Lijun Liang

Liriope spicata is an important ornamental ground cover plant, with a fruit color that turns from green to black during the development and ripening stages. However, the material basis and regulatory mechanism of the color variation remains unclear. In this study, a total of 31 anthocyanins and 2 flavonols were identified from the skin of L. spicata fruit via integrative analysis on the metabolome and transcriptome of three developmental stages. The pigments of black/mature fruits are composed of five common anthocyanin compounds, of which Peonidin 3–O–rutinoside and Delphinidin 3–O–glucoside are the most differential metabolites for color conversion. Using dual-omics joint analysis, the mechanism of color formation was obtained as follows. The expression of structural genes including 4CL, F3H, F3′H, F3′5′H and UFGT were activated due to the upregulation of transcription factor genes MYB and bHLH. As a result, a large amount of precursor substances for the synthesis of flavonoids accumulated. After glycosylation, stable pigments were generated which promoted the accumulation of anthocyanins and the formation of black skin.

In this study, the metabolome and transcriptome profiles of ophiopogon japonicas fruit during five stages were analyzed to understand the mechanisms for the formation of color in the skin. Results showed that twenty eight types of flavonoids existed in the skin of the fruit, of which twenty five were anthocyanins and three were flavonols. Among the twenty five kinds of anthocyanins, Delphinidin 3-O-rutinoside, Delphinidin 3-O-glucoside, Petunidin 3-O-rutinoside, Cyanidin 3-O-galactoside and Delphinidin 3-O-galactoside were the major constitutes of the metabolites. Delphinidin 3-O-rutinoside and Delphinidin 3-O-glucoside were discovered to be responsible for the blue color of fruit due to their high correlation with genes in the connection network, especially for Delphinidin 3-O-rutinoside, which was the highest in the amount and accumulated rapidly to 67.6% in the last three stages. Analyzing the results of co-expression network between genes and anthocyanins by means of weighted gene co-expression network analysis (WGCNA), the biosynthesis genes of anthocyanin formed in the late stage were found to be F3’5’H, ANS and UFGT, and the regulatory gene was MYB, which determined the color change of O. japonicas fruit. The identification of key anthocyanins and dominant genes for blue skin of O. japonicas fruit has laid a theoretical basis for regulating the fruit pigmentation in ground cover plants.

S. miltiorrhiza is a well-known Chinese herb for the clinical treatment of cardiovascular and cerebrovascular diseases. Tanshinones and phenolic acids are the major secondary metabolites and significant pharmacological constituents of this plant. Kelch repeat F-box (KFB) proteins play important roles in plant secondary metabolism, but their regulation mechanism in S. miltiorrhiza has not been characterized. In this study, we systematically characterized the S. miltiorrhiza KFB gene family. In total, 31 SmKFB genes were isolated from S. miltiorrhiza. Phylogenetic analysis of those SmKFBs indicated that 31 SmKFBs can be divided into four groups. Thereinto, five SmKFBs (SmKFB1, 2, 3, 5, and 28) shared high homology with other plant KFBs which have been described to be regulators of secondary metabolism. The expression profile of SmKFBs under methyl jasmonate (MeJA) treatment deciphered that six SmKFBs (SmKFB1, 2, 5, 6, 11, and 15) were significantly downregulated, and two SmKFBs (SmKFB22 and 31) were significantly upregulated. Tissue-specific expression analysis found that four SmKFBs (SmKFB4, 11, 16, and 17) were expressed preferentially in aerial tissues, while two SmKFBs (SmKFB5, 25) were predominantly expressed in roots. Through a systematic analysis, we speculated that SmKFB1, 2, and 5 are potentially involved in phenolic acids biosynthesis.

Codonopsis taxa, as a traditional Chinese medicinal and edible plant, has found expanding domestic and foreign applications in recent decades. However, the poor management in germplasm resources market has inevitably caused an unnecessary hybrid of the provenances. In order to clarify the hybrid characteristics of germplasm resources in the main production area, the Codonopsis cultivars collected from the provinces Gansu, Shannxi, Shanxi, and Hubei of China were researched, using internal transcribed spacer (ITS) sequence technology. The confirmation of additive nucleotides based on the ITS sequencing of polymerase chain reaction (PCR) mixture was optimized and used to study the hybrid of Codonopsis cultivars. The results showed that when the ratio of PCR mixture increased up to 15 percent, the presence of a double peak in the sequencing electrophoresis map could be confirmed, suggesting the existence of additive nucleotides. According to the method above, 46 samples of Codonopsis cultivars collected during 2016 and 2017 were studied and compared with the samples collected from the year 2009 to 2010. All of the samples collected during 2016 and 2017 were hybridized and no genetic pure lines were found. In addition, the sites of variable base reduced greatly, concentrating at positions 122 and/or 226. These phenomena suggested that the genetic diversity of Codonopsis cultivars declined and the germplasm resources gradually converged. More attention should be paid to the reasonable exploitation and genetic breeding of Codonopsis taxa.