Systematic characterization of CsbZIP transcription factors in Camelina sativa and functional analysis of CsbZIP-A12 mediating regulation of unsaturated fatty acid-enriched oil biosynthesis

Huiling Gao; Jinai Xue; Lixia Yuan; Yan Sun; Yanan Song; Chunhui Zhang; Runzhi Li; Xiaoyun Jia

doi:10.1016/j.ijbiomac.2024.132273

Systematic characterization of CsbZIP transcription factors in Camelina sativa and functional analysis of CsbZIP-A12 mediating regulation of unsaturated fatty acid-enriched oil biosynthesis

Int J Biol Macromol. 2024 May 9;270(Pt 1):132273. doi: 10.1016/j.ijbiomac.2024.132273. Online ahead of print.

Authors

Huiling Gao¹, Jinai Xue¹, Lixia Yuan², Yan Sun¹, Yanan Song¹, Chunhui Zhang¹, Runzhi Li³, Xiaoyun Jia⁴

Affiliations

¹ College of Agronomy/Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Shanxi Engineering Research Center for Genetics and Metabolism of Special Crops, Taigu, Shanxi, China.
² College of Biological Science and Technology, Jinzhong University, Jinzhong, Shanxi, China.
³ College of Agronomy/Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Shanxi Engineering Research Center for Genetics and Metabolism of Special Crops, Taigu, Shanxi, China. Electronic address: rli2001@126.com.
⁴ College of Agronomy/Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Shanxi Engineering Research Center for Genetics and Metabolism of Special Crops, Taigu, Shanxi, China. Electronic address: jiaxiaoyun@sxau.edu.cn.

PMID: 38734348
DOI: 10.1016/j.ijbiomac.2024.132273

Abstract

The basic leucine zipper (bZIP) transcription factors (TFs) function importantly in numerous life processes in plants. However, bZIP members and their biological roles remain unknown in Camelina sativa, a worldwide promising oil crop. Here, 220 CsbZIP proteins were identified in camelina and classified into thirteen groups. Two and 347 pairs of tandem and segmental duplication genes were detected to be underwent purification selection, with segmental duplication as the main driven-force of CsbZIP gene family expansion. Most CsbZIP genes displayed a tissue-specific expression pattern. Particularly, CsbZIP-A12 significantly positively correlated with many FA/oil biosynthesis-related genes, indicating CsbZIP-A12 may regulate lipid biosynthesis. Notably, yeast one-hybrid (Y1H), β-Glucuronidase (GUS), dual-luciferase (LUC) and EMSA assays evidenced that CsbZIP-A12 located in nucleus interacted with the promoters of CsSAD2-3 and CsFAD3-3 genes responsible for unsaturated fatty acid (UFA) synthesis, thus activating their transcriptions. Overexpression of CsbZIP-A12 led to an increase of total lipid by 3.275 % compared to the control, followed with oleic and α-linolenic acid levels enhanced by 3.4 % and 5.195 %, and up-regulated the expressions of CsSAD2-3, CsFAD3-3 and CsPDAT2-3 in camelina seeds. Furthermore, heterogeneous expression of CsbZIP-A12 significantly up-regulated the expressions of NtSAD2, NtFAD3 and NtPDAT genes in tobacco plants, thereby improving the levels of total lipids and UFAs in both leaves and seeds without negative effects on other agronomic traits. Together, our findings suggest that CsbZIP-A12 upregulates FA/oil biosynthesis by activating CsSAD2-3 and CsFAD3-3 as well as possible other related genes. These data lay a foundation for further functional analyses of CsbZIPs, providing new insights into the TF-based lipid metabolic engineering to increase vegetable oil yield and health-beneficial quality in oilseeds.

Keywords: Camelina sativa (L.) Crantz; Regulatory mechanism of lipid/oil biosynthesis; bZIP transcript factor.