English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  As a traditional Chinese herb, safflower ( Carthamus tinctorius  L.) is valued for its florets to prevent cardiovascular and cerebrovascular diseases. Basing on previous chemical analysis, the main active compounds are flavonoids in its florets. Although flavonoid biosynthetic pathway has been well-documented in many model species, unique biosynthetic pathway remains to be explored in safflower. Of note, as an important class of transitional enzymes, chalcone isomerase (CHI) has not been characterized in safflower.    Results  According to our previous research, CHIs were identified in a safflower transcriptome library built by our lab. To characterize CHI in safflower, a CHI gene named  Ct CHI1 was identified. A multiple sequences alignment and phylogenetic tree demonstrate that  Ct CHI1 shares 92% amino acid identity and close relationship with CHI to  Saussurea medusa . Additionally, subcellular localization analysis indicated  Ct CHI1-GFP fusion protein was mainly in the cell nucleus. Further, we purified  Ct CHI1 protein from  E. coli  which can effectively catalyze isomerization of 2′,4′,4,6′-tetrahydroxychalcone into naringenin in vitro. Via genetic engineer technology, we successfully obtained transgenic tobacco and safflower lines. In transgenic tobacco, overexpression of  Ct CHI1 significantly inhibited main secondary metabolites accumulation, including quercetin (~ 79.63% for ovx-5 line) and anthocyanins (~ 64.55% for ovx-15 line). As shown in transgenic safflower, overexpression of  Ct CHI1 resulted in upstream genes  Ct PAL3 and  Ct C4H1 increasing dramatically (up to ~ 3.9fold) while  Ct 4CL3,  Ct F3H and  Ct DFR2 were inhibited. Also, comparing the whole metabolomics database by PCA and PLS-DA between transgenic and control group, 788 potential differential metabolites were marked and most of them displayed up-regulated trends. In parallel, some isolated secondary metabolites, such as hydroxysafflor yellow A (HSYA), rutin, kaempferol-3- O -β-rutinoside and dihydrokaempferol, accumulated in transgenic safflower plants.    Conclusions  In this study, we found that  Ct CHI1 is an active, functional, catalytic protein. Moreover,  Ct CHI1 can negatively and competitively regulate anthocyanins and quercetin pathway branches in tobacco. By contrast,  Ct CHI1 can positively regulate flavonol and chalcone metabolic flow in safflower. This research provides some clues to understand CHI’s differential biochemical functional characterization involving in flavonoid pathway. More molecular mechanisms of CHI remain to be explored in the near future.    Electronic supplementary material  The online version of this article (10.1186/s12870-019-1962-0) contains supplementary material, which is available to authorized users.

Integrating molecular characterization and metabolites profile revealed CtCHI1’s significant role in Carthamus tinctorius L.