## 2 Results
The rest six FA-derived VOCs showed lower abundances (\(<\)3.1) with no significant differences between the genotypes or between treatments. Similar trends, although at much-reduced abundance were also observed in the norisoprenoid, \(\beta\)-Ionone while the rest of the species in this group did not show any significant differences between the test groups, suggesting that the FA-derived (H)-2-hexenal and hexanal and the norisoprenoid, \(\beta\)-Ionone, maybe the three main volatile metabolites in this study that were associated with resistance against the pathogen Lso. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c}  & \multicolumn{1}{c}{**No. **} & \multicolumn{1}{c}{**ET**} & \multicolumn{1}{c}{**Compounds**} & \multicolumn{1}{c}{**Class of Volatile**} & \multicolumn{1}{c}{**KI**} & \multicolumn{1}{c}{**ID**} & \multicolumn{1}{c}{**CM**} & \multicolumn{1}{c}{**CM**} & \multicolumn{1}{c}{**L2**} & \multicolumn{1}{c}{**L3**} \\ \cline{6-13}  & & & & & & & & & & & & & & & \\ \hline \hline \multicolumn{1}{c}{} & 4.63 & Heemal & Forty-addressed & 800 & MR, NI, NI & 10. For the mean PA-derived group showing down-regulation in resistant LA_TPP-Lso(\(-\)) and LA_TPP-Lso(\(+\)), four out of five compounds had their abundances significantly lower in the two treatments compared to all the other treatments in CM and LA_Control. Methyl-salicylate showed the most notable abundance which was at a high of 10.17 \(\pm\) 1.52 (CM_Control), 9.38 \(\pm\) 1.08 CM_TPP-Lso(\(-\)), 7.22 \(\pm\) 1.14 CM_TPP-Lso(\(+\)) and 5.99 \(\pm\) 0.63 for LA_Control and a significantly reduced abundance of 2.78 \(\pm\) 0.47 in LA_TPP-Lso(\(-\)) and 2.76 \(\pm\) 0.22 in LA_TPP-Lso(\(+\)). Other compounds, namely eugenol, benzophenone, and benzothiazole, showed a very similar trend, albeit at significantly lower corresponding abundances, suggesting that these compounds may be  
Figure 5: Volatile metabolite abundance in Control, TPP-Lso(\(-\)), and TPP-Lso(\(+\)) infested tomato plants, CastleMart (CM), and RIL LA3952 (LA), respectively. (**A**) monoterpenes (**B**) sesquiterpenes (**C**) fatty acid-derived (**D**) norisoterpenoid (**E**) phenylpropanoids (PA)-derived. Bar graphs indicate the mean total abundance of detected compounds in each chemical class. Three-dimensional (3D) sparse partial least square-discriminant analysis (sPLS-DA) scores plots of (**F**) insect-susceptible (CM) and (**G**) insect-resistant (LA) tomato plants demonstrate that each tomato variety can be separated into distinct groups without overlap according to the treatment [Blue dots, TPP-Lso(\(+\)); green, TPP-Lso(\(-\)), and red, mock-infested control]. The heatmaps show the effect of treatment on the mean abundance of studied metabolites within groups based on tomato varieties such as CM (**H**) and LA (**I**). The scale legend of the heatmap indicates the relative abundance of volatile metabolites in each chemical group. \({}^{*}\), \({}^{**}\), and \({}^{**}\) denote significant at \(p\leq\) 0.05, \(\leq\) 0.01, and \(\leq\) 0.001, respectively; n.s., not significant. influenced by susceptibility factors induced during TTP feeding or Lso interaction in the susceptible CM plants. Among the 14 monoterpenes, only \(\beta\)-phellandrene showed significant difference in abundance, which was between CM_TPP-Lso(-) (701.74 \(\pm\) 75.28) and all the other treatment sets: 476.35 \(\pm\) 40.23 in CM_Control, 519.46 \(\pm\) 74.65 in CM_TPP-Lso(+), 538.26 \(\pm\) 51.54 LA_Control, 503.77 \(\pm\) 39.98 in LA_TPP-Lso(-), and 493.63\(\pm\)47.56 in LA_TPP-Lso(+). This suggests that \(\beta\)-Phellandrene is not only ubiquitously abundant but may be a marker for insect susceptibility in the CM. Similar trends though at much-reduced and insignificant differences in abundance were observed in the sesquiterpene, \(\beta\)-Caryophyllene.