segmentation map. The ion with a mass of 766 m/z clustered in the network with nine other ions with masses ranging from 752 m/z to 796 m/z (Fig. 3C; Table S6). Preliminary MS/MS analyses showed that four of these ions exhibit a similar fragmentation pattern with a 123.9 Da loss (not shown). Resolving the identity of this metabolite class will be subject of future experiments.


Molecular and chemical dialogues in bacteria-protozoa interactions.

Song C, Mazzola M, Cheng X, Oetjen J, Alexandrov T, Dorrestein P, Watrous J, van der Voort M, Raaijmakers JM - Sci Rep (2015)

(A) MALDI imaging mass spectrometry (IMS) shows production of 249–688 m/z ions in the MS/MS network of the P. fluorescens SS101-N. americana interaction. a.u. = arbitrary units. (B) MALDI imaging mass spectrometry (IMS) shows production of 752–796 m/z ions cluster in the MS/MS network of the P. fluorescens SS101-N. americana interaction. The green box-line indicates N. americana alone; the red box-line indicates P. fluorescens SS101-N. americana interaction; the yellow box-line indicates P. fluorescens SS101 alone.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542665&req=5

f5: (A) MALDI imaging mass spectrometry (IMS) shows production of 249–688 m/z ions in the MS/MS network of the P. fluorescens SS101-N. americana interaction. a.u. = arbitrary units. (B) MALDI imaging mass spectrometry (IMS) shows production of 752–796 m/z ions cluster in the MS/MS network of the P. fluorescens SS101-N. americana interaction. The green box-line indicates N. americana alone; the red box-line indicates P. fluorescens SS101-N. americana interaction; the yellow box-line indicates P. fluorescens SS101 alone.
Mentions: Apart from the massetolides, other ions with predicted masses ranging from 249–688 m/z were co-localized with the green cluster in the segmentation map (Fig. 3B, Table S2). These ions were detected in the interaction, in bacteria or in the protozoa alone (Fig. 5A; Table S2). One of the ions with a mass of 477 m/z clustered with seven other ions in the MS/MS network (Fig. 3C; Table S5). Ion 325 m/z, whose intensity is higher in the bacteria-protozoa interaction than in the bacteria alone (Fig. 5A), will need to be investigated in more detail by tandem MS analyses to resolve its identity. Furthermore, next to the representative ions shown in Fig. 5B, a number of other ions were present (Table S2) including three ions with a mass of 740 m/z, 741 m/z and 767 m/z belonging to the green class, and sixteen ions with masses ranging from 703 m/z to 790 m/z (Table S2) belonging to the dark red class from the segmentation map. The ion with a mass of 766 m/z clustered in the network with nine other ions with masses ranging from 752 m/z to 796 m/z (Fig. 3C; Table S6). Preliminary MS/MS analyses showed that four of these ions exhibit a similar fragmentation pattern with a 123.9 Da loss (not shown). Resolving the identity of this metabolite class will be subject of future experiments.

Bottom Line: Lipopeptide (LP) biosynthesis was induced in Pseudomonas upon protozoan grazing and LP accumulation transitioned from homogeneous distributions across bacterial colonies to site-specific accumulation at the bacteria-protist interface.Also putrescine biosynthesis was upregulated in P. fluorescens upon predation.This multifaceted study provides new insights in common and strain-specific responses in bacteria-protozoa interactions, including responses that contribute to bacterial survival in highly competitive soil and rhizosphere environments.

View Article: PubMed Central - PubMed

Affiliation: 1] Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, the Netherlands [2] Microbial Ecology Department, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, the Netherlands.

ABSTRACT
Protozoan predation of bacteria can significantly affect soil microbial community composition and ecosystem functioning. Bacteria possess diverse defense strategies to resist or evade protozoan predation. For soil-dwelling Pseudomonas species, several secondary metabolites were proposed to provide protection against different protozoan genera. By combining whole-genome transcriptome analyses with (live) imaging mass spectrometry (IMS), we observed multiple changes in the molecular and chemical dialogues between Pseudomonas fluorescens and the protist Naegleria americana. Lipopeptide (LP) biosynthesis was induced in Pseudomonas upon protozoan grazing and LP accumulation transitioned from homogeneous distributions across bacterial colonies to site-specific accumulation at the bacteria-protist interface. Also putrescine biosynthesis was upregulated in P. fluorescens upon predation. We demonstrated that putrescine induces protozoan trophozoite encystment and adversely affects cyst viability. This multifaceted study provides new insights in common and strain-specific responses in bacteria-protozoa interactions, including responses that contribute to bacterial survival in highly competitive soil and rhizosphere environments.

No MeSH data available.


Related in: MedlinePlus