## 3 Results
### Preliminary Phenotypic Analysis of Deletion and Overexpression Mutants  
To assess potential differences in growth among the deletion or overexpression strain (_Atps1_ and _Otps1_) and the wild-type, strains were cultivated on MEA, PDA, and CMA (Figure 4). Both mutants exhibited at a significantly slower rate than the wild-type on MEA media, while their growth rates on PDA and CMA did not show significant variations compared to the wild-type (Figure 4). Previous studies have suggested that a sluggish growth rate in an organism may be attributed to mutations in genetic factors [36]. This finding also validates the successful construction of engineered strains with _tps1_ deletion or overexpression, demonstrating their impact on biological growth. In addition, to verify whether the _tps1_ gene is a key gene affecting the synthesis of conidial pigments in _T. atroviride_, we also observed and analyzed the colony characteristics of the wild-type strain of _T. atroviride_ and its mutant strains cultured on PDA plates for 5 d (Figure 5A). The results showed that there was no significant difference between the _Atps1_ deletion strain and the _Otps1_ overexpression strain with denser colonies and more green pigment produced by the conidia, using the wild-type as a control (Figure 5A). The results suggest that the overexpression of _tps1_ may accelerate the synthesis of pigments in the conidia of _T. atroviride_. The molecular spore production of the colonies was determined under the same culture conditions, and it was found that there was no significant difference between the _Atps1_ mutant strain and the WT control strain (Figure 6), suggesting that the deletion of the _tps1_ gene did not affect conidial production, whereas the overexpression of the _tps1_ gene decreased conidial production. However, the role of the tps1 gene in promoting _T. atroviride_ HB20111 growth remains unknown. However, there is evidence that terpen may affect fungal growth [37]. Therefore, it is hypothesized that the _tps1_ gene may have the potential to regulate the composition and amount of terpen produced by _T. atroviride_ HB20111, thereby affecting mycelial growth. Figure 4: GC-MS chromatograms of wild-type 20111 (**a**), _tps1_-deleted mutant (**b**), and _tps1_-overexpressed mutant (**c**). Figure 5: Growth of terpenoid-synthase-deletion and -overexpression transformantsants. HB20111, \(\Delta\)_tps1_, and _Otps1_ were individually cultured on (**A**) potato dextrose agar (PDA), (**B**) malt extract agar (MEA), and (**C**) cornneal agar medium (CMA). The cultures were incubated for five days, followed by measurement. Figure 6: Conidia production of WT, \(\Delta\)_tps1_, and _Otps1_ strains. The value bars with ns are not significant, asterisk denotes statistically significant differences (**_p_ < 0.01). ### Preliminary Phenotypic Analysis of Deletion and Overexpression Mutants  
We also evaluated the effect of _tps1_ deletion or overexpression on the fungicidal potential of _T. atroviride_ against pathogenic fungi. The results showed that the wild-type progenitor strains and the \(\Delta\)_tps1_ and _Otps1_ mutants had inhibitory effects on all the tested pathogens (Figure 7, Table 1). Notably, \(\Delta\)_tps1_ exhibited higher inhibitory activity than the other two Trichoderma species on CM9 and FP, while _Otps1_ showed lower inhibitory activity. In terms of FOC inhibition, _Otps1_ demonstrated superior antifungal efficacy. These findings are in line with previous research on the antifungal properties of _Trichoderma viride_[38].