Abstract:In this study, βtubulin genes of Salix matsudana Koidz. and S. matsudana var. tortusoa (Vilm.)Rehd. were cloned and identified. The sequence similarity, phylogeny, chromosomal localization and expression patterns were further analyzed. The result showed that each willow contained 20 βtubulin genes, and each gene shared more than 74.0% and 86.6% nucleotide and amino acid sequence similarity with one another in each willow species. There was over 85.8% amino acid sequence similarity of the βtubulin between the two willows. While the amino acid sequence similarity among Salix and other plants were larger than 81.5%. In the phylogenetic analysis, βtubulin proteins formed four classes, and it was presumed that Salix βtubulin gene families had undergone salicoid duplication and tandem duplication events combined with the study of chromosomal location of poplar βtubulin. However, TUB11 and TUB12 were possibly derived from segmental duplication or replicative transposition. The expression pattern analysis showed a tissue specificity of βtubulin genes in willows, and a section of duplicatedgene pairs showed different expression patterns in tested tissues. High degree of sequence similarity, evolutionary expansion and of members and expression pattern diversity of Salix βtubulin gene families might confer flexibility in cell division and growth which is of important significance to the development and growth habit of perennial woody plants.