title: Mechanism of Action of the Benzimidazole Fungicide on Fusarium graminearum: Interfering with Polymerization of Monomeric Tubulin But Not Polymerized Microtubule.
abstract: Tubulins are the proposed target of clinically relevant anticancer drugs, anthelmintic, and fungicide. β2-tubulin of the plant pathogen Fusarium graminearum was considered as the target of benzimidazole compounds by homology modeling in our previous work. In this study, α1-, α2-, and β2-tubulin of F. graminearum were produced in Escherichia coli. Three benzimidazole compounds (carbendazim, benomyl, and thiabendazole) interacted with the recombinant β2-tubulin and reduced the maximum fluorescence intensity of 2 μM β2-tubulin 47, 50, and 25%, respectively, at saturation of compound-tubulin complexes. Furthermore, carbendazim significantly inhibited the polymerization of α1-/β2-tubulins and α2-/β2-tubulins 90.9 ± 0.4 and 93.5 ± 0.05%, respectively, in vitro. A similar result appeared with benomyl on the polymerization of α1-/β2-tubulins and α2-/β2-tubulins at 89.9 ± 0.1% and 92.6 ± 1.2% inhibition ratios, respectively. In addition, thiabendazole inhibited 81.6 ± 1% polymerization of α1-/β2-tubulins, whereas it had less effect on α2-/β2-tubulin polymerization, with 20.1 ± 1.9% inhibition ratio. However, the three compounds cannot destabilize the polymerized microtubule. To illuminate the issue, mapping the carbendazim binding sites and β/α subunit interface on β/α-tubulin complexes by homology modeling showed that the two domains were closed to each other. Understanding the nature of the interaction between benzimidazole compounds and F. graminearum tubulin is fundamental for the development of tubulin-specific anti-F. graminearum compounds.
authors.affiliation: All authors: College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, China; and second author: College of Forestry, Henan University of Science and Technology, Tianjing Rd No 70, 471003, Luoyang, People's Republic of China.
authors.forename: Yujun
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: All authors: College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, China; and second author: College of Forestry, Henan University of Science and Technology, Tianjing Rd No 70, 471003, Luoyang, People's Republic of China.
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Xu
authors.affiliation: All authors: College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, China; and second author: College of Forestry, Henan University of Science and Technology, Tianjing Rd No 70, 471003, Luoyang, People's Republic of China.
authors.forename: Yuanye
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: All authors: College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, China; and second author: College of Forestry, Henan University of Science and Technology, Tianjing Rd No 70, 471003, Luoyang, People's Republic of China.
authors.forename: Yabing
authors.initials: Y
authors.lastname: Duan
authors.affiliation: All authors: College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, China; and second author: College of Forestry, Henan University of Science and Technology, Tianjing Rd No 70, 471003, Luoyang, People's Republic of China.
authors.forename: Mingguo
authors.initials: M
authors.lastname: Zhou
mesh_terms: D001542:Benomyl / Q000494:pharmacology; D001562:Benzimidazoles / Q000494:pharmacology*; D002219:Carbamates / Q000494:pharmacology; D005656:Fungal Proteins / Q000378:metabolism; D005659:Fungicides, Industrial / Q000494:pharmacology*; D005670:Fusarium / Q000187:drug effects*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D008870:Microtubules / Q000502:physiology*; D008958:Models, Molecular; D058105:Polymerization / Q000187:drug effects; D011485:Protein Binding; D011487:Protein Conformation; D058849:Protein Refolding; D011994:Recombinant Proteins; D013827:Thiabendazole / Q000494:pharmacology; D014404:Tubulin / Q000502:physiology*
chemical_list: D001562:Benzimidazoles; D002219:Carbamates; D005656:Fungal Proteins; D005659:Fungicides, Industrial; D011994:Recombinant Proteins; D014404:Tubulin; C006698:carbendazim; D013827:Thiabendazole; D001542:Benomyl