Identification of tubulin genes in amphidiploid representatives of the genus Brassica and their parent species

Aim. To identify α-, β-, and γ-tubulin genes in the six most economically important Brassica species, as well as to establish their phylogenetic classification and clarify their evolutionary history. Methods. Genome-wide identification of tubulin gene sequences, phylogeny reconstruction methods, and comparative genomics approaches, including synteny analysis. Results. 229 functional tubulin genes were identified in six representatives of the Brassica genus, including Brassica oleracea, Brassica rapa, Brassica nigra, Brassica napus, Brassica juncea, Brassica carinata. Phylogenetic analysis of the of identified tubulin genes showed that Brassica α-tubulins are divided into two phylogenetic Classes, and β-tubulins into 5 main groups, which are also observed in other Brassicaceae. Representatives of the Brassica γ-tubulin subfamily did not exhibit isotype diversity and were phylogenetically closer to TUG1. The synteny analysis confirmed the significant conservation of the tubulin gene set in the analyzed Brassica species, including those of allopolyploid origin. Conclusions. It has been shown that the tubulin gene family in Brassica representatives is characterized by significant conservation and an evolutionarily stable set of genes even in allopolyploid species, while the existing diversity of tubulin isotypes is shaped by earlier events of whole-genome rearrangements, which are common to most Brassicaceae.