were demonstrated to yield a wealth of biologically active metabolites, exemplified as sterols, sesquiterpene aryl esters, and many other components exhibiting therapeutic or dietary values [17; 18; 19]. Thus, it is obligated to fully elucidate the molecular basis or mechanism of _Armillaria_ at the genomic level. The technological revolution in genome sequencing and bioinformatics have markedly increased the number of sequenced Basidiomycetous genomes. There are already nine _Armillaria_ genomes that have been published to date, and those for _A. mellea_ DSM3731, _A. ostoyae_ C18/9, _A. solidiges_ 28-4, _A. borealis_ FPL87.14 v1.0, _A. fuscipes_ CMW2740, _A. cepistipes_ B5, _A. altimontana_ 837-10, two _A. gallica_ strains Ar21-2 and 012m were included. Analyses of these genomic and transcriptomic information have provided insights into evolution, genetics, developmental biology, plant-cell-wall-degrading enzymes (PCWDE) repertoire, and related pathogenicity factors [20; 21; 22; 23; 24]. [PERSON] and coworkers performed omics sequencing to provide genetic and regulatory insights into toolkits for wood-decaying, morphogenesis and complex multicellularity including rhizomorph and fruiting bodies development of the strain _A. ostoyae_ C18 [23]. The taxonomy of _Armillaria_ has raised controversial debate, recently, _Armillaria_ was narrowed down to include only annulate species, and _Desarmillaria_ was introduced to accommodate two exannulate mushroom-forming armillarioid species (_D. cetypa_ and _D. tabescens_) [25; 26]. The lineage to diverge is that composed of annulate mushroom-forming armillarioid species, in what _A. mellea_ (Vahl: Fr.) [PERSON] is the type species [27]. [PERSON] et al. (2017) conducted six-locus phylogenetic analysis among _Armillaria_ and related affinities, demonstrated that _Guyanagaster_ and _Desarmillaria_ are close lineages [25]. On the delimitation and characterization of _Armillaria_ species, the genome-based phylogenomics and comparative genomics were invaluable to understand the phylogeny of _Armillaria_ and sister groups. In this study, we report a 50.36 Mb draft genome sequence of _D. tabescens_ CPCC 401429. MLST-based phylogeny and synteny analysis at the genomic level were investigated, which reinforced that the _D. tabescens_ was supposed to belong to the genus of _Desarmillaria_ instead of _Armillaria_ as it used to. Genome profiling and transcript on three different fermentation conditions shed light on the secondary metabolism. Notably, guided by STSs phylogeny based predictive framework, a diverse network of twelve putative sesquiterpene biosynthetic genes were obtained and half of them were categorized into the new subfamily, i.e., diverse Clade IV. Intriguingly, two genes including _DtSTS9_ and _DtSTS10_ were codon optimized and cloned for heterologous expression in yeast host. Through gas chromatography-mass spectrometry (GC-MS) analysis, yeast cells expressing DtSTS9 and DtSTS10 produce diverse sesquiterpenes. This work provides the genomic basis to understand and investigate the new genus _Desarmillaria_. We exemplify the exploitation on uncharacterized STSs of basidiomycetes and help to broaden our knowledge of sesquiterpenes biosynthesis.