Figure 1. The structural formula of camalexin

Materials and Reagents

1. Arabidopsis leaves
   
2. Liquid nitrogen
   
3. Dichloromethane (DCM) (Sigma-Aldrich, catalog number: 270997 )
   
4. Methanol (LC/MS grade) (Carlo Erba Reagents, catalog number: 414831 )
   
5. Formic acid (gradient grade) (Sigma-Aldrich, catalog number: F0507 )
   
6. Water with 0.1% formic acid (LC/MS grade) (Sigma-Aldrich, catalog number: 34673 )
   
7. Camalexin standard (Sigma-Aldrich, catalog number: SML1016 )
   
8. Extraction buffer (see Recipes)
   

Equipment

1. Mortar and pestle
   
2. Spatula
   
3. Glass Pasteur pipettes
   
4. Tube adapters
   
5. Screw cap round bottom borosilicate glass culture tubes (16 x 125 mm) (Pyrex) (Sigma-Aldrich, catalog number: Z653594-40EA )
   
6. Disposable borosilicate glass culture tubes (Pyrex)
   
7. Spin-X centrifuge tube filters with nylon membranes (Sigma-Aldrich, catalog number: CLS8170-200EA )
   
8. Glass vials with cap (capacity: 100 µl)
   
9. Vortex mixer
   
10. Rocking shaker
    
11. Nitrogen evaporator (e.g. sample concentrator with dry block DB-3D) (Techne) (Figure 1)
    
12. Balance
    
13. Variable speed refrigerated centrifuge with rotor having number of rotor cavities x nominal largest load (capacity: 8 x 50 ml) (e.g. Beckman Coulter)
    
14. HPLC (e.g. Thermo Fisher Scientific, model: UltiMate 3000 HPLC )
    
15. High performance reversed-phase columns C18 for the separation of small molecules (e.g. Acclaim120 C18 Reverse-phase column-3 μm, 200 Å, 2.1 x 150 mm) (Thermo Fisher Scientific, catalog number: 059130 )
    
16. ESI-Mass Spectrometer (e.g. Orbitrap XL Discovery, Thermo Fisher Scientific)
    

Software

1. Analysis software (e.g. Thermo Xcalibur software 2.10, Thermo Fisher Scientific)

Procedure