Anthrone oxygenase; part of the gene cluster that mediates the biosynthesis of geodin, an intermediate in the biosynthesis of other natural products (PubMed:7665560, PubMed:19549600, PubMed:24009710). The pathway begins with the synthesis of atrochrysone thioester by the polyketide synthase (PKS) gedC (PubMed:12536215, PubMed:19549600). The atrochrysone carboxyl ACP thioesterase gedB then breaks the thioester bond and releases the atrochrysone carboxylic acid from gedC (PubMed:19549600). The atrochrysone carboxylic acid is then converted to atrochrysone which is further transformed into emodin anthrone (PubMed:24009710). The next step is performed by the emodin anthrone oxygenase gedH that catalyzes the oxidation of emodinanthrone to emodin (PubMed:1810248). Emodin O-methyltransferase encoded probably by gedA then catalyzes methylation of the 8-hydroxy group of emodin to form questin (PubMed:1444712). Ring cleavage of questin by questin oxidase gedK leads to desmethylsulochrin via several intermediates including questin epoxide (PubMed:3182756). Another methylation step probably catalyzed by methyltransferase gedG leads to the formation of sulochrin which is further converted to dihydrogeodin by the sulochrin halogenase gedL (PubMed:24009710). Finally, the dihydrogeodin oxidase gedJ catalyzes the stereospecific phenol oxidative coupling reaction converting dihydrogeodin to geodin (PubMed:7665560). emodin anthrone + O2 = emodin + H(+) + H2O Secondary metabolite biosynthesis. Belongs to the anthrone oxygenase family. The predicted gene ATEG_08457 has been split into 2 genes: ATEG_08457-1 and ATEG_08457-2.