Molecular cloning and transgenic characterization of the genes encoding chalcone synthase and chalcone isomerase from the Tibetan herbal plant Mirabilis himalaica

Abstract

Mirabilis himalaica is an endangered medicinal plant species in the Tibetan Plateau. The two genes respectively encoding chalcone synthase (MhCHS) and chalcone isomerase (MhCHI) were isolated and characterized from M. himalaica. The sequence analysis revealed that the two genes were similar with their corresponding homologous genes in other plants. The tissue profiles showed that both MhCHS and MhCHI had higher expression levels in roots than in stems and leaves. Transgenic hairy root cultures respectively with overexpressing MhCHS and MhCHI were established. The genomic PCR detection confirmed the authority of transgenic hairy root lines, in which either MhCHS or MhCHI expression levels were much higher than that in non-transgenic hairy root line. Finally, the HPLC detection results demonstrated that the rotenoid contents in MhCHS/MhCHI-transformed hairy root lines were enhanced. This study provided two candidate genes that could be used to genetic engineering rotenoid biosynthesis in M. himalaica and an alternative method to produce rotenoid using transgenic hairy root cultures.

Integrated analysis of transcriptomic and metabolomic data reveals critical metabolic pathways involved in rotenoid biosynthesis in the medicinal plant Mirabilis himalaica

“…Therefore, researchers should pay increased attention to the biosynthesis of rotenoid in M. himalaica . In M. himalaica , rotenoid is primarily derived from the isoflavonoid biosynthesis pathway (Lan et al 2016 ). However, the detailed steps of rotenoid biosynthesis remain largely unknown.…”

“…5 ). CHS and CHI play important roles during the upstream catalysis of rotenoid, but some critical nodes remain largely unknown (Lan et al 2016 ). In the present study, the combined analysis of the transcriptomic and metabolic profiles of M. himalaica indicated that some metabolites downstream of naringenin chalcone metabolism were produced in types and amounts more than those involved in rotenoid biosynthesis from isoliquiritigenin.…”

“…Moreover, the expression trend of CHI (TR133939) was consistent with the accumulation pattern of rotenoid. Therefore, the CHI genes play an important role in the molecular synthesis of rotenoid (Lan et al 2016 ).…”

“…Moreover, insufficient data on the critical metabolites in M. himalaica has severely hindered the screening of its active medicinal compounds. On the other hand, many studies have shown that rotenoid, which exhibits remarkable anticancer effects, is among the active medicinal compounds in M. himalaica (Fan 2012 ; Linghu et al 2014 ; Lan et al 2016 ). However, the synthesis mechanism of rotenoid and its related metabolites in M. himalaica remains unclear because of a lack of available genetic information, especially at the molecular level.…”

Integrated Analysis of Transcriptomic and Proteomics Data Reveals the Induction Effects of Rotenoid Biosynthesis of Mirabilis himalaica Caused by UV-B Radiation

“…It is possible that the metabolic activities of M. himalaica are significantly enhanced under the UV-B radiation, and M. himalaica adapts to UV-B radiation by increasing the ultraviolet-absorbing substance. Rotenoid, an important medicinal active ingredient in M. himalaica , is one of the downstream products of flavonoid metabolism [ 58 , 59 ]. Previous studies on rotenoid have been focused extensively on its anti-cancer activity and the treatment of leukemia [ 60 , 61 , 62 ].…”