Enzyme Inhibitors Cause Multiple Effects on Accumulation of Monoterpene Indole Alkaloids in Cambial Meristematic Cell Cultures.

BACKGROUND

Enzyme inhibitors have been used for the clarification of biosynthesis of natural products. cambial meristematic cell (CMC) culture has been established and proved to be a better monoterpeneindole alkaloid (MIA) producer than dedifferentiated cell (DDC) culture. However, little is known about the inter-relationship of the MIA-biosynthetic genes with respect to their transcription.

OBJECTIVE

To clarify effects of alteration of one gene transcription on transcript levels of another genes in MIA-biosynthetic pathway, and how the accumulation of MIAs in CMCs are influenced by the alteration of their biosynthetic gene transcript levels.

MATERIALS AND METHODS

3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR) inhibitor lovastatin and 1-deoxy-D-xylulose 5-phosphate synthase (DXS) inhibitor clomazone were fed to CMC cultures. The contents of MIAs were qualified by High Performance Liquid Chromatography and the transcript levels of the relevant genes were measured by qRT-PCR.

RESULTS

Lovastatin improved the accumulation of MIAs via increasing the transcription of their biosynthetic genes encoding DXS1, tryptonphan decarboxylase (TDC), loganic acid methyltransferase (LAMT), strictosidine synthase (STR), desacetoxyvindoline-4-hydroxylase (D4H) and ORCA3 (a jasmonate-responsive transcriptional regulator), whereas clomazone reduced the contents of MIAs and the mRNA levels of the corresponding genes.

CONCLUSION

The biosynthesis of MIAs in is is manipulated via a complex mechanism, the knowledge of which paves the way for rationally tuning metabolic flux to improve MIA production in CMCs.