Bioinformatics and expression analysis of NAC transcription factor genes in Scutellaria baicalensis

Abstract

Background: NAC, as a unique transcription factor to plants, plays important roles in multiple biological functions, such as regulation of plant growth and development, hormone levels, and responses to various kinds of stresses. However, there is a lack of research of NAC genes in Chinese herbs. Objective: The study aimed to evaluate the potential functions of NAC genes in Scutellaria baicalensis by bioinformatics and expression analysis, and provide evidence of the molecular regulation mechanism involved in flavonoid biosynthesis in S. baicalensis. Methods: The genes of NAC transcription factors in S. baicalensis were obtained from cDNA library and their functions were explored using bioinformatic methods. The NAC genes were screened from the cDNA library of S. baicalensis using BLAST comparison software. Then, the open reading frame (ORF) finder online tool was used to predict the full-length ORFs of NAC genes and their protein characteristics were explored by bioinformatic methods. The expression of NAC genes was then detected by quantitative polymerase chain reaction in different parts of S. baicalensis and different leaves treated by gibberellin GA3 treatment. Results: Six genes of NAC transcription factors were cloned, two of which had complete ORFs. NAC genes cloned in this study were mainly expressed in the flowers of S. baicalensis. The expression levels of NAC2, NAC3, NAC4, NAC5, NAC6 were increased firstly and then decreased gradually after 100 μM GA3 treatment. Meanwhile, some NACs and PAL2 in S. baicalensis showed strong correlation. Conclusion: This study suggested that NACs cloned in this study were mainly regulated the flavonoid biosynthesis in the flowers of S. baicalensis; NAC6 in S. baicalensis might be involved in the regulation of PAL2 transcription and affected the accumulation of flavonoids in the root of S. baicalensis. Our results provided a basis for further understanding the molecular regulation mechanism of flavonoid biosynthesis in S. baicalensis.