Characteristic analysis of BpbZIP family genes and BpbZIP26 significantly enhanced triterpenoid production in Betula platyphylla under S-nitrosothiol treatment

Abstract

Background Basic leucine zipper (bZIP) transcription factors are crucial in plant development, and response to environmental stress, etc. With the development of sequencing technology and bioinformatics analysis, the bZIP family genes has been screened and identified in many plant species, but bZIP family genes has not been systematically characterized and identified their function in Betula platyphylla. Methods B. platyphylla reference genome was used to characterize bZIP family genes. The physicochemical properties, chromosome distribution, gene structure, and syntenic relationships were analyzed by bioinformatics methods. The effect of BpbZIP26 on triterpenoid production was investigated using Agrobacterium-mediated transient transformation under N6022 treatment. Results 51 bZIP family genes were identified in B. platyphylla, and named BpbZIP1–BpbZIP51 sequentially according to their positions on chromosomes. All BpbZIP genes were unevenly distributed on 14 chromosomes, and divided into 13 subgroups according to the classification of Arabidopsis thaliana bZIP proteins. 12 duplication events were detected in the B. platyphylla genome, and 28 orthologs existed between B. platyphylla and A. thaliana, 83 orthologs existed between B. platyphylla and Glycine max, and 73 orthologs existed between B. platyphylla and Populus trichocarpa. N6022 treatment changed gene expression levels of most BpbZIPs in seedlings of B. platyphylla. Among of them, N6022 treatment significantly enhanced gene expression levels of BpbZIP26 in leaves, stems and roots of B. platyphylla. BpbZIP26 mediated triterpenoid production, and N6022 treatment further enhanced triterpenoid production in BpbZIP26 overexpression calli of B. platyphylla using Agrobacterium-mediated transient transformation. Conclusion This work highlights potential BpbZIP family genes responding to S-nitrosothiol and provides candidate genes for triterpenoid production in B. platyphylla. Graphical Abstract