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Table 2 Significant metabolites according to the random forest models

From: Natural variation in wild tomato trichomes; selecting metabolites that contribute to insect resistance using a random forest approach

Metabolite

m/z

Experimental KI

Theoretical KI

Insect

Classification

P-value

S3:15

617 [M + Na]+

–

–

whitefly

resistance

p < 0.001

S3:21

715 [M + Na]+

–

–

whitefly

resistance

p < 0.001

α-humulene

204.2

1457

1454

whitefly

susceptibility

p < 0.001

α-phellandrenea

136.1

1000

1002

thrips

susceptibility

p < 0.001

α-terpinenea

136.1

1013

1017

thrips

susceptibility

p < 0.001

β-phellandrene/D-limonene

136.1

1027

1029

thrips

susceptibility

p < 0.001

  1. Acylsugars are annotated by their sucrose (S) or glucose (G) backbone followed by the number of acyl chains and the number of carbon atoms distributed over the acyl chains. Volatiles were annotated using the Kovats Retention Index (KI) and fragmentation-pattern comparison to the Adams [46] and NIST libraries. The table provides the resistance/susceptibility classification for the different insects by the RF model and the p-value indicates whether the calculated feature importance significantly deviates from a randomly permuted model (threshold: p < 0.05). a Metabolite annotation confirmed by an analytical standard. The β-phellandrene/D-limonene peak could not be separated due to their strong co-elution. Mass spectra of metabolites not verified by an analytical standard are given in Additional file: Figure S8.