## 5 Conclusions and Perspectives  
With the rapid development of synthetic biology and molecular biology techniques, _Aspergillus_ species exhibit substantial potential as expression hosts and play an increasingly vital role in the heterologous production of proteins and the synthesis of bioactive natural products. On the one hand, the engineered strains of _Aspergillus_ enable the efficient production of heterologous proteins, significantly increasing their yields to meet industrial standards [24]. On the other hand, as an extraordinary chassis, _Aspergillus_ can activate silent biosynthetic gene clusters (BGCs), facilitating the discovery of novel natural products, as well as promoting the elucidation of complete biosynthetic pathways, thus simplifying and optimizing their intricate synthesis routes [161]. For instance, _A. oryzae_, _A. niger_, and _A. nidulans_ are being widely developed as research tools in synthetic biology [162; 163]. Notably, _A. oryzae_ serves as a powerful platform that not only enables rapid and efficient functional identification of natural product biosynthetic gene clusters but also facilitates genome-guided mining of bioactive natural products. Moreover, this system can be exploited for targeted engineering and optimization of functional genes to enhance natural product biosynthesis [58; 80]. To date, _A. oryzae_ has successfully enabled the heterologous expression of diverse natural product classes, particularly sesquiterpenoids, triterpenoids, and polyketides (PKs) [164; 79; 165]. Remarkably, this platform exhibits outstanding adaptability, efficiently integrating biosynthetic genes not only from filamentous fungi but also from basidiomycetes, bacteria, and even higher plants [166; 167]. Such versatility has significantly accelerated the rapid elucidation and reconstruction of biosynthetic pathways for complex natural products, establishing _A. oryzae_ as an ideal platform for synthetic biology research on natural products [5; 62]. However, compared to _A. niger_, _A. oryzae_ remains less amenable to complex genetic manipulation. The active non-homologous end-joining (NHEI) pathway in _A. oryzae_ inherently results in low homologous recombination rates, making targeted gene knockouts or integrations challenging [168; 169]. Moreover, the rigid cell wall of _A. oryzae_ significantly impairs the efficiency of conventional transformation approaches, including electroporation and biolistics [166]. Consequently, genetic manipulation of _A. oryzae_ is predominantly dependent on polyethylene glycol (PEG)-mediated protoplast transformation, a laborious and time-consuming procedure that demands technical expertise [170]. In addition, despite the application of CRISPR/Cas9 technology in _A. oryzae_, its efficiency is constrained by multiple factors. The Cas9 protein exhibits low nuclear localization efficiency, and although partial improvement can be achieved through codon optimization and fusion with nuclear localization signals (NLS) as reported in previous studies [146], this remains a limiting factor. Furthermore, _A. oryzae_ displays intrinsic resistance to most antifungal antibiotics. This characteristic leads to a scarcity of viable dominant selectable markers, compelling researchers to predominantly rely on auxotrophic markers such as pyrG and argB for genetic selection procedures [166; 166]. Since 2015, the CRISPR/Cas system with its diverse engineering efficiencies has been progressively applied to genome editing in various filamentous fungi [171; 172; 173]; this system guides the Cas protein to target specific DNA sequences via the guide RNA (gRNA), enabling efficient and precise editing of the genome, including gene knockout, insertion, and point mutation, thereby contributing to the construction of a highly efficient filamentous fungal expression platform [174]. Although the CRISPR/Cas9 system has indeed enhanced the genome editing efficiency of _Aspergillus_ species, it still faces several challenges.