Cloning and Functional Expression of Cycloartenol Synthases from Mangrove SpeciesRhizophora stylosaGriff. andKandelia candel(L.) Druce

Abstract

To obtain cDNAs encoding oxidosqualene cyclase (OSC), we cloned two cDNAs, KcCAS and RsCAS, from roots of Kandelia candel (L.) Druce and leaves of Rhizophora stylosa Griff. by homology based PCR method respectively. The deduced amino acid sequences of both OSCs showed 82% homology to cycloartenol synthases from Lotus japonicus (OSC5) and Ricinus cummunis (RcCAS), suggesting that these are cycloartenol synthases of K. candel and R. stylosa. The genes obtained were expressed in a lanosterol synthase deficient Saccharomyces cerevisiae (ERG7) strain, GIL77. GC-MS analysis identified the accumulated reaction product in the yeast transformant to be cycloartenol, indicating that both KcCAS and RsCAS encode cycloartenol synthase.

Expression of terpenoid synthase mRNA and terpenoid content in salt stressed mangrove

“…Total RNA extraction and cDNA synthesis Total RNA from leaves and roots of K. candel and B. gymnorrhiza were extracted by using CTAB method as described in our previous report (Basyuni et al, 2007b) with minor modifications. Total RNA was dissolved into 20 mL of diethylpyrocarbonatetreated water (approximately 2-5 mg/mL).…”

“…The PCR primers were designed based on our previous and present study as shown in Table 1 (Basyuni et al, 2006(Basyuni et al, , 2007b.…”

“…In addition, two cDNAs for multifunctional terpenoid synthase (MS) and cyloartenol synthase, an enzyme responsible for the biosynthesis of plant sterol have also been cloned from K. candel (Basyuni et al, 2006(Basyuni et al, , 2007b. Figure 1 thus depicts the overall biosynthesis pathway of terpenoids in mangrove trees.…”

Protein modelling of triterpene synthase genes from mangrove plants using Phyre2 and Swiss-model

“…Figure 3 shows transmembrane (TM) helices in five triterpene synthases. BgbAS, BgLUS, RsM1, and KcMS had four TM helices (S1-S4), only RsM2 had five TM helices (S1-S5) both in the extracellular To gain more imminent into structural and functional roles of triterpenes, the well-defined and simple in vitro membrane models (liposomes) and in vitro study showed that triterpene, as well as phytosterol, was incorporated into the lipid bilayer of liposome [17], suggesting that triterpene was also a modulator of membrane permeability. Triterpene alcohols have been structurally distinguished from phytosterols, even though they share common biosynthetic pathway and hence the similar chemical structure.…”

“…Triterpene alcohols have been structurally distinguished from phytosterols, even though they share common biosynthetic pathway and hence the similar chemical structure. However, there has been no scientific basis to functionally identify these compounds as the structural membrane lipid [16][17]. Changes in the membrane lipid composition and properties represent an essential factor in the adaptation to high salt concentration [18].…”