# In Vitro Compatibility of Three Native Isolates of _Trichoderma_ with the Insecticide Chlorpyrifos
## 4 Discussion
Likewise, it is known that some microorganisms, including _Trichoderma_, are capable of using organophosphorus compounds metabolically to meet their energy requirements [53]. The radial growth of native _Trichoderma_ strains in media poisoned with different concentrations of chlorpyrifos can support the compatibility (Figure 2). However, the radial growth of three _Trichoderma_ is low when the chlorpyrifos concentration is 1400 mg/L. [PERSON] et al. [54] mentioned that the maximum inhibition of mycelial growth is related to increasing pesticide concentrations. On the other hand, chlorpyrifos compatibility can be explained by two mechanisms of tolerance. The first mentions that pesticides do not affect the viability of _Trichoderma_ due to structural changes in the target sites of pesticides. The second hypothesis refers to the degradation of chlorpyrifos [55]. Chlorpyrifos degradation has also been studied in bacteria such as _Bacillus_ sp. [53] and _Arthobacter_ sp. HM01 [56], etc. While in the fungi, species of _Trichoderma_ spp., _Fusarium_ spp., and _Cladosporium cladosporoides_ Hu-01 have been reported [57; 58]. However, concerning the genus _Trichoderma_, works, such as that of [PERSON] et al. [41], demonstrated in vitro that _T. asperellum_ could use chlorpyrifos at 250 mg/L as the only carbon source when it is placed in a medium minimum of salts without any other carbon source. Likewise, [PERSON] et al. [59] demonstrated that _T. harzianum_ and _T. virens_ had a better degrading effect on chlorpyrifos (25, 50, 75, and 100 mg/L) than endosulfan (organochlorine). This degradation could be attributed to the presence of the _opd_ gene (organophosphate degradation), which encodes the enzyme phosphothriesterase and can hydrolyze bonds such as P-O, P-F, P-NC, and P-S [51; 60; 61]. This gene has been identified in bacteria such as _Agrobacteriumrium radiobacter_ P230 [62], _Flavobacterium_ ATCC 27551, and _Pseudomonas diminuta_[60]. On the other hand, according to the Scopus database search,only _Trichoderma virens_ (GvT6) have been reported as carrying the _opd_ gene [63]. Based on this information, three native strains (TCA 3, 21, and 23) could have expressed the _opd_ gene to encode the enzyme capable of hydrolyzing the chlorpyrifos in the culture medium, which is evidenced in the growth (Figure 2b). On the other hand, it is known that in biodegradation, one of the primary products is TPC (3,5,6-trichloro-2-pyridinyl), which is resistant to microbial degradation due to its three chlorine groups, causing the degradation of chlorpyrifos, which may explain why on the fourth day of evaluation the radial growth of the three strains stopped compared to the control [33]. The antagonism of _Botrytis_ sp. by the three native strains (TCA 3, 21, and 23) of _Trichoderma_ is an important characteristic of the biological controller. This antagonistic capacity can be affected by the type of pesticide and its high concentration [64]. On the other hand, the inhibition of _Botrytis_ sp. growth is due to the capacity of hyperparasitism, antibiosis, and competition for nutrients and space by _Trichoderma_[29; 65]. [PERSON] et al. [65] mentioned that different _Trichoderma_ species show the potential to parasitize _Botrytis_ sp. both in the soil and the surface of plants. In the same way, cell wall degrading enzymes (\(\beta\)-1,3-glucanases) play a key role in the antagonism of _Botrytis_ sp [65]. Likewise, a ceratoplatanin protein (Ep1-1) produced for _T. harzianum_ can affect the expression of virulence genes of _Botrytis cinerea_[66]. Many studies have reported the participation of volatile organic compounds in the antibiosis of _B. cinerea_, such as 6-pentyl-\(\alpha\)-pyrone (6 PP), which has been identified as a metabolite of _T. atroviride_ and _T. asperellum_[67; 68; 69; 70]. A recent study has shown a new perspective of the antagonism of _Trichoderma afro-harzianum_ towards _Botrytis_ sp. at the transcriptional level, where it has been shown that this species can degrade oxalic acid (the virulence factor of _Botrytis_ sp.)