Enhancement of biomass and lipid productivity by overexpression of a bZIP transcription factor in Nannochloropsis salina

Abstract

TFs with basic leucine zipper (bZIP) domain have been identified as stress regulators and associated with regulating lipid metabolism. Normal condition and stress conditions were employed to confirm effects in NsbZIP1 overexpression strains. In our study, we overexpressed NsbZIP1 in N. salina CCMP1776 and confirmed by genomic PCR and western blotting. Transformants showed conspicuous increase under stress conditions. NsbZIP1 expression enhanced DCW and lipid content under stress conditions. NsbZIP1 transformants not only were able to maintain high electron transport rate, but also showed enhanced NPQ and Fv/Fm values. This results indicated that NsbZIP1 expression may be involved in the regulation and improvement of stress resistance as stress regulators. Also, NsbZIP1 activity accelerates TAG biosynthesis pathway by upregulating lipid-metabolizing genes specifically. We confirmed that NsbZIP1 activity play a widespread roles in mediating stress signaling as stress regulators and regulating growth and expression of gene related to lipid metabolism.