## 4 Discussion  
In this research, the most commonly isolated genus was _Penicillium_. Several of them, such as _P. brasilanum_ and _P. cosmopolitanum_, were isolated from multiple locations, while _P. canscensens_, _P. manginii_, _P. scabrosum_, and _P. virgatum_ were isolated from only one location. These data may indicate that while the genus is considered cosmopolitan, not all individual species are ubiquitous. Since the _Penicillium_ genus is one of the most common fungi found in rhizosphere soil, it is suspected to overshadow the results [52], as it interacts positively  
Figure 4: The values of the Shannon Diversity Index calculated for individual research sites (I–XI) obtained using the hair bait method (keratinophilic and keratinocyte fungi), PDA medium (fungi generally), and overall for both methods (all fungal species). with crop roots and enhances their growth. Some species exhibit antagonistic activities against plant pathogens by producing antibiotics [53]. For instance, _P. ochrdochloron_ is known for producing antibiotic molecules with high activity against multidrug-resistant bacteria [54]. Most species, however, are of dual environmental importance. On the one hand, the genus contains many species that are considered plant endophytes and are adroit at producing an extensive span of different active compounds that might have conceivable applications in the fields of biotechnology or medicine (such as isolated _P. virgatum, P. canescens, P. subrubescens_, and _P. brasiliensis_) [55; 56; 31; 57]. On the other hand, some species are capable of producing harmful mycotoxinsoxins, which may cause food spoilage or crop damage [57]. _Penicillium_ spp. spores commonly appearing in the environment in relatively large quantities are known as strong risk factors for asthma [58]. _Penicillium_ spp. are some of the most predominant molds isolated from contaminated buildings with the so-called sick building syndrome (SBS) [59]. The majority of isolated species pertaining to this genus was _P. brasilianum_. The most of _P. brasilianum_ strains reported in the literature are isolated from soil [57] and can cause losses in onion crops [60]. Additionally, this species can be considered an etiological factor in various human diseases. There is a report of a case of thumbnail infection in a patient living with HIV-1, including _P. brasilianum_[61]. Other species like _P. chrysogenum_ that were isolated from the soil samples can also cause invasive infections in immunocompromised patients [62; 63], including children [64]. Alarmingly, the first case of meningoencephalitis caused by _P. chrysogenum_ was found in a patient previously considered immunocompetent and was recently described [65]. It should be noted that currently there is no antifungal remedy of choice for the management of penicillin [64]. Incorporating the general culture method with a PDA medium allowed for the isolation of a greater quantity of keratin-independent species common in the soil. _Trichoderma hamatum_ and _T. virens_, identified in the study, represent the widely distributed _Trichoderma_ genus in soil. _Trichoderma_ has the ability to colonize plant roots; therefore, it has a promising prospect in the field of agriculture, especially in the context of biocontrol against the wide range of soil phytopathogens [66]. _Pochonia bullibosa_, _Lecanicillium psaltiotae_, _Clonostachys solani_, and _C. rosea_ are recognized as entomopathogenic fungi [67; 68; 69]. _P. bullibosa_ can produce urease [70], whereas _L. psaltiotae_ has the capability to produce antibiotic and antifungal compounds [71]. On the other hand, _Linnemannia elongata_ (basionym: _Morierella elongata_) can decompose various toxic organic substances, potentially improving soil conditions and positively affecting plant development [72; 73]. Another group of fungi cultivated and isolated from the soil samples consisted of keratinophilic/keratinolytic species obtained by the hair bait method.