Metabolome and whole transcriptome analyses reveal the molecular mechanisms underlying triterpenoid saponins biosynthesis in Sapindus mukorossi fruits

Published: 5 January 2022| Version 1 | DOI: 10.17632/kdbrsd6psp.1
Ting Xue


Sapindus mukorossi fruit has been widely used as a source of daily necessities, cosmetics, biomedicine, and biodiesel due to its high triterpenoid saponins (TSs) content. However, a systematic inventory of the regulatory mechanisms of TSs biosynthesis at different stages of fruit maturity is still lacking. Here, we identified 50 terpenoid metabolites by terpenoid-targeted metabolomics and found that mukurozioside and pyishiauoside were significantly upregulated in the mature fruit (S3) compared to the young fruit (S1) and mid-mature fruit (S2). A total of 1,669 differentially expressed (dif) lncRNAs, 13 dif-circRNAs, 219 dif-miRNAs, and 17,529 dif-mRNAs were identified by whole-transcriptome data. GO and KEGG enrichment analyses showed that these differentially expressed RNAs were significantly enriched in phenylpropanoid biosynthesis, metabolic process, and plant hormone signal transduction. Co-expression and ceRNA network analysis showed that lncRNA:MSTRG.18127.1 was positively correlated with gma-miR156k, SmHSF14, and SmAXY4 and that circRNAs and miRNAs can both regulate the expression of SmPGA4 and SmMFP2, affecting secondary metabolite biosynthesis. Correlation analysis between transcriptome and metabolite profiling showed that SmSE, Smβ-AS, SmCYP716A, SmUGT73, SmUGT94, SmTPS1, and SmTPS26 are key regulatory genes and that the upregulation of these genes may be beneficial to TSs biosynthesis. These findings can help elucidate the molecular mechanisms and regulatory networks of TSs biosynthesis in S. mukorossi and provide a biological basis for genomics-enabled improvements in molecular breeding.



Agricultural Plant