Limits...
Identification of Genetic Modules Mediating the Jekyll and Hyde Interaction of Dinoroseobacter shibae with the Dinoflagellate Prorocentrum minimum.

Wang H, Tomasch J, Michael V, Bhuju S, Jarek M, Petersen J, Wagner-Döbler I - Front Microbiol (2015)

Bottom Line: Here, we identified key genetic components of this interaction.By contrast, pathogenicity was entirely dependent on one of the extrachromosomal elements of D. shibae, the 191 kb plasmid.The data show that flagella and the CtrA phosphorelay are required for establishing mutualism and prove a cell density dependent killing effect of D. shibae on P. minimum which is mediated by an unknown factor encoded on the 191 kb plasmid.

View Article: PubMed Central - PubMed

Affiliation: Helmholtz-Centre for Infection Research, Microbial Communication Braunschweig, Germany.

ABSTRACT
The co-cultivation of the alphaproteobacterium Dinoroseobacter shibae with the dinoflagellate Prorocentrum minimum is characterized by a mutualistic phase followed by a pathogenic phase in which the bacterium kills aging algae. Thus it resembles the "Jekyll-and-Hyde" interaction that has been proposed for other algae and Roseobacter. Here, we identified key genetic components of this interaction. Analysis of the transcriptome of D. shibae in co-culture with P. minimum revealed growth phase dependent changes in the expression of quorum sensing, the CtrA phosphorelay, and flagella biosynthesis genes. Deletion of the histidine kinase gene cckA which is part of the CtrA phosphorelay or the flagella genes fliC or flgK resulted in complete lack of growth stimulation of P. minimum in co-culture with the D. shibae mutants. By contrast, pathogenicity was entirely dependent on one of the extrachromosomal elements of D. shibae, the 191 kb plasmid. The data show that flagella and the CtrA phosphorelay are required for establishing mutualism and prove a cell density dependent killing effect of D. shibae on P. minimum which is mediated by an unknown factor encoded on the 191 kb plasmid.

No MeSH data available.


Related in: MedlinePlus

Growth of P. minimum and different D. shibae mutants in co-culture.P. minimum cell numbers are shown on the left, D. shibae cell numbers are shown on the right. The P. minimum positive and negative controls as well as the growth of the co-culture with wild-type D. shibae are shown in every panel for comparison. (A) Co-culture with the quorum sensing -mutant D. shibae ΔluxI1, (B) with the phosphorelay knock-out mutants D. shibae ΔcckA and ΔctrA-191, the latter additionally lacking the 191 kb plasmid, and a Δ191 kb cured mutant with intact ctrA gene, (C) with D. shibae ΔfliC and Δflik, lacking functional flagella. Data represent mean and standard deviation of three biological replicates.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4643747&req=5

Figure 3: Growth of P. minimum and different D. shibae mutants in co-culture.P. minimum cell numbers are shown on the left, D. shibae cell numbers are shown on the right. The P. minimum positive and negative controls as well as the growth of the co-culture with wild-type D. shibae are shown in every panel for comparison. (A) Co-culture with the quorum sensing -mutant D. shibae ΔluxI1, (B) with the phosphorelay knock-out mutants D. shibae ΔcckA and ΔctrA-191, the latter additionally lacking the 191 kb plasmid, and a Δ191 kb cured mutant with intact ctrA gene, (C) with D. shibae ΔfliC and Δflik, lacking functional flagella. Data represent mean and standard deviation of three biological replicates.

Mentions: When the QS mutant ΔluxI1 was cultivated together with P. minimum (Figure 3A) it grew faster than the wild-type, in accordance with its smaller cell size and higher growth rate in pure culture described previously (Patzelt et al., 2013). In contrast to the growth of the wild-type, cell numbers of the QS mutant doubled within the first 3 days, even when cultivated alone in the medium without C-source. In co-culture cell numbers doubled initially as well, but – like in the wild-type – substantial growth started only at day 12. From then on, the mutant grew marginally faster than the wild-type and it reached slightly lower final cell densities. Interestingly, the decrease in the cell numbers of P. minimum started 3 days earlier in co-culture with the QS mutant than in co-culture with the wild-type. The earlier start of the pathogenic phase might be a result of the faster growth rate of the QS mutant and indicates a dosage effect, i.e., a larger number of cells has a stronger killing effect, in accordance with previous observations (Wagner-Döbler et al., 2010).


Identification of Genetic Modules Mediating the Jekyll and Hyde Interaction of Dinoroseobacter shibae with the Dinoflagellate Prorocentrum minimum.

Wang H, Tomasch J, Michael V, Bhuju S, Jarek M, Petersen J, Wagner-Döbler I - Front Microbiol (2015)

Growth of P. minimum and different D. shibae mutants in co-culture.P. minimum cell numbers are shown on the left, D. shibae cell numbers are shown on the right. The P. minimum positive and negative controls as well as the growth of the co-culture with wild-type D. shibae are shown in every panel for comparison. (A) Co-culture with the quorum sensing -mutant D. shibae ΔluxI1, (B) with the phosphorelay knock-out mutants D. shibae ΔcckA and ΔctrA-191, the latter additionally lacking the 191 kb plasmid, and a Δ191 kb cured mutant with intact ctrA gene, (C) with D. shibae ΔfliC and Δflik, lacking functional flagella. Data represent mean and standard deviation of three biological replicates.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643747&req=5

Figure 3: Growth of P. minimum and different D. shibae mutants in co-culture.P. minimum cell numbers are shown on the left, D. shibae cell numbers are shown on the right. The P. minimum positive and negative controls as well as the growth of the co-culture with wild-type D. shibae are shown in every panel for comparison. (A) Co-culture with the quorum sensing -mutant D. shibae ΔluxI1, (B) with the phosphorelay knock-out mutants D. shibae ΔcckA and ΔctrA-191, the latter additionally lacking the 191 kb plasmid, and a Δ191 kb cured mutant with intact ctrA gene, (C) with D. shibae ΔfliC and Δflik, lacking functional flagella. Data represent mean and standard deviation of three biological replicates.
Mentions: When the QS mutant ΔluxI1 was cultivated together with P. minimum (Figure 3A) it grew faster than the wild-type, in accordance with its smaller cell size and higher growth rate in pure culture described previously (Patzelt et al., 2013). In contrast to the growth of the wild-type, cell numbers of the QS mutant doubled within the first 3 days, even when cultivated alone in the medium without C-source. In co-culture cell numbers doubled initially as well, but – like in the wild-type – substantial growth started only at day 12. From then on, the mutant grew marginally faster than the wild-type and it reached slightly lower final cell densities. Interestingly, the decrease in the cell numbers of P. minimum started 3 days earlier in co-culture with the QS mutant than in co-culture with the wild-type. The earlier start of the pathogenic phase might be a result of the faster growth rate of the QS mutant and indicates a dosage effect, i.e., a larger number of cells has a stronger killing effect, in accordance with previous observations (Wagner-Döbler et al., 2010).

Bottom Line: Here, we identified key genetic components of this interaction.By contrast, pathogenicity was entirely dependent on one of the extrachromosomal elements of D. shibae, the 191 kb plasmid.The data show that flagella and the CtrA phosphorelay are required for establishing mutualism and prove a cell density dependent killing effect of D. shibae on P. minimum which is mediated by an unknown factor encoded on the 191 kb plasmid.

View Article: PubMed Central - PubMed

Affiliation: Helmholtz-Centre for Infection Research, Microbial Communication Braunschweig, Germany.

ABSTRACT
The co-cultivation of the alphaproteobacterium Dinoroseobacter shibae with the dinoflagellate Prorocentrum minimum is characterized by a mutualistic phase followed by a pathogenic phase in which the bacterium kills aging algae. Thus it resembles the "Jekyll-and-Hyde" interaction that has been proposed for other algae and Roseobacter. Here, we identified key genetic components of this interaction. Analysis of the transcriptome of D. shibae in co-culture with P. minimum revealed growth phase dependent changes in the expression of quorum sensing, the CtrA phosphorelay, and flagella biosynthesis genes. Deletion of the histidine kinase gene cckA which is part of the CtrA phosphorelay or the flagella genes fliC or flgK resulted in complete lack of growth stimulation of P. minimum in co-culture with the D. shibae mutants. By contrast, pathogenicity was entirely dependent on one of the extrachromosomal elements of D. shibae, the 191 kb plasmid. The data show that flagella and the CtrA phosphorelay are required for establishing mutualism and prove a cell density dependent killing effect of D. shibae on P. minimum which is mediated by an unknown factor encoded on the 191 kb plasmid.

No MeSH data available.


Related in: MedlinePlus