Multi-algorithm cooperation in PnbHLH genes under Nitrogen stress

Panax notoginseng (Burkill) F. H. Chen ex C. H. increasingly entered into people's daily life, but its quality has been greatly affected in recent years. Panax notoginseng is one of the representatives of the ginseng plant of Araliaceae, which is an important and precious local medicinal material in China. Basic helix–loop–helix transcription factors play an irreplaceable position in the life of plants and have obvious reactions to stresses. However, studies on the growth and resistance of P. notoginseng basic helix–loop–helixs under Nitrogen stress have not been extensively explored. In this paper, the 126 P. notoginseng basic helix–loop–helixs were analyzed by virtue of their chromosomal localization. The 98 genes were located on 12 chromosomes irregularly. In addition, collinearity events were mainly composed of fragment repetitions. Through phylogenetic analysis, the proteins were divided into 22 subgroups. The same set of genes had semblable motifs, gene structures, and cis-acting elements. Tissue specificity revealed expression levels of P. notoginseng basic helix–loop–helixs in roots, leaves, and flowers. Finally, some genes in the roots of P. notoginseng were differentially expressed under Nitrogen stress, especially P. notoginseng basic helix–loop–helix49 was significantly up-regulated. It can be used as a candidate gene which can resist Nitrogen stress. This study will not only lay the foundation to explore the functions of P. notoginseng basic helix–loop–helixs, but also be helpful for the further research of P. notoginseng.