## 3 Results and Discussion
### Genomic Characteristics
The top five most representative (1) families were as follows: (IPR027417) P-loop containing nucleoside triphosphate hydrolase, (IPR036259) MFS transporter superfamily, (IPR036291) NAD(P)-binding domain superfamily, (IPR011009) protein kinase-like domain superfamily and (IPR011701) major facilitator superfamily; (2) the domains were as follows: (IPR020846) major facilitator superfamily domain, (IPR001138) Zn(2)-C6 fungal-type DNA-binding domain, (IPR007219) transcription factor domain, fungi, (IPR000719) protein kinase domain and (IPR003593) AAA+ ATPase domain; (3) the sites  
Figure 5: Gene Ontology (GO) terms count for the top 10 most representative GO terms (i.e., for biological processes, cellular components and molecular function) in the genome annotation. were as follows: (IPR008271) serine/threonine-protein kinase, active site, (IPR005829) sugar transporter, conserved site, (IPR017441) protein kinase, ATP binding site, (IPR020904) short-chain dehydrogenase/reductase, conserved site and (IPR019775) WD40 repeat, conserved site; and (4) the repeats were as follows: (IPR001680) WD40 repeat, (IPR002110) Ankyrin repeat, (IPR019734) tetratricopeptide repeat, (IPR020472) G-protein beta WD-40 repeat and (IPR018108) mitochondrial substrate/solute carrier (Figure 6). In previous works [65; 66; 67], high levels of major facilitator transporters (MFS), Zn (2)-C6 fungal-type DNA-binding domains (IPR001138), fungal transcription factor domain (IPR007219) and sugar transporters conserved sites (IPR017441), have been found to be sturdily represented in stress-tolerant or adapted fungal species, such as _Hortaae wereckii_, _Friedmanniumyces endidilicus_, _Aeminium ludgeri_, _Saxispiralis lemonorum_ and _Penicillium pancrosimum_. They have been commonly associated with the transportation of small solutes in response to chemiosomic ion gradients, resistance to toxic compounds and allow the functionality of metabolic systems in extreme environments [65; 66; 67; 68]. Their detection is, thus, in line with common responses to the environment from where the _Penicillium mexicanum_ strains were retrieved. Moreover, the dominant presence of (IPR027417) P-loop containing nucleoside triphosphate hydrolase is also relevant since multiple NTPasses are metalloenzymes/metallochaperones interacting and transporting metal ions [69] and can consequently play important roles towards the proper cell functioning of _Penicillium mexicacum_ in these contaminated environments. The OmicsBox enzyme coding mapping tool highlighted that the most prevalent enzyme types predicted in the genome were hydrolases, transferases and oxidoreductase (Supplementary Table S2). In parallel, the Eggnog mapper revealed that the top five most relevant Clusters of Orthologous Genes (COGs) category groups were as follows: [S] function unknown, [G] carbohydrate transport and metabolism, [E] amino acid transport and metabolism, [O] post-translational modification, protein turnover, chaperones and [U] intracellular trafficking, secretion, and vesicular transport (Figure 7). The high number of hydrolases, transferases and oxidoreductase, coupled with a strong representation of [G] carbohydrate transport and metabolism and [E] amino acid transport and metabolism, highlights both the species saprotrophic nature but also the main metabolic features and requirements contributing to their survival in mining soils. Figure 6: InterProScan terms count for the top 10 most representative protein families, domains, sites and repeats found in the genome annotation. Complementarily, the dbCAN3 software identified 1694 carbohydrate-active enzymes (CAZomes), with a high dominance of glycoside hydrolases (GHs) and glycostransferases (GTs); intermediary numbers for auxiliary activities (AAs), carbohydrate-binding modules (CBMs) and carbohydrate esterases (CEs); and rather low numbers of polysaccharide lysates (PLs) (Supplementary Table S3).