Fig. 7.
Proposed biosynthesis of indole diterpenes in A. flavus. Two indole diterpene cyclases (AtmB and AfB) work in conjunction with the epoxidase AtmM to produce diverse chemical structures from a common intermediate. Genes encoding for biosynthesis of the epoxide intermediate (AtmG, AtmC, and AtmM) are clustered together (ATM1). Genes encoding for biosynthesis of paspaline, paspalinine, and aflatrem (AtmB, AtmP, AtmQ and AtmD) are also clustered together (ATM2), while the gene encoding AfB, responsible for aflavinine biosynthesis, is not clustered with either ATM1 or ATM2. Adapted from Nicholson et al.140) and Tang et al.151).