Differences in amino acid composition of carrot α-tubulin potentially confer the resistance to dinitroaniline herbicides

Abstract

Aim. To reveal the features of amino acid composition of carrot α-tubulin isotypes that potentially determine natural tolerance to dinitroaniline herbicides. Methods. Literature and database search. Comparison of protein sequences and structures: multiple sequence alignment, phylogenetic profiling, protein and ligand structure modeling, etc. Results. Genomic and proteomic analysis of Daucus carota has revealed at least eight unique isotypes of α-tubulin that differ in amino acid sequences and gene loci. Remarkable differences in amino acid composition of the dinitroanilinebinding-like (DBL) region of analyzed α-tubulin have been revealed, which may be the reason of its natural resistance to these compounds. Сonclusions. Differences in amino acids at positions of canonical mutations – Cys4 (TBA1, 2, 3, 6, 7 and 8), Thr53 (TBA6), Ile202 (TBA1 and 7) and Met202 (TBA5), as well as previously undescribed non-canonical substitutions – Ile4 (TBA4 and 5), Cys52 (TBA6), Ser201 (TBA1, 2, 3 and 8) and Val194 (TBA4 and 5), were noted as potentially associated with natural tolerance of the carrot to dinitroaniline herbicides.