OBJECTIVE: Citri Reticulatae Pericarpium (Chenpi, CRP) is one of the most used traditional Chinese medicines with great medicinal, dietary and collection values, among which the Citrus reticulata cv. 'Chachi' (Citrus reticulata cv. Chachiensis) from Guangdong Xinhui is the geoherb of CRP. Xinhui CRP in the market was often counterfeited with other varieties or origins, molecular identification method can effectively distinguish different CRP varieties, but it's still a difficult problem to identify the same CRP variety from different origin. It is necessary to discover a new molecular marker to ensure the safe and effective application of Xinhui CRP. METHODS: We selected one of the most studied transcription factor families in Citrus genus, MYB, to design the specific candidate primers on the conserved region. The primers with good band repeatability and high polymorphism were screened for PCR amplification of the test materials, and the genetic similarity coefficient among different families, genera, species, and origins were calculated. The cluster analysis was performed by unweighted pair group method using arithmetic average (UPGMA). RESULTS: A total of ten MYB primers were screened out to identify Xinhui CRP from plants from different family (Panax ginseng and Morus alba), genus (Clausena lansium and Zanthoxylum schinifolium), and species (Citrus reticulata, C. sinensis and C. maxima). Furthermore, two from the ten primers, M1 and M10, were found to distinguish Xinhui CRP from other origins. There were 169, 113, 133 and 134 polymorphic bands in the identification of different families, genera, species, and origins respectively, and the accordingly polymorphism ration were 79.88%, 76.87%, 79.20% and 82.84%. Moreover, M1 was discovered to be the best primer to identify Xinhui CRP from other seven origins, the cluster analysis results based on the genetic similarity coefficients were consistent with the geographical distribution. CONCLUSION This study established a novel molecular identification method according to MYB transcription factor, which can analyze the potential parental relationship of CRP germplasm, as well as identify the quality and origins of Xinhui CPR.

The 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR) is the last step key enzyme of the methylerythritol phosphate (MEP) pathway, synthesizing isopentenyl diphosphate and its allyl isomer dimethylallyl diphosphate, which is important for regulation of isoprenoid biosynthesis. Here the full-length cDNA of, designated(GenBank Accession No. KJ933412.1), was isolated fromfor the first time. TwHDR has an open reading frame (ORF) of 1386 bp encoding 461 amino acids. TwHDR exhibits high homology with HDRs of other plants, with an N-terminal conserved domain and three conserved cysteine residues.cDNA was cloned into an expression vector and transformed into anmutant. Since loss-of-functionmutant is lethal, the result showed that transformation ofcDNA rescued themutant. This complementation assay suggests that thecDNA encodes a functional HDR enzyme. The expression ofwas induced by methyl-jasmonate (MJ) insuspension cells. The expression ofreached the highest level after 1 h of MJ treatment. These results indicate that we have identified a functional TwHDR enzyme, which may play a pivotal role in the biosynthesis of diterpenoid triptolide in.

This study reported the obtainment of the full-length cDNA of Salvia miltiorrhiza hairy roots (Abbr: SmHDR, GenBank number: JX233817), via extracting Salvia miltiorrhiza hairy roots total RNA, designing specific primers according to the transcriptome data and using the RACE strategy, and then analyzed it with bioinformatics approaches. On this basis, using the real-time PCR to detect SmHDR gene expression after Ag+ induction, and testing tanshinones contents of corresponding samples by UPLC. SmHDR has 1 647 nucleotides, and an open reading frame (ORF) encoding a protein of 463 amino acid residues. The deduced protein has isoelectric point (pI) of 5.72 and a calculated molecular weight about 51.88 kD. In the secondary structure, the percentage of alpha helix, beta turn and random coil were 35.64%, 20.30% and 44.06%, respectively. Sequence alignment and phylogenetic analysis demonstrated that SmHDR had relative close relationship to the HDR of Picrorhiza kurrooa, similar to HDR from other species of plants. Real time PCR results indicated that elicitor of Ag+ stimulated the increase of mRNA expression of SmHDR. At the same time, results of ultra performance liquid chromatography (UPLC), used to examine the accumulation of diterpenoid tanshinones in hairy roots, showed that the contents of diterpenoid tanshinones in hairy roots of Salvia miltiorrhiza were increased dramatically at 12 h after treated with Ag+, and then decreased significantly. This result showed a positive correlation between the levels of mRNA expression and tanshinones accumulation in Salvia miltiorrhiza stimulated by Ag+. The content of tanshinones was gradually raised, and it had an obvious increase at 120 h. The bioinformatics analysis and gene expression indicated that SmHDR might be involved in tanshinones biosynthesis, which laid the foundation for further study of secondary metabolic regulation mechanism of tanshinones.