Reciprocal natural hybridization between Lycoris aurea and Lycoris radiata (Amaryllidaceae) identified by morphological, karyotypic and chloroplast genomic data.

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.

Multi-Omics Analysis Reveals Molecular Responses of Alkaloid Content Variations in Lycoris aurea Across Different Locations.

Lycoris aurea, celebrated for its visually striking flowers and significant medicinal value due to the presence of alkaloids such as lycorine and galanthamine, has intricate yet poorly understood regulatory mechanisms. This study provides a detailed examination of the transcriptomic, metabolomic and ecological dynamics of L. aurea, aiming to elucidate the underlying molecular mechanisms of alkaloid biosynthesis. Our comparative analysis across different ecological settings highlighted key genes involved in alkaloid biosynthesis, such as genes encoding aldehyde dehydrogenase and norbelladine 4'-O-methyltransferase, which were distinctively increased in the high alkaloids-producing group. We identified a total of 6871 differentially expressed genes and 915 metabolites involved in pathways like terpenoid backbone biosynthesis, phenylalanine, tyrosine and tryptophan biosynthesis. Protein interaction network analysis revealed significant upregulation of photosynthesis, photosystem and photosynthetic membrane pathways in the alkaloids-producing region. Furthermore, our research delineated the interactions among soil microbial communities, genes and plant and soil biochemical properties, noting that bacterial populations correlate with soil properties that favour the activation of metabolic pathways essential for alkaloid production. Collectively, this study advances our understanding of the genetic and metabolic alkaloid biosynthesis pathways in L. aurea, shedding light on the complex interactions that govern alkaloid production.

Lycorine inhibits the proliferation of neuroblastoma neuro-2a cells by inducing G2/M phase cell cycle arrest and apoptosis.

Lycorine, a benzylphenanthridine-type alkaloid extracted form Amarillidaceae genera, exhibits an efficacy against various types of cancer. Nonetheless, the impact of lycorine treatment on neuroblastoma has not yet been investigated. Here we utilized a combinatorial strategy to explore and to understand the effect of lycorine on neuroblastoma Neuro-2a cells. Our results indicated that lycorine inhibits the Neuro-2a cells proliferation by promoting cell apoptosis. In addition, wound healing assay revealed that lycorine inhibits the Neuo-2a cells migration. Comparative transcriptome analysis showed that lycorine has the potential to affect cycle pathway. Flow cytometry analysis confirmed that lycorine arrested the Neuro-2a cell cycle at G2/M phase. Furthermore, we detected that the protein expression of Cyclin A, Cyclin B1 and Cyclin E were decreased, whereas protein of p53, Tgfß3, Gadd45ß, Gadd45γ, p21 and p27 were increased after treatment with lycorine. Collectively, we propose that lycorine might be a valuable candidate therapeutic agent in combating neuroblastoma.

The influences of four types of soil on the growth, physiological and biochemical characteristics of Lycoris aurea (L' Her.) Herb.

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 (Pn), 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 Pn, biomass and lycorine content of L. aurea. Thus, humus soil can be used as medium suitable for artificial cultivation of L. aurea.

[Effects of Arg20 mutation on sodium channels activity of JZTX-V].

Jingzhaotoxin-V(JZTX-V) isolated from the venom of the spider Chilobrachys jingzhao is a novel potent inhibitor that acts on tetrodotoxin-resistant and tetrodotoxin-sensitive sodium channels in adult rat dorsal root ganglion(DRG) neurons. It is a 29-residue polypeptide toxin including three disulfide bridges. To investigate the structure-function relationship of the toxin, a mutant of JZTX-V in which Arg20 was substituted by Ala, was synthesized by solid-phase chemistry method with Fmoc-protected amino acids on the PS3 automated peptide synthesizer. The synthetic linear peptide was then purified by reversed-phase high performance liquid chromatography and oxidatively refolded under the optimal conditions. The refolded product was analyzed by matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry(MALDI-TOF MS) and electrophysiological experiments for its relative molecular weight and prohibitive activity of sodium channels respectively. The present findings show that the prohibitive effect of R20A-JZTX-V on TTX-S sodium channels in DRG neurons is almost the same as that of native JZTX-V, suggesting that Arg20 does not play any important role in inhibiting TTX-S sodium currents in DRG neurons. In contrast, the prohibitive level of R20A-JZTX-V on TTX-R sodium channels is reduced by at last 18.3 times, indicating that Arg20 is a key amino acid residue relative to the bioactivity of JZTX-V. It is presumed that the decrease in activity of R20A-JZTX-V is due to the changes of the property in the binding site in TTX-R sodium channels.

[Solid-phase chemical synthesis and oxidative refolding of Hainantoxin-III].

Hainantoxin-III (HNTX-III) was synthesized using solid-phase chemical method with Fmoc-protected amino acids. Reversed-phase high performance liquid chromatography (RP-HPLC) was used to monitor the oxidative refolding of linear HNTX-III. It is found that the best refolding yield for 0.1 g/L linear HNTX-III could be obtained in double-distilled aqueous solution at pH 7.5 containing 1.0 mol/L L-arginine, 1.0 mmol/L reduced glutathione (GSH), and 0.1 mmol/L oxidized glutathione (GSSG). The relative molecular mass of the refolded HNTX-III was determined to be 3 607.68 by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Only one peak was found in the RP-HPLC chromatogram for the mixed sample of native HNTX-III and refolded HNTX-III at ratio of 1 : 1, and the effect of refolded HNTX-III on neuromuscular transmission in isolated mouse phrenic nerve-diaphragm preparations was almost same as that of native HNTX-III. The results indicate that refolded HNTX-III had the same structure and biological activities as the native HNTX-III.

[Synthesis and oxidative refolding of an N-terminal truncate of jingzhaotoxin-V and characterization of its activities of sodium channels].

An N-terminal tyrosine residue truncate of Jingzhaotoxin-V (Y1-JZTX-V) was synthesized by solid-phase chemical methods using Fmoc-protected amino acids. Reversed-phase high performance liquid chromatography (RP-HPLC) and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to monitor the oxidative refolding of Y1-JZTX-V to find the optimal renaturation conditions of the synthetic linear peptide. When Y1-JZTX-V (0.05 mg/L) was dissolved in 0.1 mol/L Tris-HCl buffer containing 1 mmol/L GSH and 0.1 mmol/L GSSG at pH 7.50 and 4 degrees C, the best renaturation yield of the truncate toxin was obtained. Under the whole-cell patch-clamp mode, Y1-JZTX-V could inhibit tetrodotoxin-resistant (TTX-R) and tetrodotoxin-sensitive (TTX-S) sodium currents in adult rat dorsal root ganglion neurons with IC50 values of 160 nmol/L and 39.6 nmol/L, respectively. The inhibition potentiality of Y1-JZTX-V on TTX-S sodium currents was almost the same as the natural JZTX-V, while that on TTX-R sodium currents was obviously weakened. The IC50 value of Y1-JZTX-V on TTX-R sodium currents was 5.8 times as many as that of natural JZTX-V. Present findings indicated that the first tyrosine residue (Y1) in the N-terminal of JZTX-V was involved in the binding activities of JZTX-V to TTX-R sodium channels.