Untargeted LC-MS/MS-Based Metabolomic Profiling for the Edible and Medicinal Plant Salvia miltiorrhiza Under Different Levels of Cadmium Stress.

Salvia miltiorrhiza, a medicinal and edible plant, has been extensively applied to treat cardiovascular diseases and chronic hepatitis. Cadmium (Cd) affects the quality of S. miltiorrhiza, posing serious threats to human health. To reveal the metabolic mechanisms of S. miltiorrhiza's resistance to Cd stress, metabolite changes in S. miltiorrhiza roots treated with 0 (CK), 25 (T1), 50 (T2) and 100 (T3) mg kg-1 Cd by liquid chromatography coupled to mass spectrometry (LC-MS/MS) were investigated. A total of 305 metabolites were identified, and most of them were amino acids, organic acids and fatty acids, which contributed to the discrimination of CK from the Cd-treated groups. Among them, S. miltiorrhiza mainly upregulated o-tyrosine, chorismate and eudesmic acid in resistance to 25 mg kg-1 Cd; DL-tryptophan, L-aspartic acid, L-proline and chorismite in resistance to 50 mg kg-1 Cd; and L-proline, L-serine, L-histidine, eudesmic acid, and rosmarinic acid in resistance to 100 mg kg-1 Cd. It mainly downregulated unsaturated fatty acids (e.g., oleic acid, linoleic acid) in resistance to 25, 50, and 100 mg kg-1 Cd and upregulated saturated fatty acids (especially stearic acid) in resistance to 100 mg kg-1 Cd. Biosynthesis of unsaturated fatty acids, isoquinoline alkaloid, betalain, aminoacyl-tRNA, and tyrosine metabolism were the significantly enriched metabolic pathways and the most important pathways involved in the Cd resistance of S. miltiorrhiza. These data elucidated the crucial metabolic mechanisms involved in S. miltiorrhiza Cd resistance and the crucial metabolites that could be used to improve resistance to Cd stress in medicinal plant breeding.

A High-Density Genetic Map Enables Genome Synteny and QTL Mapping of Vegetative Growth and Leaf Traits in Gardenia.

The gardenia is a traditional medicinal horticultural plant in China, but its molecular genetic research has been largely hysteretic. Here, we constructed an F1 population with 200 true hybrid individuals. Using the genotyping-by-sequencing method, a high-density sex-average genetic map was generated that contained 4,249 SNPs with a total length of 1956.28 cM and an average genetic distance of 0.46 cM. We developed 17 SNP-based Kompetitive Allele-Specific PCR markers and found that 15 SNPs were successfully genotyped, of which 13 single-nucleotide polymorphism genotypings of 96 F1 individuals showed genotypes consistent with GBS-mined genotypes. A genomic collinearity analysis between gardenia and the Rubiaceae species Coffea arabica, Coffea canephora and Ophiorrhiza pumila showed the relativity strong conservation of LG11 with NC_039,919.1, HG974438.1 and Bliw01000011.1, respectively. Lastly, a quantitative trait loci analysis at three phenotyping time points (2019, 2020, and 2021) yielded 18 QTLs for growth-related traits and 31 QTLs for leaf-related traits, of which qBSBN7-1, qCD8 and qLNP2-1 could be repeatably detected. Five QTL regions (qCD8 and qSBD8, qBSBN7 and qSI7, qCD4-1 and qLLLS4, qLNP10 and qSLWS10-2, qSBD10 and qLLLS10) with potential pleiotropic effects were also observed. This study provides novel insight into molecular genetic research and could be helpful for further gene cloning and marker-assisted selection for early growth and development traits in the gardenia.

The complete chloroplast genome of Mitreola yangchunensis (Loganiaceae).

The complete chloroplast (cp) genome of Mitreola yangchunensis was sequenced and assembled for the first time. The genome is 154,665 bp in length, containing a large single-copy (LSC) region of 85,351 bp, a small single-copy region (SSC) of 18,218 bp and a pair of inverted repeats (IRs) of 25,548 bp. It contains 113 unique genes, including 79 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. The overall GC content is 37.9%, while the corresponding values of LSC, SSC, and IR regions are 35.9, 32.0, and 43.4%, respectively. Phylogenetic analyses using complete cp genomes showed that M. yangchunensis is most closely related to Mitrasacme pygmaea in Loganiaceae, and Gelsemiaceae and Loganiaceae form a single cluster with high support value.

The complete chloroplast genome of Stephania tetrandra (Menispermaceae).

The complete chloroplast genome of Stephania tetrandra was sequenced and assembled for the first time. The chloroplast genome is 159,974 bp in length, containing a large single-copy (LSC) region of 90,539 bp and a small single-copy region (SSC) of 20,735 bp, separated by a pair of inverted repeats (IRs) of 24,350 bp. The genome contains 113 unique genes, including 79 protein-coding genes (PCGs), 30 tRNA genes, and four rRNA genes. Among them, 15 genes have one intron each and three genes contain two introns. The overall GC content is 37.8%, while the corresponding values of LSC, SSC, and IR regions are 35.8, 32.4, and 43.7%, respectively. Phylogenetic analysis showed that S. tetrandra is more closely related to the clade of two species within Stephania, providing new insight into the evolution of Menispermaceae.