AUTHOR=Yang Jiao , Tian Jingyi , Yang Yuhui , Zhu Yaru , Li Changfu , Zhang Yansheng 

TITLE=RNAi of Sterol Δ24-Isomerase Implicated Its Involvement in Physalin Biosynthesis in Physalis angulata L.

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.850711

DOI=10.3389/fpls.2022.850711

ISSN=1664-462X

ABSTRACT=<p><italic>Physalis angulata</italic> is a renowned traditional Chinese medicine for the treatment of various conditions. Physalin is the major type of bioactive constituents conferring medicinal properties of <italic>P. angulata</italic>. Despite the medicinal importance, the pathways leading to physalin are largely unknown. In this study, we employed a transcriptomic approach to identify a <italic>Pa24ISO</italic> gene from <italic>P. angulata</italic>. Through heterologous expression in yeast, Pa24ISO was revealed to catalyze an isomerization reaction in converting 24-methylenecholesterol to 24-methyldesmosterol. Real-time PCR analysis showed that the abundance of <italic>Pa24ISO</italic> transcripts correlated with the accumulation pattern of physalin B in different tissues of <italic>P. angulata</italic>. A direct role of Pa24ISO in channeling of 24-methylenecholesterol for physalin B biosynthesis was illustrated by suppressing the gene in <italic>P. angulata via</italic> the VIGS approach. Down-regulation of <italic>Pa24ISO</italic> led to reduced levels of 24-methyldesmosterol and physalin B, accompanied with an increase of campesterol content in <italic>P. angulata</italic>. The results supported that 24ISO is involved in physalin biosynthesis in plants.</p>