Diterpene gene cluster involved in abietane-type diterpenoids in
S. rosmarinus
Comparisons of microsynteny blocks detected in S. rosmarinus ,S. miltiorrhiza and S. splendens , revealed the presence of
two diterpene gene clusters (DGC) in S. rosmarinus distributed in
Chr1 and Chr2, spanning 220 Kb and 200 Kb, respectively (Figure S27).
Previous studies have reported the loss of shoot KSL and
three CYP76AH genes (CYP76AH59 , CYP76AH58 , andCYP76AH56 ) in S. militiorrhiza DGC, and silencing or
inactivity of SmCPS2 in tanshinone biosynthesis, leading to the
abrogation of abietane-type diterpenoid biosynthesis in shoots (C.-Y. Li
et al., 2022). Despite the loss of CYP76AH59 on rosemary
chromosomes, SrCYP76AH58 , SrCYP76AH56 , SrCPS , andSrKSL were identified in the rosemary DGC, providing precursors
for abietane-type diterpenoid biosynthesis. CPS2 had been
silenced in DGCS of S. miltiorrhiza and rosemary, however,SrCPS1 on Chr1 and Chr2 highly expressed in rosemary leaves
(4.03-fold and 6.42-fold), and remained active in diterpene
biosynthesis. HPLC-MS results also revealed that the accumulation of
carnosic acid and carnosolin rosemary leaves. These findings demonstrate
that the, two DGCs in rosemary retain the ability of produce
abietane-type diterpenoids in its leaves.