Materials and Reagents

1. 1 ml syringes (Henke Sass-Wolf, catalog number: 5100.200V0 )
   
2. Needles (16 G, 40 mm) (Premier Healthcare & Hygiene, BD microlance, catalog number: 300637 )
   
3. 50 ml Falcon tubes (Sigma-Aldrich, catalog number: T2318 )
   
4. Glass test tubes (Carl Roth GmbH + Co, catalog number: HA79.1 )
   
5. Soil (Frühstorfer Pikiererde T type soil) and Pots
   
6. Ustilago maydis strains
   Note: The U. maydis wild-type or any transgenic strains are maintained as glycerol stock in -80 °C for long term storage. Every strain can be retrieved on a PDA plate.
   
7. Maize seeds (e.g., variety Early Golden Bantam or Gaspe Flint)
   Note: The maize variety Early Golden Bantam is a standard maize line that requires around 4 weeks for the floral switch and development of the male inflorescence. The maize variety Gaspe Flint is a mutant maize that completes its life cycle in 35-38 days and hence has an early floral switch with the development of male inflorescence around 15 days after sowing. Hence this variety is suitable for floral infections with U. maydis.
   
8. Yeast extract (BD, Difco, catalog number: 210934 )
   
9. Peptone (BD, Difco, catalog number: 211830 )
   
10. Sucrose (Carl Roth GmbH + Co, catalog number: 9097.2 )
    
11. Double distilled water
    
12. 2.4% Potato Dextrose Broth (BD, Difco, catalog number: 254920 )
    
13. 2% agar (BD, Difco, catalog number: 214010 )
    
14. YEPS_L medium (modified from Tsukada et al., 1988) (see Recipes)
    
15. Potato Dextrose Agar (PDA) plates (see Recipes)
    

Equipment

1. Greenhouse
   
2. Erlenmeyer flasks (250 ml)
   
3. Disposable cuvettes (Carl Roth GmbH + Co, catalog number: Y195.1 )
   
4. Incubator [e.g., Certomat BS-1 (B. Braun Biotech International)]
   
5. Centrifuge (Thermo Fisher Scientific)
   
6. Spectrophotometer [e.g. Ultrospec 3000 proUV/Visible (GE Healthcare)]
   
7. Knife
   

Procedure