Insight into the B3Transcription Factor Superfamily and Expression Profiling of Genes in Axillary Buds after Topping in Tobacco(.).

Members of the plant-specific B3 transcription factor superfamily play important roles in various growth and developmental processes in plants. Even though there are many valuable studies on genes in other species, little is known about the B3 superfamily in tobacco. We identified 114 B3 proteins from tobacco using comparative genome analysis. These proteins were classified into four subfamilies based on their phylogenetic relationships, and include the ARF, RAV, LAV, and REM subfamilies. The chromosomal locations, gene structures, conserved protein motifs, and sub-cellular localizations of the tobacco B3 proteins were analyzed. The patterns of exon-intron numbers and arrangement and the protein structures of the tobacco B3 proteins were in general agreement with their phylogenetic relationships. The expression patterns of 114 genes revealed that many genes show tissue-specific expression. The expression levels of genes in axillary buds after topping showed that the genes are mainly up-regulated in response to topping, while the genes are down-regulated after topping.