FIGURE 4.

Relative expression of terpene biosynthetic genes before and after Endoconidiophora polonica infection. The expression of isoprenyl diphosphate synthase 1 (IDS1), IDS 4, IDS5, and various terpene synthases (diterpene synthases, δ-3-carene synthase, α/β-pinene synthase, α-bisabolene synthase, and longifolene synthase) were measured by quantitative real-time PCR analysis from bark tissue harvested before and 14 days after infection with E. polonica. Trees investigated: (1) were from a stand with a history of previous bark beetle attack, but no current attack (PA), (2) were under current attack, but had no previous history of attack (CA), or (3) had no previous nor current attack (NA). Different letters indicate significant differences. Data are means ± SD of measurements from 6 to 12 biological replicates; exact numbers are given in the Section “Materials and Methods.” Statistical values for individual compounds are given in Supplementary Table 6.