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A Role in 15-Deacetylcalonectrin Acetylation in the Non-Enzymatic Cyclization of an Earlier Bicyclic Intermediate in Fusarium Trichothecene Biosynthesis.
- Source :
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International journal of molecular sciences [Int J Mol Sci] 2024 Apr 12; Vol. 25 (8). Date of Electronic Publication: 2024 Apr 12. - Publication Year :
- 2024
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Abstract
- The trichothecene biosynthesis in Fusarium begins with the cyclization of farnesyl pyrophosphate to trichodiene, followed by subsequent oxygenation to isotrichotriol. This initial bicyclic intermediate is further cyclized to isotrichodermol (ITDmol), a tricyclic precursor with a toxic trichothecene skeleton. Although the first cyclization and subsequent oxygenation are catalyzed by enzymes encoded by Tri5 and Tri4 , the second cyclization occurs non-enzymatically. Following ITDmol formation, the enzymes encoded by Tri101 , Tri11 , Tri3 , and Tri1 catalyze 3- O -acetylation, 15-hydroxylation, 15- O -acetylation, and A-ring oxygenation, respectively. In this study, we extensively analyzed the metabolites of the corresponding pathway-blocked mutants of Fusarium graminearum . The disruption of these Tri genes, except Tri3 , led to the accumulation of tricyclic trichothecenes as the main products: ITDmol due to Tri101 disruption; a mixture of isotrichodermin (ITD), 7-hydroxyisotrichodermin (7-HIT), and 8-hydroxyisotrichodermin (8-HIT) due to Tri11 disruption; and a mixture of calonectrin and 3-deacetylcalonectrin due to Tri1 disruption. However, the Δ Fgtri3 mutant accumulated substantial amounts of bicyclic metabolites, isotrichotriol and trichotriol, in addition to tricyclic 15-deacetylcalonectrin (15-deCAL). The Δ Fgtri5 Δ Fgtri3 double gene disruptant transformed ITD into 7-HIT, 8-HIT, and 15-deCAL. The deletion of FgTri3 and overexpression of Tri6 and Tri10 trichothecene regulatory genes did not result in the accumulation of 15-deCAL in the transgenic strain. Thus, the absence of Tri3p and/or the presence of a small amount of 15-deCAL adversely affected the non-enzymatic second cyclization and C-15 hydroxylation steps.<br />Competing Interests: The authors declare no conflicts of interest.
Details
- Language :
- English
- ISSN :
- 1422-0067
- Volume :
- 25
- Issue :
- 8
- Database :
- MEDLINE
- Journal :
- International journal of molecular sciences
- Publication Type :
- Academic Journal
- Accession number :
- 38673874
- Full Text :
- https://doi.org/10.3390/ijms25084288