Medicinal Plant Research 2024, Vol.14, No.2, 71-84 http://hortherbpublisher.com/index.php/mpr 75 variations, analyzing different types of base modifications, and direct RNA sequencing (Ardui et al., 2018). It plays a crucial role in assembling complex genomes and identifying structural variations (Song et al., 2018). The combined use of bioinformatics tools and comparative genomics tools is employed to analyze gene expression patterns, identify differentially expressed genes, and elucidate the evolutionary mechanisms of traits and quality indicators (Zhang et al., 2010; Shulga et al., 2017; Won et al., 2017). 3.3 Key findings from genomic studies Genomic studies on Chrysanthemum morifolium have achieved significant breakthroughs, advancing our understanding of its economic and medicinal value. The construction of genetic linkage maps has obtained numerous quantitative trait loci (QTLs) associated with important traits such as flower diameter, ray floret layer number, and ray floret length, which are crucial for breeding programs (Zhang et al., 2011). Transcriptome analyses have revealed the gene regulatory networks involved in flavonoid biosynthesis and flower development, thereby comprehensively revealing the current life activity status of various cells or tissues (Liu et al., 2015; Yue et al., 2018). The whole genome sequencing of related species has provided in-depth insights into the origin and breeding history of cultivated Chrysanthemum morifolium. The research has also laid the foundation for future studies to decipher the molecular mechanisms underlying important horticultural traits (such as flower shape, flower color, plant form, and stress resistance) and for targeted breeding efforts (Won et al., 2017; Song et al., 2018; Hirakawa et al., 2019). Additionally, studies on the biosynthesis of bioactive components, such as flavonoids and caffeoylquinic acids, provides technical support for enhancing the economic and medicinal value of Chrysanthemum morifolium(Chen et al., 2020). By integrating these findings, researchers have been able to develop a comprehensive understanding of the current state of the genomic landscape of Chrysanthemum morifolium, paving the way for future studies aimed at improving its ornamental and medicinal properties. 4 Adaptive Evolution of Chrysanthemum morifolium 4.1 Genetic diversity and phylogenetic relationships Genetic diversity is an important genetic foundation for a species, playing a crucial role in its survival and reproduction. The higher the genetic diversity within a species population, the stronger its adaptability to harsh environments, making it easier for the species to reproduce and evolve. DNA molecular marker technologies, such as RFLP, RAPD, ISSR, and SCoT, are widely used methods for analyzing the genetic diversity of Chrysanthemum morifolium, offering advantages such as speed, efficiency, and accuracy. Chrysanthemum morifoliumexhibits rich genetic diversity, which is crucial for maintaining its adaptability and evolution. The use of various molecular markers such as SCoT, ISSR, and SSR, plays an important role in evaluating this diversity. Tang et al. (2018) used eight ISSR primers to analyze the genetic diversity and relationships of 40 medicinal plant samples from 40 genera of the Asteraceae family. Feng et al. (2016a) screened 32 SCoT primers and used them to analyze the genetic diversity of 32 individual plants from the “Xiaoyangju” population of Hangbaiju in Tongxiang, Zhejiang. This method can be effectively applied to the genetic diversity analysis and phylogenetic analysis of Chrysanthemum morifoliumgermplasm. Genetic diversity provides essential information for the rational use and conservation of Chrysanthemum morifolium. The extent of genetic diversity in Chrysanthemum morifoliumgermplasm is a product of long-term evolution and is a prerequisite for its survival, adaptation, and development. Higher genetic diversity or richer genetic variation implies a stronger ability of the organism to adapt to environmental changes. Molecular phylogenetic analysis is a fundamental method in bioinformatics, primarily used to study the evolutionary patterns, directions, rates, and the impacts of various molecular mechanisms on the structure and function of genes and genomes at the molecular level. Phylogenetic analysis can elucidate the evolutionary relationships between Chrysanthemum morifolium and its closely related species. Liu et al. (2012) used the chloroplast genome to construct a phylogenetic tree, clarifying its unique evolutionary history and speciation events. These studies indicate that Chrysanthemum morifoliumhas a close evolutionary relationship with related
RkJQdWJsaXNoZXIy MjQ4ODYzNA==