[Genome-wide identification of bZIP family genes and screening of candidate AarbZIPs involved in terpenoid biosynthesis in Artemisia argyi]

Artemisia argyi is an important medicinal and economic plant in China, with the effects of warming channels, dispersing cold, and relieving pain, inflammation, and allergy. The essential oil of this plant is rich in volatile terpenoids and widely used in moxi-bustion and healthcare products, with huge market potential. The bZIP transcription factors compose a large family in plants and are involved in the regulation of plant growth and development, stress response, and biosynthesis of secondary metabolites such as terpenoids. However, little is known about the bZIPs and their roles in A. argyi. In this study, the bZIP transcription factors in the genome of A. argyi were systematically identified, and their physicochemical properties, phylogenetic relationship, conserved motifs, and promoter-binding elements were analyzed. Candidate AarbZIP genes involved in terpenoid biosynthesis were screened out. The results showed that a total of 156 AarbZIP transcription factors were identified at the genomic level, with the lengths of 99-618 aa, the molecular weights of 11.7-67.8 kDa, and the theoretical isoelectric points of 4.56-10.16. According to the classification of bZIPs in Arabidopsis thaliana, the 156 AarbZIPs were classified into 12 subfamilies, and the members in the same subfamily had similar conserved motifs. The cis-acting elements of promoters showed that AarbZIP genes were possibly involved in light and hormonal pathways. Five AarbZIP genes that may be involved in the regulation of terpenoid biosynthesis were screened out by homologous alignment and phylogenetic analysis. The qRT-PCR results showed that the expression levels of the five AarbZIP genes varied significantly in different tissues of A. argyi. Specifically, AarbZIP29 and AarbZIP55 were highly expressed in the leaves and AarbZIP81, AarbZIP130, and AarbZIP150 in the flower buds. This study lays a foundation for the functional study of bZIP genes and their regulatory roles in the terpenoid biosynthesis in A. argyi.