Mechanism and regulation of sorbicillin biosynthesis by Penicillium chrysogenum

Abstract

Summary Penicillium chrysogenum is a filamentous fungus that is used to produce β‐lactams at an industrial scale. At an early stage of classical strain improvement, the ability to produce the yellow‐coloured sorbicillinoids was lost through mutation. Sorbicillinoids are highly bioactive of great pharmaceutical interest. By repair of a critical mutation in one of the two polyketide synthases in an industrial P. chrysogenum strain, sorbicillinoid production was restored at high levels. Using this strain, the sorbicillin biosynthesis pathway was elucidated through gene deletion, overexpression and metabolite profiling. The polyketide synthase enzymes SorA and SorB are required to generate the key intermediates sorbicillin and dihydrosorbicillin, which are subsequently converted to (dihydro)sorbillinol by the FAD‐dependent monooxygenase SorC and into the final product oxosorbicillinol by the oxidoreductase SorD. Deletion of either of the two pks genes not only impacted the overall production but also strongly reduce the expression of the pathway genes. Expression is regulated through the interplay of two transcriptional regulators: SorR1 and SorR2. SorR1 acts as a transcriptional activator, while SorR2 controls the expression of sorR1. Furthermore, the sorbicillinoid pathway is regulated through a novel autoinduction mechanism where sorbicillinoids activate transcription.

Functional analysis of polyketide synthase genes in the biocontrol fungus Clonostachys rosea

“…purpureus 50 and T. reesei 41 , 51 . For instance, C. rosea is predicted to harbour orthologs of the sorbicillinoid family-type yellow pigment sorbicillin ( pks2 and pks12 ) gene cluster 52 , 53 , conserved and functionally active in several distantly related fungi such as Acremonium chrysogenum , P. chrysogenum , T. reesei , Chaetomium globosum and Colletotrichum graminicola 30 , 51 . In addition, C .…”

Diels–Alder Reactions During the Biosynthesis of Sorbicillinoids

“…LCMS chromatograms obtained from + sorABD transformants ( Figure 2G)d id not significantly differ from those for + sorAB transformants,thus indicating that 2a and 2bare the required substrates for SorD.T he observation of both 1a and 1b in these transformants indicates that SorD does not oxidize 1b to 1a as proposed by Derntl et al [21] Similarly, since the oxosorbicillinols 9aand 9bwere not observed in any of the chromatograms,SorD does not seem to have arole in oxidizing 2 to 9 as proposed by Guzmµn-Chµvez et al [22] This shows that SorD has two roles:d imerization of 2 to 3 and 4, which does not require oxidation of 2,a nd an independent role in oxidizing 2a/b to epoxides 10 a/b.…”

“…[20] Theonly other confirmed homologous sorbicillinoid BGC exists in T. reesei QM6a [21] and shares the three core genes sorA, sorB and sorC required for formation of 2 (Scheme 1E). [9,[20][21][22] The T. reesei BGC also encodes asecond FMO named SorD.D erntl et al [21] proposed that T. reesei SorD catalyses the oxidation of 1b to 1a (Scheme 1F). In contrast, Guzmµn-Chµvez et al [22] suggested that P. chrysogenum SorD catalyses the oxidation of 2a into oxosorbicillinol 9a (Scheme 1F), since increased amounts of 2a were produced by their DsorD strain.…”

“…[9,[20][21][22] The T. reesei BGC also encodes asecond FMO named SorD.D erntl et al [21] proposed that T. reesei SorD catalyses the oxidation of 1b to 1a (Scheme 1F). In contrast, Guzmµn-Chµvez et al [22] suggested that P. chrysogenum SorD catalyses the oxidation of 2a into oxosorbicillinol 9a (Scheme 1F), since increased amounts of 2a were produced by their DsorD strain. ARTEMIS analysis shows that the two sorD genes are not homologous (Scheme 1E), thus indicating that they may catalyse different reactions in T. reesei and P. chrysogenum,despite both fungi synthesizing asimilar variety of sorbicillinoids.…”

Exploring the Extracellular Macromolecular Composition of Crude Extracts of Penicillium rubens Strain 212 for Elucidation Its Mode of Action as a Biocontrol Agent

“…Pyrogallol-type phenolic compounds have three adjacent hydroxyl groups on the same benzene ring, which enables their easy oxidation or autoxidation and also allows metal ion chelation, both characteristics contributing significantly to a wide range of biological activities [ 81 ]. Finally, sorbicillinoids are secondary metabolites with anti-inflammatory and antimicrobial activities produced by filamentous fungi [ 82 ].…”