Let T n,β denote the set of trees on n vertices with fixed matching number β. In this paper, the tree with minimal Laplacian spectral radius over T kβ+1,β is determined, where k is an integer greater than one i.e. a conjecture posed by Feng et al. is proved (see [Feng LH, Li Q, Zhang XD. Minimizing the Laplacian spectral radius of trees with given matching number. Linear and Multilinear Algebra. 2007;55:199-207]).
Introduction
Platycodon grandiflorum root (PG), a popular traditional Chinese medicine, contains considerable chemical components with broad pharmacological activities. The complexity and diversity of the chemical components of PG from different origins contribute to its broad biological activities. The quality of southern PG is superior to that of northern PG, but the mechanisms underlying these differences remain unclear.
Objectives
In order to study variation in the differentially accumulated metabolites (DAMs), differentially expressed genes (DEGs), as well as their interactions and signalling pathways among PG from Anhui and Liaoning.
Methods
The metabolomes based on liquid chromatography–tandem mass spectrometry (LC–MS/MS) and the transcriptome based on high‐throughput sequencing technology were combined to comprehensively analyse PGn and PGb.
Results
A total of 6515 DEGs and 83 DAMs from the comparison of PG from Anhui and Liaoning were detected. Integrated analysis of metabolomic and transcriptomic data revealed that 215 DEGs and 57 DAMs were significantly enriched in 48 pathways according to KEGG pathway enrichment analysis, and 15 DEGs and 10 DAMs significantly enriched in the main pathway sesquiterpenoid and triterpenoid and phenylpropanoid biosynthesis might play a key role in complex response or regulatory processes.
Conclusion
Differences in PG from southern and northern China might thus stem from differences in environmental factors, such as precipitation, light duration, and humidity. The results of our study provide new insight into geographic variation in gene expression and metabolite accumulation and will enhance the utilisation of PG resources.
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