Table 1.

Annotation of discriminatory metabolites belonging to various chemical classes and related to Burkholderia andropogonis-induced metabolic reprogramming in Sorghum bicolor plants. Following UHPLC-MS analysis, the selected features from both ESI (+/−) modes, were extracted from OPLS-DA S-plots and annotated at MSI-level 2. The reported fold changes for cultivars NS 5511 and NS 5655 were obtained from an OPLS-DA model of control vs. all treated/infected samples (1–9 d.p.i.).

Metabolites	m/z	RT (min)	Adduct	Ion Mode	Molecular Formula	NS 5511		NS 5655		Metabolite Class
						p-Value	Fold Change	p-Value	Fold Change
l-Phenylalanine	180.092	2.59	[M−H_NH3]−	neg	C9H11NO2	0.159	0.9	0.002	0.9	Amino acid
l-Tyrosine	182.081	1.13	[M+H]+	pos	C9H11NO3	1.77 × 10−31	0.5	1.94 × 10−31	0.4	Amino acid
l-Tryptophan	205.097	2.69	[M+H]+	pos	C11H12N2O2	1.87 × 10−27	0.6	2.67 × 10−15	0.5	Amino acid
Benzoic acid	121.028	4.46	[M−H]−	neg	C7H6O2	1.76 × 10-20	0.6	0.603	0.7	Benzoates
Dhurrin	334.090	2.6	[M+H_Na]+	pos	C14H17NO7	2.49 × 10−29	0.4	2.51 × 10−27	0.4	Cyanogen
Apigenin	269.007	7.05	[M−H]−	neg	C15H10O5	0.838	1.0	0.000	1.5	Flavonoid
Protocatechuic acid hexoside	315.069	5.41	[M−H]−	neg	C13H16O9	5.24 × 10−7	1.5	1.67 × 10−11	2.1	Flavonoid
Tricin	329.066	8.92	[M−H]−	neg	C17H14O7	6.62 × 10−7	0.7	0.091	0.8	Flavonoid
Sophoraflavanone B	341.137	2.50	[M+H]+	pos	C20H20O5	8.06 × 10−34	0.4	4.38 × 10−27	0.4	Flavonoid
Trihydroxypentamethoxyflavone	419.095	5.69	[M−H]−	neg	C20H20O10	1.64 × 10−24	3.1	1.31 × 10−16	3.8	Flavonoid
Sophoraflavanone G	423.182	5.46	[M−H]−	neg	C25H28O6	4.59 × 10−11	0.6	1.29 × 10−5	0.7	Flavonoid
Apigenin-8-C-glucoside (vitexin)	431.099	5.55	[M−H]−	neg	C21H20O10	7.57 × 10−5	1.4	0.347	1.1	Flavonoid
Apigetrin (apigenin 7-O-glucoside)	431.098	6.33	[M−H]−	neg	C21H20O10	0.238	1.0	0.001	0.8	Flavonoid
Naringenin 7-O-beta-d-glucoside (prunin)	433.114	5.91	[M−H]−	neg	C21H22O10	1.44 × 10−16	2.3	5.76 × 10−18	4.6	Flavonoid
Luteolin 7-O-glucoside	447.091	5.71	[M−H]−	neg	C21H20O11	4.44 × 10−13	1.6	0.799	1.0	Flavonoid
Quercetin 3-O-rhamnoside (quercitrin)	447.092	4.61	[M−H]−	neg	C21H20O11	9.02 × 10−17	1.8	8.37 × 10−17	3.8	Flavonoid
Pentahydroxychalcone 4′-O-glucoside	449.108	4.57	[M−H]−	neg	C21H22O11	7.50 × 10−11	1.4	5.49 × 10−19	2.1	Flavonoid
Apigenin 8-C-xyloside-6-C-glucoside (vicenin-3)	563.139	5.09	[M−H]−	neg	C26H28O14	0.672	1.1	3.88 × 10−8	1.2	Flavonoid
Apigenin 6-C-xyloside-8-C-glucoside (vicenin-1)	563.140	4.87	[M−H]−	neg	C26H28O14	6.91 × 10−11	1.2	0.008	1.1	Flavonoid
Vitexin 2″-O-rhamnoside	577.154	5.32	[M−H]−	neg	C27H30O14	1.43 × 10−15	1.5	7.43 × 10−14	1.5	Flavonoid
Apigenin 7-O-neohesperidoside (rhoifolin)	577.156	6.06	[M−H]−	neg	C27H30O14	1.52 × 10−7	1.1	0.488	1.0	Flavonoid
Unknown flavonoid	581.149	4.33	[M−H]−	neg	C26H30O15	7.67 × 10−25	2.5	1.75 × 10−15	2.8	Flavonoid
Luteolin 7-O-neohesperidoside	593.150	5.51	[M−H]−	neg	C27H30O15	2.20 × 10−15	1.3	0.037	0.9	Flavonoid
Apigenin-6,8-di-C-glucoside (vicenin-2)	593.151	4.45	[M−H]−	neg	C27H30O15	0.637	1.0	8.60 × 10−6	1.3	Flavonoid
Quercetin-3-rhamnoside-7-rhamnoside	595.165	4.51	[M−H]−	neg	C27H32O15	2.87 × 10−9	1.4	4.17 × 10−10	1.5	Flavonoid
Quercetin rutinoside (rutin)	609.146	5.43	[M−H]−	neg	C27H30O16	1.22 × 10−19	2.1	3.98 × 10−10	2.1	Flavonoid
Hesperidin	609.181	4.80	[M−H]−	neg	C28H34O15	0.236	1.1	0.000	0.9	Flavonoid
Unknown flavonoid	611.158	3.10	[M−H]−	neg	C27H32O16	4.59 × 10−9	1.2	3.07 × 10−8	1.4	Flavonoid
Naringenin 7-O-neohesperidoside (naringin)	625.180	3.33	[M−H_HCOOH]−	neg	C27H32O14	0.000	1.1	3.10 × 10−6	0.7	Flavonoid
7-O-Methylvitexin 2″-O-beta-l-rhamnoside	637.177	6.21	[M−H_HCOOH]−	neg	C28H31O14	0.466	1.0	0.563	1.0	Flavonoid
4-Hydroxycoumarin	161.024	1.87	[M−H]−	neg	C9H6O3	3.91 × 10−12	0.6	0.017	0.8	HCA
p-Coumaric acid	163.039	3.65	[M−H]−	neg	C9H8O3	0.064	0.9	0.953	0.9	HCA
Caffeic acid	179.034	4.35	[M−H]−	neg	C9H8O4	1.68 × 10−7	0.5	0.083	0.6	HCA
Ferulic acid	193.048	4.01	[M−H]−	neg	C10H10O4	1.95 × 10−12	0.8	1.25 × 10−7	0.8	HCA
Sinapoyl alcohol	209.074	6.72	[M−H]−	neg	C11H14O4	1.48 × 10−15	2.4	1.07 × 10−16	3.1	HCA
Coniferyl acetate	221.081	7.42	[M−H]−	neg	C12H14O4	nd	nd	3.47 × 10−10	8.2	HCA
2-O-Caffeoylglyceric acid	267.048	4.38	[M−H]−	neg	C12H12O7	1.48 × 10−10	0.5	0.017	0.7	HCA
4-Coumaroylquic acid	337.051	3.29	[M−H]−	neg	C16H18O8	1.54 × 10−30	3.8	6.41 × 10−26	3.6	HCA
Caffeic acid hexose	341.083	6.17	[M−H]−	neg	C15H18O9	3.44 × 10−7	0.7	0.003	0.8	HCA
4-Caffeoylquinic acid	353.091	3.58	[M−H]−	neg	C16H18O9	4.75 × 10−23	0.3	2.60 × 10−5	0.5	HCA
1-O-Feruloyl-beta-d-glucose	355.102	4.06	[M−H]−	neg	C16H20O9	3.21 × 10−24	0.2	4.17 × 10−18	0.1	HCA
4-Coumaroylagmatine	277.027	2.63	[M−H]−	neg	C14H20N4O2	0.0464	0.9	1.09 × 10−7	0.8	HCA
3-Feruloylquinic acid	367.099	3.75	[M−H]−	neg	C17H20O9	5.98 × 10−9	1.3	0.002	1.2	HCA
Sinapoyl aldehyde	371.130	6.53	[M+H]+	pos	C17H22O9	4.70 × 10−29	0.3	3.58 × 10−22	0.4	HCA
2-O-Caffeoylglucarate	371.062	2.05	[M−H]−	neg	C15H16O11	0.167	0.3	nd	nd	HCA
1-O-Coumaroyl-beta-d-glucose	371.097	4.26	[M−H_HCOOH]−	neg	C15H18O8	0.001	1.1	0.442	1.0	HCA
Sinapoyl-(S)-malate	385.078	3.74	[M−H_HCOOH]−	neg	C15H16O9	1.56 × 10−10	0.8	0.066	0.6	HCA
1-O-Sinapoyl-beta-d-glucose	385.113	5.16	[M−H]−	neg	C17H22O10	7.38 × 10−9	0.8	0.000	0.9	HCA
Feruloylserotonin	351.072	3.65	[M−H]−	neg	C20H20N2O4	0.793	1.0	1.43 × 10−10	0.3	HCA
1,3-O-Coumaroyl-feruloylglycerol	413.121	9.03	[M−H]−	neg	C22H22O8	9.84 × 10−12	0.4	4.47 × 10−17	0.5	HCA
Sinapaldehyde glucoside	415.123	4.44	[M−H_HCOOH]−	neg	C17H22O9	7.13 × 10−16	0.7	9.48 × 10−7	0.8	HCA
1,3-O-Diferuloylglycerol	443.132	9.22	[M−H]−	neg	C23H24O9	4.20 × 10−11	0.4	2.53 × 10−26	0.3	HCA
Caffeic acid derivative	475.143	1.92	[M−H]−	neg	C20M28O13	1.81 × 10−15	1.5	2.56 × 10−17	2.5	HCA
1,2-bis-O-Sinapoyl-beta-d-glucoside	591.166	6.19	[M−H]−	neg	C28H32O14	0.547	1.0	0.105	1.0	HCA
Indole-3-acrylic acid/N-Ac-indole-3-carboxyaldehyde	188.076	2.71	[M+H]+	pos	C11H9NO2	2.12 × 10−27	0.5	1.85 × 10−18	0.5	Indole
Methyl indole-3-acetate	190.085	2.69	[M+H]+	pos	C11H11NO2	4.47 × 10−11	0.5	4.33 × 10−9	0.5	Indole
Indole-3-pyruvate	202.051	7.89	[M−H]−	neg	C11H9NO3	3.07 × 10−18	1.9	5.79 × 10−13	2.5	Indole
6-Hydroxy-indole-3-acetyl-valine	289.119	3.95	[M−H]−	neg	C15H18N2O4	1.83 × 10−9	1.7	0.469	0.9	Indole
Indole-3-acetyl-leucine	333.120	3.25	[M+H_NaNa]+	pos	C16H20N2O3	1.45 × 10−7	4.1	0.001	1.9	Indole
Indole-3-yl-acetyl-myo-inositol l-arabinoside	468.152	3.13	[M−H]−	neg	C21H27NO11	0.000	1.3	0.117	0.9	Indole
DIMBOA-Glc	372.093	1.58	[M−H]−	neg	C15H19NO10	0.001	0.8	9.77 × 10−14	0.4	Benzoxazine
Isocitric acid	191.018	1.10	[M−H]−	neg	C6H8O7	5.97 × 10−14	2.3	1.64 × 10−9	1.6	Carboxylic acid
Octadecatetraenoic acid	275.200	13.44	[M−H]−	neg	C18H28O2	1.64 × 10−17	4.1	1.20 × 10−11	3.6	Fatty acid
16-Hydroxypalmitate	271.044	13.43	[M−H]−	neg	C16H31O3	8.38 × 10−19	4.9	9.55 × 10−13	4.1	Fatty acid
15-Hydroxylinoleic acid	295.226	14.3	[M−H]−	neg	C18H32O3	1.38 × 10−18	3.6	8.76 × 10−14	3.4	Fatty acid
10,16-Dihydroxypalmitate	287.075	10.24	[M−H]−	neg	C16H31O4	9.76 × 10−14	8.0	6.75 × 10−11	8.1	Fatty acid
Dihydroxy-octadecadienoic acid	311.220	11.81	[M−H]−	neg	C18H32O4	5.87 × 10−17	4.9	2.18 × 10−11	6.0	Fatty acid
11,12,13-Trihydroxy-9,15-octadecadienoic acid	327.215	9.06	[M−H]−	neg	C18H32O5	1.95 × 10−32	2.7	1.30 × 10−5	1.5	Fatty acid
9,12,13-Trihydroxy-10-octadecenoic acid	329.229	9.60	[M−H]−	neg	C18H34O5	3.23 × 10−27	2.5	3.95 × 10−17	2.0	Fatty acid
Salicylic acid	137.031	3.69	[M−H]−	neg	C7H6O3	4.29 × 10−12	1.3	0.091	3.9	Phytohormone
Salicylic acid 2-O-beta-d-glucoside	299.074	1.62	[M−H]−	neg	C13H16O8	7.21 × 10−17	1.7	9.28 × 10−24	1.9	Phytohormone
Jasmonoyl-l-isoleucine	322.010	4.16	[M−H]−	neg	C18H29NO4	2.94 × 10−12	0.5	5.03 × 10−20	0.1	Phytohormone
Dihydrozeatin-9-N-glucoside-O-glucoside	544.208	2.80	[M−H]−	neg	C22H35N5O11	0.001	0.8	4.22 × 10−12	2.8	Phytohormone
Zeatin riboside	352.183	3.16	[M+H]+	pos	C15H21N5O5	1.35 × 10−28	0.3	3.27 × 10−22	0.4	Phytohormone
Chorismic acid	225.040	2.61	[M−H]−	neg	C10H10O6	nd	nd	0.076	0.9	Shikimate
Caffeoylshikimic acid	335.076	4.64	[M−H]−	neg	C16H16O8	2.89 × 10−17	0.3	3.84 × 10−11	0.3	Shikimate/HCA

nd: not detected in the cultivar; p-values refer to significance level of metabolites. Fold change was calculated by dividing the average of the metabolite peak intensity values in replicate samples of ‘infected’ by the average of the metabolite intensity values in replicate samples of ‘control’, a value >1 represents an increase (metabolite is higher in the infected samples than in the control) and value <1 represents a decrease (metabolite is higher in the control and infection led to decrease in levels). HCA: hydroxycinnamic acid.