Distinct triterpene synthases in the laticifers of Euphorbia lathyris

Edith Forestier,Irini Pateraki,Albert Boronat,Sylvain Darnet,Carmen Romero-Segura,Myriam Preiss,Anne Berna,Hubert Schaller,Vincent Compagnon,Emilio Centeno,Thomas J Bach

doi:10.1038/s41598-019-40905-y

Abstract

Euphorbia lathyris was proposed about fifty years ago as a potential agroenergetic crop. The tremendous amounts of triterpenes present in its latex has driven investigations for transforming this particular biological fluid into an industrial hydrocarbon source. The huge accumulation of terpenes in the latex of many plant species represent a challenging question regarding cellular homeostasis. In fact, the enzymes, the mechanisms and the controllers that tune the amount of products accumulated in specialized compartments (to fulfill ecological roles) or deposited at important sites (as essential factors) are not known. Here, we have isolated oxidosqualene cyclases highly expressed in the latex of Euphorbia lathyris. This triterpene biosynthetic machinery is made of distinct paralogous enzymes responsible for the massive accumulation of steroidal and non-steroidal tetracyclic triterpenes. More than eighty years after the isolation of butyrospermol from shea butter (Heilbronn IM, Moffet GL, and Spring FS J. Chem. Soc. 1934, 1583), a butyrospermol synthase is characterized in this work using yeast and in folia heterologous expression assays.

Highlights

Euphorbia lathyris is a herbaceous plant native to the Mediterranean area and widespread in temperate regions
Polycyclic triterpenes are synthesized through the action of oxidosqualene cyclases (OSCs), called triterpene synthases, which convert the substrate 2,3-oxidoqualene into one or several products belonging to one or more groups of compounds having a defined triterpene backbone
The deprotonation and release of the final triterpene by an OSC active site is preceded by a series of rearrangements (1,2-shifts of hydride and methyl groups) that vary in number between the types of OSCs and define the triterpene skeletal diversity mentioned above

Summary

OPEN Distinct triterpene synthases in the laticifers of Euphorbia lathyris

Edith Forestier[1], Carmen Romero-Segura[2,3], Irini Pateraki 2,3, Emilio Centeno[2,3], Vincent Compagnon[1], Myriam Preiss[1], Anne Berna[1], Albert Boronat[2,3], Thomas J. We have isolated oxidosqualene cyclases highly expressed in the latex of Euphorbia lathyris This triterpene biosynthetic machinery is made of distinct paralogous enzymes responsible for the massive accumulation of steroidal and non-steroidal tetracyclic triterpenes. This illustrates the flexibility of triterpene synthases, which was described for several non-steroidal triterpene synthases from Arabidopsis thaliana able to generate an array of products when expressed in a yeast strain deficient in its endogenous lanosterol synthase[45] Some of these versatile catalysts like At1g78960/LUP2 from Arabidopsis thaliana[46] or PSM/ BAA97559 from Pisum sativum[47] were shown to produce small amounts of butyrospermol among a variety of tetracyclic and pentacyclic triterpenes[34]. Using yeast and in folia heterologous expression approaches we have shown that distinct triterpene synthases are responsible for the accumulation of tetracyclic triterpenes in the latex

Results and Discussion

Material and Methods

Author Contributions

Additional Information