Cold Resistance of Euonymus japonicus Beihaidao Leaves and Its Chloroplast Genome Structure and Comparison with Celastraceae Species

Abstract

Euonymus japonicus Beihaidao is one of the most economically important ornamental species of the Euonymus genus. There are approximately 97 genera and 1194 species of plants worldwide in this family (Celastraceae). Using E. japonicus Beihaidao, we conducted a preliminary study of the cold resistance of this species, evaluated its performance during winter, assembled and annotated its chloroplast genome, and performed a series of analyses to investigate its gene structure GC content, sequence alignment, and nucleic acid diversity. Our objectives were to understand the evolutionary relationships of the genus and to identify positive selection genes that may be related to adaptations to environmental change. The results indicated that E. japonicus Beihaidao leaves have certain cold resistance and can maintain their viability during wintering. Moreover, the chloroplast genome of E. japonicus Beihaidao is a typical double-linked ring tetrad structure, which is similar to that of the other four Euonymus species, E. hamiltonianus, E. phellomanus, E. schensianus, and E. szechuanensis, in terms of gene structure, gene species, gene number, and GC content. Compared to other Celastraceae species, the variation in the chloroplast genome sequence was lower, and the gene structure was more stable. The phylogenetic relationships of 37 species inferred that members of the Euonymus genus do not form a clade and that E. japonicus Beihaidao is closely related to E. japonicus and E. fortunei. A total of 11 functional positive selected genes were identified, which may have played an important role in the process of Celastraceae species adapting to environmental changes. Our study provides important genetic information to support further investigations into the phylogenetic development and adaptive evolution of Celastraceae species.

Comparative Analysis of Chloroplast Pan-Genomes and Transcriptomics Reveals Cold Adaptation in Medicago sativa

“…Research has shown that low temperatures can inhibit the biogenesis and development of chloroplasts during the early greening stage of rice (Oryza sativa L.) seedlings [25]. Atpl and atpE play an important role in the adaptation of species to environmental changes within the Celastraceae family, affecting electron transfer and energy synthesis processes [26]. Tobacco lacking the chloroplast gene petL displays impaired photosynthesis and bleached leaves in cold conditions [27].…”

Diversity of Colletotrichum species associated with anthracnose on Euonymus japonicus and their sensitivity to fungicides

“…The water retention capacity of E. japonicus leaves surpasses that of Ligustrum vicaryi among broad-leaved shrub species, thereby enhancing both the aesthetic and functional aspects of landscape through improved soil water storage ( Yin et al., 2008 ). In Beijing, E. japonicus is extensively cultivated as a shrub due to its robust resistance to the dry and cold climatic conditions prevalent in the region, effectively reducing particulate matter during winter ( Cai et al., 2022 ). However, E. japonicus is highly susceptible to fungal diseases such as powdery mildew and anthracnose ( Yao et al., 2018 ; Lin et al., 2023 ).…”