In this study, we investigated the expression of seven MYB transcription factors (a total of 17 genes that included Dof1.1, IQD1-1, MYB28, MYB29, MYB34, MYB51, and MYB122 and their isoforms) involved in aliphatic and indolic glucosinolate (GSL) biosynthesis and analyzed the aliphatic and indolic GSL content in different organs of Chinese cabbage (Brassica rapassp. Pekinensis). MYB28 and MYB29 expression in the stem was dramatically different when compared with the levels in the other organs. MYB34, MYB122, MYB51, Dof1.1, and IQD1-1 showed very low transcript levels among different organs. HPLC analysis showed that the glucosinolates (GSLs) consisted of five aliphatic GSLs (progoitrin, sinigrin, glucoalyssin, gluconapin, and glucobrassicanapin) and four indolic GSLs (4-hydroxyglucobrassicin, glucobrassicin, 4-methoxygluco-brassicin, and neoglucobrassicin). Aliphatic GSLs exhibited 63.3% of the total GSLs content, followed by aromatic GSL (19.0%), indolic GSLs (10%), and unknown GSLs (7.7%) in different organs of Chinese cabbage. The total GSL content of different parts (ranked in descending order) was as follows: seed > flower > young leaves > stem > root > old leaves. The relationship between GSLs accumulation and expression of GSLs biosynthesis MYB TFs genes in different organs may be helpful to understand the mechanism of MYB TFs regulating GSL biosynthesis in Chinese cabbage.

Lycium chinense is well known in traditional Chinese herbal medicine for its medicinal value and composition, which have been widely studied for decades. However, further research on Lycium chinense is limited due to the lack of transcriptome and genomic information. The transcriptome of L. chinense was constructed by using an Illumina HiSeq 2000 sequencing platform. All 56,526 unigenes with an average length of 611 nt and an N50 equaling 848 nt were generated from 58,192,350 total raw reads after filtering and assembly. Unigenes were assembled by BLAST similarity searches and annotated with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) orthology identifiers. Using these transcriptome data, the majority of genes that are associated with phenylpropanoid biosynthesis in L. chinense were identified. In addition, phenylpropanoid biosynthesis-related gene expression and compound content in different organs were analyzed. We found that most phenylpropanoid genes were highly expressed in the red fruits, leaves, and flowers. An important phenylpropanoid, chlorogenic acid, was also found to be extremely abundant in leaves. Using Illumina sequencing technology, we have identified the function of novel homologous genes that regulate metabolic pathways in Lycium chinense.

Astragalus membranaceus is one of the most important traditional Korean and Chinese medicinal herbs because it contains triterpenoid saponins (astragaloside I, II, III, and IV), which have beneficial and pharmacological effects on health. In this study, we analyzed 10 mevalonate pathway genes that are involved in astragaloside biosynthesis using the Illumina/Solexa HiSeq2000 platform. We determined the expression levels of the 10 genes using quantitative real-time PCR, and analyzed the accumulation of astragalosides in different organs using high-performance liquid chromatography. Genes related to the mevalonate pathway were expressed in different levels in different organs. Almost all genes showed high transcript levels in the stem and leaf, with the lowest transcript levels being recorded in the root. In contrast, most astragalosides accumulated in the root. In particular, the astragaloside IV content was distributed in the following order: root (0.58 mg/g DW) > flower (0.27 mg/g DW) > stem (0.23 mg/g DW) > leaf (0.04 mg/g DW). In the root, astragaloside II exhibited the highest content (2.09 mg/g DW) compared to astragaloside I, III, and IV. Notably, gene expression did not follow the same pattern as astragaloside accumulation. We suggest carefully that astragalosides are synthesized in the leaves and stem and then translocated to the root. This study contributes towards improving our understanding of astragaloside biosynthesis in A. membranaceus.

Riboflavin (vitamin B2) is the precursor of flavin mononucleotide and flavin adenine dinucleotide—essential cofactors for a wide variety of enzymes involving in numerous metabolic processes. In this study, a partial-length cDNA encoding bifunctional GTP cyclohydrolase II/3,4-dihydroxy-2-butanone-4-phosphate synthase (LcRIBA), 2 full-length cDNAs encoding lumazine synthase (LcLS1 and LcLS2), and a full-length cDNA encoding riboflavin synthase (LcRS) were isolated from Lycium chinense, an important traditional medicinal plant. Sequence analyses showed that these genes exhibited high identities with their orthologous genes as well as having the same common features related to plant riboflavin biosynthetic genes. LcRIBA, like other plant RIBAs, contained a DHBPS region in its N terminus and a GCHII region in its C-terminal part. LcLSs and LcRS carried an N-terminal extension found in plant riboflavin biosynthetic genes unlike the orthologous microbial genes. Quantitative real-time polymerase chain reaction analysis showed that 4 riboflavin biosynthetic genes were constitutively expressed in all organs examined of L. chinense plants with the highest expression levels found in the leaves or red fruits. LcRIBA, which catalyzes 2 initial reactions in riboflavin biosynthetic pathway, was the highest transcript in the leaves, and hence, the richest content of riboflavin was detected in this organ. Our study might provide the basis for investigating the contribution of riboflavin in diverse biological activities of L. chinense and may facilitate the metabolic engineering of vitamin B2 in crop plants.