Trans-enoyl reductase; part of the gene cluster that mediates the biosynthesis of tenellin-type 2-pyridones, iron-chelating compounds involved in iron stress tolerance, competition with the natural competitor fungus Metarhizium robertsii and insect hosts infection (PubMed:17216664, PubMed:18266306, PubMed:20575135, PubMed:34903054). TenC collaborates with the hybrid PKS-NRPS synthetase tenS to catalyze the assembly of the polyketide-amino acid backbone, since tenS lacks a designated enoylreductase (ER) domain (PubMed:18266306, PubMed:34903054). Upon formation of the polyketide backbone on the thiotemplate of tenS, the triketide is transferred to the NRPS module and linked to tyrosine to produce the pyrrolidine-2-dione intermediates, including pretellinin A, 11-hydropretellenin A, 12-hydropretellenin A, 13-hydropretellenin A, 14-hydropretellenin A, 12-oxopretellenin A and prototellinin D (PubMed:18266306, PubMed:34903054). The pathway begins with the assembly of the polyketide-amino acid backbone by the hybrid PKS-NRPS tenS with the help of the enoyl reductase tenC. These enzymes catalyze the synthesis of the pyrrolidine-2-dione intermediates pretellinin A, 11-hydropretellenin A, 12-hydropretellenin A, 13-hydropretellenin A, 14-hydropretellenin A, 12-oxopretellenin A and prototellinin D. The cytochrome P450 monooxygenase tenA then catalyzes an oxidative ring expansion of pretenellin A and 14-hydropretellenin A to form the 2-pyridone core, leading to pretenellin B and pyridovericin, respectively. The cytochrome P450 monooxygenase tenB is then required for the selective N-hydroxylation of the 2-pyridone nitrogen of yield tellinin and 15-hydroxytellenin (15-HT), respectively. The UDP-glucosyltransferase GT1 and the methyltransferase MT1, located outside the tenS gene cluster, contribute to the stepwise glycosylation and methylation of 15-HT to obtain the glycoside pyridovericin-N-O-(4-O-methyl-beta-D-glucopyranoside) (PMGP). Additional related compounds such as 1-O-methyl-15-HT, (8Z)-1-O-methyl-15-HT, and O-methyltenellin A are also produced but the enzymes involved in their biosynthesis have still to be determined (PubMed:34903054). Secondary metabolite biosynthesis. Monomer. Expression is positively regulated by the cluster-specific transcription factor tenR and is induced during cocultures with the natural competitor fungus Metarhizium robertsii. Belongs to the zinc-containing alcohol dehydrogenase family.