AUTHOR=Song Yadi , Zhou Jiawei , Zhang Yifeng , Zhao Yujun , Wang Xiujuan , Hu Tianyuan , Tong Yuru , Huang Luqi , Gao Wei 

TITLE=Overexpression of TwSQS, TwSE, and TwOSC Regulates Celastrol Accumulation in Cambial Meristematic Cells and Dedifferentiated Cells

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.926715

DOI=10.3389/fpls.2022.926715

ISSN=1664-462X

ABSTRACT=<p>Squalene synthase (SQS), squalene epoxidase (SE), and oxidosqualene cyclase (OSC) are encoding enzymes in downstream biosynthetic pathway of triterpenoid in plants, but the relationship between three genes and celastrol accumulation in <italic>Tripterygium wilfordii</italic> still remains unknown. Gene transformation system in plant can be used for studying gene function rapidly. However, there is no report on the application of cambial meristematic cells (CMCs) and dedifferentiated cells (DDCs) in genetic transformation systems. Our aim was to study the effects of individual overexpression of <italic>TwSQS</italic>, <italic>TwSE</italic>, and <italic>TwOSC</italic> on terpenoid accumulation and biosynthetic pathway related gene expression through CMCs and DDCs systems. Overexpression vectors of <italic>TwSQS</italic>, <italic>TwSE</italic>, and <italic>TwOSC</italic> were constructed by Gateway technology and transferred into CMCs and DDCs by gene gun. After overexpression, the content of celastrol was significantly increased in CMCs compared with the control group. However, there was no significant increment of celastrol in DDCs. Meanwhile, the relative expression levels of <italic>TwSQS</italic>, <italic>TwSE</italic>, <italic>TwOSC</italic>, and terpenoid biosynthetic pathway related genes were detected. The relative expression levels of <italic>TwSQS</italic>, <italic>TwSE</italic>, and <italic>TwOSC</italic> were increased compared with the control group in both CMCs and DDCs, while the pathway-related genes displayed different expression trends. Therefore, it was verified in <italic>T. wilfordii</italic> CMCs that overexpression of <italic>TwSQS</italic>, <italic>TwSE</italic>, and <italic>TwOSC</italic> increased celastrol accumulation and had different effects on the expression of related genes in terpenoid biosynthetic pathway, laying a foundation for further elucidating the downstream biosynthetic pathway of celastrol through <italic>T. wilfordii</italic> CMCs system.</p>