HS-SPME-GC/MS data for the whole plant volatilome in Arabidopsis

Arabidopsis (Col-0) plants was grown under a 16 h photoperiod, at ~120 µEm-2s-1 light intensity, on Debco Seed Raising Mix (Scotts Australia, Australia), supplemented with 3 g/L Osmocote controlled-release fertilizer (Scotts Australia, Australia). Plant samples were staged and freshly harvested as previously described (Rivers et al. 2019), promptly sealed in headspace amber glass vials (20 mL) using magnetic crimp caps with silicone septa and analysed immediately. For most tissues (n = 3-5), 500 mg were used per biological replicate and 40 mg for bud samples.
Volatile standard preparation was carried out with high purity grade (>90%) α-cyclocitral; α-ionone; β-cyclocitral; β-cyclocitrol; β-ionol; β-ionone; citral; farnesylacetone; geranylacetone; 6-methyl-5-hepten-2-one; pseudoionone; 1 mg/ml n-alkanes mix (C9-C36, Cat. No. 49451-U) (Sigma-Aldrich, Sydney, Australia); (S)-Dihydroactinidiolide (>97%) (4C Pharma, Ontario, Canada); and 13,13,13-D3-β-ionone (>99%) (Buchem BV, Netherlands) and resuspended in GC/MS-grade ethyl acetate (Sigma-Aldrich, Sydney, Australia) or GC/MS-grade dichloromethane (Thermo Fisher (Melbourne, Australia). Stock solutions containing each apocarotenoid standard at 1 mg/mL were prepared in ethyl acetate and stored in amber glass vials at −20°C, and diluted as required for calibration and quality control standards. n-alkane mix was diluted using dichloromethane.
Plant tissue samples and quality assurance and quality control standards were randomised within statistical ‘blocks’ to account for any systemic fluctuations during SPME-GC/MS sequence analysis as previously described (Rivers et al., 2019). Quality control laboratory blanks (empty HS vials exposed to the laboratory environment during sample and standard preparation prior to capping) were also interspersed to check for carry-over contamination between samples, fibre bleed, and to account for other laboratory VOCs.
HS-SPME-GC/MS volatile compound separation was carried out as previous described (Rivers et al., 2019) on a single quadrupole GC/MSD instrument (Agilent Technologies, Palo Alto, CA, USA) consisting of a 7890A series gas chromatograph with a split/splitless injector and a 5975C inert XL MSD mass selective detector (Triple-Axis Detector). The system was retrofitted with a MPS 2 Gerstel Multipurpose sampler with normal liquid injection and HS-SPME capability (Gerstel GmbH & Co. KG, Germany). Splitless injection was used with a 1.0 mm straight no-wool liner and the inlet temperature set at 250oC. VOC chromatographic separation was achieved on a non-polar Agilent J&W VF-5 ms column (30 m × 0.25 mm × 0.25 μm), equipped with a 10 m EZ-Guard column. The oven temperature programme was as follows: 40°C for 2 min, ramping to 150°C at 5°C/min and held for 2 min, then to 320°C at a ramp rate of 15°C/min and held for 1 min. The helium (ultra-high purity, BOC Australia) carrier gas flow rate was 1 mL/min. Aux transfer line temperature was 320°C, ion source 250°C and quadrupole 150°C. Electron impact ionisation energy (EI) was 70 eV, with full MS scan acquisition from m/z 40 to 500, and four minutes solvent delay. The GC/MS run time was 38 min.