In summary, we report here that (i) spirotoamides and TTN are biosynthesized in S. griseochromogenes by two distinct type I PKSs, competing for the same pool of acyl-CoA precursors, with TTN as the dominant metabolite under the fermentation conditions examined, (ii) the biosynthesis of spirotoamides and TTN are co-regulated by TtnQ, a transcriptional activator previously characterized from the ttn cluster, and cross-talk among pathway-specific regulators for secondary metabolite biosynthesis could potentially be exploited to activate cryptic gene clusters for the discovery of new natural products, and (iii) spirotoamide production can be significantly increased upon inactivation of the TTN biosynthetic machinery, leading to the isolation and structural elucidation of two new analogues, named spirotoamide C (3) and D (4), together with the known spirotoamide A, none of which, however, showed any antibacterial activity against the selected Gram-positive and Gram-negative bacteria.