Fig. 8

Terpene accumulation pattern after infection. a Total terpenes in the genotypes PRA-R, PRA-A, PRA-B and PRA-D at different time points. Note that PRA-R accumulated less terpenes at earlier time points, and that this difference decreased with needle age. b Hierarchical cluster analysis of terpene content from 7 to 29 dpi. Colours in the heat map represent the log2 ratio, according to the scale shown at the bottom. Green dots designate monoterpenes, red dots apocarotenoids and purple dots sesquiterpenes. c Terpene abundance, represented as log2 ratio referred to the reference mix, for metabolites belonging to groups 1 and 2 (shown in panel B). Note that sesquiterpenes are less abundant in PRA-R at all time points. Asterisks represent statistically significant difference (Ttest, pvalue < 0.05) between each genotype and PRA-R total terpene content