Fig. S1a. The development cycle of Ulva mutabilis (wt and mutant “slender”).

Fig. S1b. Phenotype of nonaxenic Ulva mutabilis grown under standard culture conditions in presence of their complete accompanying microbial flora. wt G-: wt gametophyte (mt−); sl G+: mutant slender gametophyte (mt +); w: age in weeks.

jpy1231-sup-0002-FigS2.pdfapplication/PDF99KFig. S2. Monitoring of axenicity by “direct PCR” (cf. material and methods) and agarose gel-electrophoresis: amplification of a part of the 16S rDNA (520 bp) gene from intact bacteria in algal growth media. Lane 1: Gene Ruler Express DNA ladder (Fermentas, St. Leon-Rot, Germany); lane 2: nonaxenic culture of Ulva mutabilis; lane 3: Ulva cultured with Roseobacter sp.; lane 4: axenic culture of U. mutabilis.
jpy1231-sup-0003-FigS3.pdfapplication/PDF158KFig. S3. Phenotypes of the bacterial colonies and TEM pictures of the bacterial cells. Bacteria producing a morphogenetic activity were grown on SWC plates (left) and samples were inspected by TEM (right, bar = 1 μm). The bacteria were fixated in glutaraldehyde (2% v/v) for 30 min and metalized with 1 nm Pt/C at an angel of 15°. (a) Halomonas MS1 (b) Roseobacter MS2 (bacteria without flagellae from a stationary phase culture) (c) Sulfitobacter MS3 (d) Cytophaga MS6.
jpy1231-sup-0004-FigS4.pdfapplication/PDF150KFig. S4. Spatial separation of bacteria and the mutant “slender” of Ulva mutabilis. Bacteria were cultured separated from the axenic algae by a 0.02 μm membrane filter. Incomplete (a) and complete (b) morphogenesis induced by diffusible bacterial compounds of Roseobacter sp. (MS2) and Cytophaga sp. (MS6) after 3 weeks of cultivation. Petri dishes on the left side in (a) and (b) show the control experiments with direct contact of the bacteria and algae. This material is available as part of the online article.

Please note: Wiley Blackwell is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.