Based on the characteristics of Lycoris aurea (L. aurea) natural distribution and local soil types, we selected four representative types of soil, including humus soil, sandy soil, garden soil and yellow-brown soil, for conducting the cultivation experiments to investigate key soil factors influencing its growth and development and to select the soil types suitable for cultivating it. We found that there existed significant differences in the contents of mineral elements and the activities of soil enzymes (urease, phosphatase, sucrase and catalase) etc. Among which, the contents of organic matters, alkali-hydrolysable nitrogen, Ca and Mg as well as the activities of soil enzymes in humus soil were the highest ones. In yellow-brown soil, except for Fe, the values of all the other items were the lowest ones. Net photosynthetic rate (P_n), biomass and lycorine content in humus soil were all the highest ones, which were increased by 31.02, 69.39 and 55.79%, respectively, as compared to those of yellow-brown soil. Stepwise multiple regression analysis and path analysis indicated that alkali-hydrolysable nitrogen, and Ca etc. were key soil factors influencing P_n, biomass and lycorine content of L. aurea. Thus, humus soil can be used as medium suitable for artificial cultivation of L. aurea.

Background: Hybridization is considered as an important model of speciation, but the evolutionary process of natural hybridization is still poorly characterized in Lycoris. To reveal the phylogenetic relationship of two new putative natural hybrids in Lycoris, morphological, karyotypic and chloroplast genomic data of four Lycoris species were analyzed in this study. Results: Two putative natural hybrids (2n = 18 = 4 m + 5t + 6st + 3 T) possessed obvious heterozygosity features of L. radiata (2n = 22 = 10t + 12st) and L. aurea (2n = 14 = 8 m + 6 T) in morphology (e.g. leaf shape and flower color), karyotype (e.g. chromosome numbers, CPD/DAPI bands, 45S rDNA-FISH signals etc.) and chloroplast genomes. Among four Lycoris species, the composition and structure features of chloroplast genomes between L. radiata and the putative natural hybrid 1 (L. hunanensis), while L. aurea and the hybrid 2, were completely the same or highly similar, respectively. However, the features of the cp genomes between L. radiata and the hybrid 2, while L. aurea and the hybrid 1, including IR-LSC/SSC boundaries, SSRs, SNPs, and SNVs etc., were significantly different, respectively. Combining the karyotypes and cp genomes analysis, we affirmed that the natural hybrid 1 originated from the natural hybridization of L. radiata (♀) × L. aurea (♂), while the natural hybrid 2 from the hybridization of L. radiata (♂) × L. aurea (♀). Conclusion: The strong evidences for natural hybridization between L. radiata (2n = 22) and L. aurea (2n = 14) were found based on morphological, karyotypic and chloroplast genomic data. Their reciprocal hybridization gave rise to two new taxa (2n = 18) of Lycoris. This study revealed the origin of two new species of Lycoris and strongly supported the role of natural hybridization that facilitated lineage diversification in this genus.

Galanthamine, an alkaloid derived from the Amaryllidaceae family, serves as an acetylcholinesterase inhibitor. Due to its central cholinergic properties, this compound is being actively studied as a potential treatment for Alzheimer’s disease. However, the broader scope of its biological effects remains poorly understood. In this study, we explored the therapeutic potential of galanthamine in promoting neuronal differentiation and enhancing neurite outgrowth in neural stem and progenitor cells (NSPCs). Our detailed analysis demonstrated notable changes in neuronal morphology and complexity during maturation following galanthamine exposure. Notably, the compound significantly increased the proportion of neurons with multiple neurites, indicating its ability to stimulate neurite formation and foster the development of complex neuronal networks. Furthermore, galanthamine treatment led to a marked rise in the number of mature-appearing neurons, distinguished by elongated and intricate dendrites, highlighting its potential to enhance neural plasticity and repair mechanisms. Importantly, we also identified that galanthamine facilitates neuronal differentiation in NSPCs by up-regulating the insulin-like growth factor 2 signaling pathway. Collectively, these findings provide valuable insights into galanthamine’s role in Alzheimer’s disease and emphasize its promise as a therapeutic agent for this neurodegenerative disorder.

Lycoris aurea Herb is a plant renowned for its striking appearance and medicinal properties, particularly the production of alkaloids such as lycorine and galanthamine, which have therapeutic potential in treating diseases. Understanding the interaction between L. aurea and its rhizosphere microbiome is crucial, as the microbiome influences plant health, nutrient availability, and metabolite biosynthesis. This study investigated the interplay between rhizosphere microbiome and alkaloid levels in L. aurea using genetically identical plant samples collected from two ecologically distinct regions. The findings revealed that higher levels of lycorine and galanthamine correlated with specific soil physicochemical properties such as higher acid phosphatase activity and higher sodium and manganese levels. Additionally, quantitative Accu16STM and AccuITSTM sequencing demonstrated distinct bacterial and fungal diversities in the high alkaloids-producing group compared with the low alkaloids-producing group. Our study found that the abundance of four dominant bacterial phyla Acidobacteriota, Proteobacteria, Actinobacteriota, and Planctomycetota was higher in the low-alkaloid content group, whereas the dominant fungal phylum Ascomycota was more abundant in the high-alkaloid content group. Linear discriminant analysis revealed distinct variations in bacterial and fungal taxa, with the high-alkaloid content group containing ten bacterial indicators, such as Kitasatospora and Acidimicrobiaceae, and ten fungal taxa, including Boletales, Vandijckomycella and Sclerodermataceae. Functional annotations of microbial taxa revealed differences in metabolic functions such as chitinolysis and nitrate reduction in the high alkaloid groups, respectively. Moreover, Spearman correlation analysis underscored the relationships between microbial diversity and soil characteristics, particularly emphasizing the role of soil pH in influencing microbial populations. In conclusion, this research provides valuable insights into the environmental and rhizosphere microbial dynamics of L. aurea, offering implications for alkaloid biosynthesis and pharmacology.

Galanthamine, an alkaloid from the Amaryllidaceae family, serves as an inhibitor of acetylcholinesterase. Beause of its central cholinergic properties, galanthamine is currently being researched as a potential therapeutic agent for the treatment of Alzheimer's disease. Nevertheless, the full extent of its other biological activities is still unclear. Here, we investigated the therapeutic potential of galanthamine in inducing neuronal differentiation and enhancing neurite outgrowth in neural stem and progenitor cells (NSPCs). Our comprehensive analysis revealed significant alterations in neuronal morphology and complexity during neuronal maturation following galanthamine treatment. Specifically, galanthamine significantly increased the percentage of multiple-neurite neurons, suggesting its ability to stimulate neurite formation and promote the development of extensive neuronal networks. Additionally, treatment with galanthamine resulted in a considerable increase in the proportion of mature-appearing neurons, characterized by elongated and intricate dendrites, suggesting its potential in enhancing neural plasticity and repair. Importantly, we further confirmed that galanthamine promotes neuronal differentiation in NSPCs through up-regulation of the IGF2 signaling pathway. Altogether, these findings contribute significantly to our understanding of the effects of galanthamine on Alzheimer's disease and underscore its potential as a therapeutic agent for this neurodegenerative condition.

Lycoris aurea (L. aurea) can synthesize secondary metabolites, known as lycorine and galanthamine. Despite its pharmaceutical significance, the molecular mechanism underlying the accumulation of these medicinal components in L. aurea remains largely unexplored. Two populations of L. aurea (Hunan and Guangxi) with different contents of lycorine and galanthamine were selected for de novo RNA sequencing. A total of 337,746 unigenes were obtained, and 55,910 unigenes were differentially expressed between the two populations, consisting of 38,429 up-regulated and 17,481 down-regulated unigenes. Furthermore, expression pattern analysis showed that there were five differentially expressed genes involved in the biosynthesis of lycorine and galanthamine. Among them, tyrosine decarboxylase was significantly up-regulated, and it might be responsible for the differential accumulation of lycorine and galanthamine in different populations of L. aurea. Our findings provided new insights into the mechanism underlying the accumulation of lycorine and galanthamine, enriching the genetic resources for L. aurea breeding programs. Bangladesh J. Bot. 51(4): 767-777, 2022 (December)