Puzzling Out the Colchicine Biosynthetic Pathway

The giant genome of lily provides insights into the hybridization of cultivated lilies

Lilies are economically important monocots known for their ornamental flowers, bulbs, and large genomes. The absence of their genomic information has impeded evolutionary studies and genome-based breeding efforts. Here, we present reference genomes for Lilium sargentiae (lily, 35.66 Gb) and Gloriosa superba (flame lily, 5.09 Gb). The giant lily genome is shaped by recent long terminal repeat retroelements. Phylogenetic analysis reveals diverse, independent origins of lily cultivars. Gene families involved in sucrose and starch metabolism are significantly expanded in the lily genome. Key homologs of XTH22, SOC1, and AP1/FUL-like genes regulate the development, bud growth transition, and floral bud growth transition of lily bulbs. Colchicine biosynthetic gene clusters are identified in G. superba but are absent in L. sargentiae, highlighting independent colchicine evolution in Colchicaceae. These genomic insights enhance understanding of Liliales evolution, providing a foundation for future breeding and molecular research.

Salicylic acid modulates secondary metabolism and enhanced colchicine accumulation in long yellow daylily (Hemerocallis citrina)

Salicylic acid (SA) is an essential phytoregulator that is widely used to promote the synthesis of high-value nutraceuticals in plants. However, its application in daylily, an ornamental plant highly valued in traditional Chinese medicine, has not been reported. Herein, we investigated the exogenous SA-induced physiological, transcriptional and biochemical changes in long yellow daylily (LYD). We found that 2 mg/L foliar SA treatment significantly improved LYD plant growth and yield. Transcriptome sequencing and differentially expressed genes (DEGs) analysis revealed that the phenylpropanoid biosynthesis, isoquinoline alkaloid biosynthesis, sulfur metabolism, plant hormone signal transduction and tyrosine metabolism were significantly induced in SA-treated leaves. Many transcription factors and antioxidant system-related DEGs were induced under the SA treatment. Biochemical analyses showed that the leaf contents of soluble sugar, soluble protein (Cpr), ascorbic acid (AsA) and colchicine were significantly increased by 15.15% (from 30.16 ± 1.301 to 34.73 ± 0.861 mg/g), 19.54% (from 60.3 ± 2.227 to 72.08 ± 1.617 mg/g), 30.45% (from 190.1 ± 4.56 to 247.98 ± 11.652 μg/g) and 73.05% (from 3.08 ± 0.157 to 5.33 ± 0.462 μg/g), respectively, under the SA treatment. Furthermore, we identified 15 potential candidate genes for enhancing the growth, production and phytochemical content of LYD. Our results provide support for the bioaccumulation of colchicine in yellow daylily and valuable resources for biotechnological-assisted production of this important nutraceutical in Hemerocallis spp.

A New Insight into Toxicity of Colchicine Analogues by Molecular Docking Analysis Based on Intestinal Tight Junction Protein ZO-1

Colchicine (COL) is a well-known plant alkaloid long used for medical purposes due to the selective anti-inflammatory effect on acute gouty arthritis. It is also a kind of mitosis toxin with strong inhibitory effects of cell division and is therefore being applied to the treatment of various cancers. However, this product shows a variety of adverse effects that are significantly correlated with the dosage and have attracted much attention. For the first time, the present work obtained a new insight into the gastrointestinal toxicity of colchicine analogues by molecular docking analysis, which was based on the 3D structure of intestinal tight junction protein ZO-1 and the ligand library containing dozens of small-molecule compounds with the basic skeleton of COL and its metabolites. The binding energy and mode of protein–ligand interaction were investigated to better understand the structure–toxicity relationships of COL analogues and the mechanism of action as well. Cluster analysis clearly demonstrated the strong correlation between the binding energy and toxicity of ligand molecules. The interaction mode further revealed that the hydrogen bonding (via the C-7 amide or C-9 carbonyl group) and hydrophobic effect (at ring A or C) were both responsible for ZO-1-related gastrointestinal toxicity of COL analogues, while metabolic transformation via phase I and/or phase II reaction would significantly attenuate the gastrointestinal toxicity of colchicine, indicating an effective detoxication pathway through metabolism.