## 3 _Apergillus_ Is a Microbial Chassis for Natural Product Synthesis
### A. oryzae Is a Chassis for Natural Product Production
#### 3.1.2 The Production of Terpenoids in _A. oryzae_
characterized 12 putative sesquiterpene synthases and one P450 enzyme in basidiomycete_Flammulina velutipes_, ultimately leading to the biosynthesis of 16 distinct sesquiterpenoid compounds [87]. Diterpenoids  
Diterpenoids, composed of four isoprene units, are a diverse class of natural products biosynthesized from the C20 precursor GGPP. They have high value in the pharmaceutical industry and exhibit diverse biological activities, including antitumor, anti-inflammatory, and immunosuppressive effects [88; 89]. [PERSON] et al. successfully introduced the whole gene cluster into _A. oryzae_ by using four different vectors and demonstrated the total biosynthesis of a typical diterpene aphidicolin [90]. [PERSON] et al. identified an unusual chimeric terpene synthase (EvVS) by genome mining of the fungus _Enteriella variecolor_. Through heterologous expression in _A. oryzae_, a novel tricyclic diterpene hydrocarbon, variadiene, was successfully obtained [91]. Furthermore, [PERSON] et al. achieved the biosynthesis of the biologically active compound pleurmutilin using _A. oryzae_ as a heterologous host [21]. In 2017, based on the previous research, [PERSON] et al. gradually expressed the biosynthetic gene of pleurmutilin in _A. oryzae_ and finally revealed its complete biosynthetic pathway [92]. In recent years, employing heterologous hosts of _A. oryzae_, integrated with pathway engineering methodologies, researchers have obtained new pleurmutilin congeners with antimicrobial activities, which provide more options for the expansion of this  
Figure 2: Metabolism pathway for terpenoid production in _A. oryzae_. HXK, hexokinase; PGI, phosphoglucose isomerase; PFK, phosphofructokinase; FBA, fructose-bisphosphate aldolase; TPI, triose phosphate isomerase; TDH, glyceraldehyde-3-phosphate dehydrogenase; PGK, phosphoglycerate kinase; GPM, phosphoglycerate mutase; ENO, enolase; PKI, pyruvate kinase; PDC, pyruvate decarboxylase; ADH, alcohol dehydrogenase; ALD, aldehyde dehydrogenase; ACS, acetyl-CoA synthase; ACC, acetyl-CoA carboxylase; ERG10, acetyl-CoA C-acetyltransferase; ERG13, hydroxymethylglutaryl-CoA synthase; HMGR, HMG-CoA reductase; ERG12, mexolonate kinase; ERG8, phosphohexulonate kinase; ERG19, diphosphomevalonate decarboxylase; IDI, Isopentenyl-diphosphate delta-isomerase; ERG20, FPP synthase; ERG9, squalene synthase; PDH, pyruvate dehydrogenase; CIT, citrate synthase; ACO, aconitase; IDH, isocitate dehydrogenase; KGD, multifunctional 2-oxoglutarate metabolism enzyme; ISC, succinyl coenzyme A synthetase; SDH, succinatedehydes; FUM, fumarase; MDH, malate dehydrogenase; IPP, isopentenyl pyrophosphate; DMAPP, dimethylallyl pyrophosphate; GPP, geranyl diphosphate; FPP, famesyl pyrophosphate. family of drugs [93; 94; 95]. Notably, [PERSON] et al. obtained an _A. oryzae_ strain generated by engineering multiple metabolic pathways, containing 13 metabolic modifications, which showed excellent productivities of pleuromutilin (161.6 mg/L), an 8.5-fold increase compared to the control strains without any metabolic modifications [96]. Additionally, [PERSON] et al. employed an _A. oryzae_ expression system to reconstruct the biosynthetic pathway of brassicienes, which are a series of diterpenes, and the generated transformant successfully biosynthesized novel brassiciene derivatives (brassiciene I) [97]. Moreover, by using a newly developed hot-spot knock-in and plasmid recycling genome editing method, [PERSON] et al. reconstituted the biosynthetic gene cluster of erinacine (a bioactive diterpene) in _A. oryzae_, which generated erinacine Q and its intermediates [67]. Very recently, [PERSON] et al. identified a novel biosynthetic gene cluster (_tdn_) by using a genome mining method in _Talaromyces adpressus_ and achieved heterologous expression of _tdn_ genes in _A. oryzae_. As a result, a new diterpenoid, cycloaraneosene-9-ol-8-one, and three known diterpenoids were determined [98].