Molecular analysis and characterization of the Cochliobolus heterostrophus β-tubulin gene and its possible role in conferring resistance to benomyl

The Journal of General and Applied Microbiology

Mitsuya Tsuda¹  Seiji Ouchi²  Chihiro Tanaka¹  Kiminori Shimizu¹  Abdul Gafur² 

[1] Graduate School of Agriculture, Kyoto University;Faculty of Agriculture, Kinki University

关键词: benomyl;    benzimidazole;    beta-tubulin;    Bipolaris maydis;    fungicide resistance;   

DOI  :  10.2323/jgam.44.217

学科分类：微生物学和免疫学

来源: Applied Microbiology, Molecular and Cellulrar Biosciences Research Foundation

【 摘 要 】

Cochliobolus heterostrophus Tub1 described here is the first β-tubulin gene characterized from a naturally occurring benomyl-resistant ascomycete plant pathogen. The gene encodes a protein of 447 amino acids. The coding region of Tub1 is interrupted by three introns, of 116, 55, and 56 nt, situated after codons 4, 12, and 53, respectively. As a result of the preference for pyrimidines in the third position of the codons when a choice exists between purines and pyrimidines, codon usage in the Tub1 gene is biased. Tub1 shows high homology with β-tubulin genes of other ascomycete species. However, Tub1 is exceptional in having Tyr167, compared with Phe167, possessed by β-tubulin genes of other ascomycetes sequenced thus far. The Tyr167 residue has been associated with benomyl resistance in other organisms. In contrast, all other benomyl-implicated residues of Tub1 correspond to sensitivity. Based on these results, we suggest that benomyl resistance in the fungus probably is attributed to Tyr167.

【 授权许可】

Unknown