Genome-wide identification and characterization of TCP family genes in Brassica juncea var. tumida

Teosinte branched1/Cycloidea/proliferating cell factors (TCPs) are plant-specific transcription factors widely involved in leaf development, flowering, shoot branching, the circadian rhythm, hormone signaling, and stress responses. However, the TCP function in Brassica juncea var. tumida, the tumorous stem mustard, has not yet been reported. This study identified and characterized the entire TCP family members in B. juncea var. tumida.

We identified 62 BjTCP genes from the B. juncea var. tumida genome and analyzed their phylogenetic relationship, gene structure, protein motifs, chromosome location, and expression profile in different tissues.

Of the 62 BjTCP genes we identified in B. juncea var. tumida, containing 34 class I and 28 class II subfamily members, 61 were distributed on 18 chromosomes. Gene structure and conserved motif analysis showed that the same clade genes displayed a similar exon/intron gene structure and conserved motifs. Cis-acting element results showed that the same clade genes also had a similar cis-acting element; however, subtle differences implied a different regulatory pathway. The BjTCP18s members were low-expressed in Dayejie strains and the unswelling stage of Yonganxiaoye strains. Treatment with gibberellin (GA) and salicylic acid (SA) showed that GA and SA affect the expression levels of multiple TCP genes.

We performed the first genome-wide analysis of the TCP gene family of B. juncea var. tumida. Our results have provided valuable information for understanding the classification and functions of TCP genes in B. juncea var. tumida.