Fig. 5.

The log₂-fold changes in the VOCs of 50 annotated peaks in the VOC profiles of sulfur-containing peaks (a), peaks consisting of CHO (b), and peaks consisting of CH (c). The log₂-fold changes (log2FC) in the normalized response of peaks of each cultivar (A. chinense or A. tuberosum) against that of the control cultivar class01 (A. fistulosum) are shown in the Additional file 3. We analyzed three biological replicates of each Allium plant except the white spring onion (class05, n = 2) cultivar. Asterisks on the top of the bars present that the level of VOCs in A. chinense and/or A. tuberosum was significantly changed using the LIMMA package (see the “Methods” section) when compared to the control cultivar (class01 in Table 1). The significance level was set at FDR <0.05 (asterisk *). Sulfur-containing peaks were: ID020 1-propene, 3,3’-thiobis, ID021 methanesulfonic acid, methyl ester, ID024 thiophene, 2,5-dimethyl, ID026 3,4-dimethylthiophene, ID028 thiophene, 2-ethenyl, ID032 thiophene, 2,4-dimethyl, ID054 dimethyl trisulfide, ID065 3-thiophenecarboxaldehyde, ID086 S-methyl methanethiosulphonate, ID091 diallyl disulphide, ID092 5-methyl-2-thiophenecarboxaldehyde, ID099 1,2,4-trithiolane, ID101 dipropyl disulfide, ID119 prop-1-enyl dithiopropanonate, ID124 thiophene, 2-propyl, ID134 3-vinyl-1,2-dithiacyclohex-5-ene, ID154 2,5-thiophenedicarboxaldehyde, ID164 trisulfide, di-2-propenyl, ID172 trisulfide, dipropyl, ID176 1,2,4-trithiolane, 3,5-diethyl, ID200 thieno[2,3-b]thiophene, 2-methyl, ID358 cyclic octaatomic sulfur, ID377 disulfide, methyl 1-propenyl, Peaks consisting of CHO: ID002 hexanal, ID011 2-butenal, 2-ethyl, ID012 2-pentenal, 2-methyl, ID050 heptenal, (2E), ID063 2-furanone, 2,5-dihydro-3,5-dimethyl; ID083 octen-1-al, (2E); ID088 2-octen-1-ol, (E); ID141 nonanoic acid; ID143 decenal, (2E); ID167 decadienal, (2E,4E); ID179 2-dodecenal, (E); ID201 3(2H)-furanone, 2-hexyl-5-methyl; ID218 2-tridecanone; ID259 3(2H)-furanone, 5-methyl-2-octyl; ID328 hexadecanoic acid methyl ester, n; ID334 1,2-benzenedicarboxylic acid, butyl octyl ester; ID354 9,12-octadecadienoic acid, methyl ester, (E,E); ID365 [1,1′,3′,1′-terphenyl]-2′-ol; ID371 2,5-cyclohexadiene-1,4-dione, 2,5-diphenyl; ID383 benzaldehyde; Peaks consisting of CH: ID139 benzene, 1,3-bis(1,1-dimethylethyl); ID266 8-heptadecene; ID273 heptadecane, n; ID279 1,1′-biphenyl, 2,2′,5,5′-tetramethyl; ID317 5-octadecene, (E); ID322 nonadecane; ID368 tricosane