Streptomyces exploration is triggered by fungal interactions and volatile signals
- McMaster University, Canada
- University of Toronto, Canada
- Dartmouth College, United States
Figures
Figure 1 with 3 supplements
Physical association with yeast triggers Streptomyces exploratory behaviour.
(A) Developmental life cycle of Streptomyces. Germ tubes emerge from a single spore, and grow by apical tip extension and hyphal branching, forming a dense network of branching vegetative hyphae. In …
Figure 1—figure supplement 1
Explorer cells are hydrophilic.
S. venezuelae growing on top of S. cerevisiae cells raise hydrophobic aerial hyphae and spores. These structures effectively repel aqueous droplets (bromophenol blue dye dissolved in water). In …
Figure 1—figure supplement 2
Phylogeny of exploratory streptomycetes.
The phylogeny was created using aligned rpoB sequences from wild Streptomyces isolates (WAC strains) that exhibited exploratory growth. For comparison, we included the non-spreading S. coelicolor, …
Figure 1—figure supplement 3
S. venezuelae grown beside diverse yeast strains.
S. venezuelae was grown beside the indicated yeast strains on YPD agar medium for 14 days. Z. florentinus, S. castellii, S. cerevisiae, D. honsenii, and P. fermentas are soil isolates, while C. …
Figure 2 with 2 supplements
Yeast stimulates S. venezuelae exploratory growth by consuming glucose and inhibits it by acidifying the medium.
(A) S. cerevisiae mutants that fail to stimulate S. venezuelae exploratory growth. Left: functional grouping of the exploration-deficient S. cerevisiae mutations. Asterisks indicate genes also …
Figure 2—figure supplement 1
C. albicans gene mutations that affect S. venezuelae exploratory growth.
S. venezuelae (S. ven.) was inoculated alone or beside wild type (WT), ΔLPD1, or ΔKGD2 C. albicans strains on YPD agar for 10 days. C. albicans mutant strains were from the GRACE collection of …
Figure 2—figure supplement 2
S. venezuelae grown alone on glucose-deficient medium exhibits similar exploratory growth to S. venezuelae growing next to yeast on glucose medium.
S. venezuelae was grown either alone or beside S. cerevisiae on G+ (glucose-containing) agar medium, and alone on G- (no glucose). Two replicates were spotted per plate, and plates were incubated …
Figure 3 with 3 supplements
The alkaline stress response is associated with S. venezuelae exploratory behaviour.
(A) The surface area and medium pH associated with S. venezuelae explorer cells beside S. cerevisiae on YPD agar were measured and plotted every day for 14 days. (B) Schematic of the method used to …
Figure 3—figure supplement 1
S. venezuelae grown alone raises the pH of glucose-deficient medium.
S. venezuelae was grown alone on G- (no glucose) or G+ (glucose-containing) agar medium containing the pH indicator bromothymol blue. Two replicates were inoculated on each plate, and these were …
Figure 3—figure supplement 2
High pH alone does not stimulate S. venezuelae exploration.
S. venezuelae was grown alone on YPD agar medium buffered to pH 9.0 using 50, 100 or 200 mM borate. Two replicates were inoculated on each plate, and these were grown for 14 days.
Figure 3—figure supplement 3
Complementation of explorer mutant phenotypes.
Top row: EMS (ethyl methanesulfonate) mutagenesis-derived S. venezuelae explorer mutants containing point mutations in the cydABCD operon, grown beside S. cerevisiae. Bottom row: Explorer mutants …
Figure 4 with 3 supplements
Volatile organic compounds released by S. venezuelae raise the medium pH and induce exploratory growth in physically separated Streptomyces.
(A) Effect of S. venezuelae explorer cells on pH of physically separated medium. Each compartment is separated by a polystyrene barrier. S. venezuelae and S. cerevisiae were grown in the left …
Figure 4—figure supplement 1
The S. venezuelae cydCD mutant strain can explore in response to volatile signals produced by neighbouring explorer cells.
Left: Wild type (WT) S. venezuelae was grown beside S. cerevisiae in the left compartment, and the S. venezuelae cydCD mutant strain was grown alone in the right compartment. Middle: Wild type S. …
Figure 4—figure supplement 2
Wild explorer Streptomyces species promote exploration in S. venezuelae using volatile signals.
Using our two-quadrant assay, 13 independent wild Streptomyces isolates (WAC strains) were inoculated on G- agar, adjacent to S. venezuelae inoculated on G+ agar medium (where no exploration was …
Figure 4—figure supplement 3
The VOC produced by S. venezuelae explorer cells can be produced by liquid-grown (G-) S. venezuelae and WAC0566 cultures.
All strains were grown in 48-well plates, with (l) indicating liquid cultures (top rows), and (s) indicating solid YPD agar (bottom rows). Liquid cultures were either G+ (glucose-containing) or G- …
Figure 5
S. venezuelae VOCs inhibit the growth of other bacteria.
(A) S. venezuelae was grown beside S. cerevisiae (left) or alone (right) on YPD agar in a small dish placed within a larger dish containing YPD medium. After 10 days, an indicator strain (B. subtilis…
Figure 6
New model for Streptomyces development.
When S. venezuelae is grown alone on glucose-rich medium S. venezuelae exploratory growth is repressed (left). When S. venezuelae is grown beside S. cerevisiae or other yeast on glucose-rich medium …
Author response image 1
Videos
Video 1
Leading edge of S. venezuelae explorer cells over a 17 hr time course.
https://doi.org/10.7554/eLife.21738.007Additional files
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Supplementary file 1
Supplementary tables.
(a) VOCs identified using GC×GC-TOFMS. (b) Effects of media composition on S. venezuelae exploration when grown in the absence of yeast. (c) Oligonucleotides used in this study.
- https://doi.org/10.7554/eLife.21738.021
