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Background Peucedanum praeruptorum Dunn is a perennial and one-time flowering medical plant whose early bolting significantly compromises both yield and quality. Previous research has shown that light conditions play a crucial role in regulating this early bolting phenomenon. In an attempt to elucidate the regulatory mechanism underlying light-mediated bolting in P. praeruptorum , we conducted shading experiments to systematically analyze the dynamic phenotypic variations, phytochemical composition changes, and transcriptomic profiles between early bolting and non-bolting plants under altered light conditions. Results Results showed that low light effectively inhibited the occurrence of early bolting, but it also significantly suppressed the growth of the plant. Additionally, shading significantly affected the accumulation of active components, the contents of bergapten, praeruptorin A, and praeruptorin E showed a positive correlation with light intensity, while praeruptorin B exhibited an inverse correlation. The 70% shading treatment was identified as the optimal condition, effectively mitigating early bolting while maintaining acceptable levels of plant growth and medicinal quality for P. praeruptorum cultivation. Transcriptome analysis of 96 samples revealed a progressive reduction in both total gene expression and the number of differentially expressed genes as shading intensity increased. Among these, we identified 757 differentially expressed genes significantly associated with early bolting regulation. Notably, 23 candidate genes, including PHYA , FT , bZIP , NAC , ABF , ERF1 , At1g72540 , CYCD3 , FKBP16 , DELLA , JAZ , MYC2 , SNRK2 , and AUX/IAA , were identified as potential regulators of early bolting in response to shading condition. In addition, 11 candidate genes regulating coumarin components were identified, including 4CL , CCR , CSE , CCoaOMT , and the change trends of their expression profiles were consistent with the contents of coumarin components. Conclusion These findings provide the first empirical evidence for the mechanisms underlying early bolting and quality formation in P. praeruptorum , and offer valuable insights into producing high-quality P. praeruptorum .

(S)-(+)-linalool is a non-cyclic oxygenated monoterpene which is very useful and widely used in the cosmetic industries, especially in the production of perfume and cologne. Thus, due to the high commercial value and high demand, the search for new plant sources rich in (S)-(+)-linalool in agricultural systems to develop the business of this compound is of great interest. This investigation focused on the diversity of phenotypic yield and phytochemical traits in Grammosciadium platycarpum populations collected from fourteen geographical regions in Iran. The goal was to identify the essential compounds and select the best populations for domestication, cultivation, and future breeding programs. The highest coefficient of variation was observed in the umbrellas per plant, plant length, internode length, leaf width, number of lateral branches, and essential oil yield (EOY). The shoot dry weight ranged from 27.15 to 41.56 (g/plant) and the fruit dry weight from 9.23 to 20.80 (g/plant) among different populations, which was observed in the QOR population. The fruit of the plant was employed to extract and determine the content plus constituents of the essential oil. The essential oil content (EOC) exhibited a extend from 0.81 to 1.63%. MAQ population indicated the maximum and OSH population revealed the minimum EOC. The highest EOY (0.228 g/plant) was observed in the MAQ population and the lowest (0.083 g/plant) was related to the MAR population. Based on GC-MS and GC analysis, 91.97 to 99.93% of the essential compounds of different populations of G. platycarpum were identified. According to the results, linalool (65.90-81.62%) and limonene (9.73–15.34%) were the main ingredients of the essential oil profile. Rutin, ferulic acid, and chlorogenic acid were detected as the major phenolic compounds using HPLC. The high diversity observed among different populations of G. platycarpum provides good potential for selecting the best populations and using them in domestication projects, cultivation, and breeding programs.

Complex coumarins (CCs) represent characteristic metabolites found in Apiaceae plants, possessing significant medical value. Their essential functional role is likely as protectants against pathogens and regulators responding to environmental stimuli. Utilizing genomes and transcriptomes from 34 Apiaceae plants, including our recently sequenced Peucedanum praeruptorum , we conduct comprehensive phylogenetic analyses to reconstruct the detailed evolutionary process of the CC biosynthetic pathway in Apiaceae. Our results show that three key enzymes – p -coumaroyl CoA 2’-hydroxylase (C2’H), C-prenyltransferase (C-PT), and cyclase – originated successively at different evolutionary nodes within Apiaceae through various means of gene duplications: ectopic and tandem duplications. Neofunctionalization endows these enzymes with novel functions necessary for CC biosynthesis, thus completing the pathway. Candidate genes are cloned for heterologous expression and subjected to in vitro enzymatic assays to test our hypothesis regarding the origins of the key enzymes, and the results precisely validate our evolutionary inferences. Among the three enzymes, C-PTs are likely the primary determinant of the structural diversity of CCs (linear/angular), due to divergent activities evolved to target different positions (C-6 or C-8) of umbelliferone. A key amino acid variation (Ala161/Thr161) is identified and proven to play a crucial role in the alteration of enzymatic activity, possibly resulting in distinct binding forms between enzymes and substrates, thereby leading to different products. In conclusion, this study provides a detailed trajectory for the establishment and evolution of the CC biosynthetic pathway in Apiaceae. It explains why only a portion, not all, of Apiaceae plants can produce CCs and reveals the mechanisms of CC structural diversity among different Apiaceae plants. This study explores the origin and evolution of complex coumarin (CC) biosynthetic pathway in Apiaceae. The results explain why CCs are only detected in limited Apiaceae species, and clarify the mechanism underlying the linear and angular configurations of Apiaceae CCs.

Background The genus Conioselinum Fisch. ex Hoffm. (Apiaceae) presents long-standing taxonomic challenges due to poorly resolved infrageneric relationships and significant morphological convergence with related genera such as Ligusticum s.l. Although integrating plastomes and nrDNA data has been effective in resolving complex phylogenies, a comprehensive phylogenetic framework and a critical reevaluation of key diagnostic traits for Conioselinum remain insufficient. Results Our nrDNA phylogeny established a robust framework supporting the monophyly of Conioselinum as nested within the Hymenidium clade, delineating three distinct subclades (A, B, and C). This phylogenetic framework is further corroborated by corresponding morphological traits. We reaffirmed that the terminal localization of vascular bundles in fruit ribs is a stable synapomorphy for Conioselinum , when integrated with a consistent suite of diagnostic markers—specifically deciduous basal leaves, linear bracteoles, and absent or obsolete calyx teeth—it effectively distinguishes the genus from closely related allies. Divergence time estimation traced a rapid radiation from the Late Miocene to the Pleistocene, coinciding with the Qinghai-Tibet Plateau uplift. Furthermore, selective pressure analyses identified positive or relaxed selection in six genes ( ycf1 , matK , rpoA , ycf2 , rps7 , and ccsA ), suggesting their role in adapting to alpine environmental stresses. Evident cytonuclear conflicts in some taxa underscore a complex history likely involving reticulate evolution. Conclusion This study highlights the utility of integrating phylogenomics with morphology to resolve complex taxonomies. Based on congruent evidence from both sources, we propose a revised circumscription for Conioselinum . Together, these molecular and morphological insights establish a solid foundation for future taxonomic revisions and enhance our understanding of adaptive diversification in Apiaceae.

Background Large proliferations of cytochrome P450 encoding genes resulting from gene duplications can be termed as ‘blooms’, providing genetic material for the genesis and evolution of biosynthetic pathways. Furanocoumarins are allelochemicals produced by many of the species in Apiaceaous plants belonging to the Apioideae subfamily of Apiaceae and have been described as being involved in the defence reaction against phytophageous insects. Results A bloom in the cytochromes P450 CYP71AJ subfamily has been identified, showing at least 2 clades and 6 subclades within the CYP71AJ subfamily. Two of the subclades were functionally assigned to the biosynthesis of furanocoumarins. Six substrate recognition sites (SRS1-6) important for the enzymatic conversion were investigated in the described cytochromes P450 and display significant variability within the CYP71AJ subfamily. Homology models underline a significant modification of the accession to the iron atom, which might explain the difference of the substrate specificity between the cytochromes P450 restricted to furanocoumarins as substrates and the orphan CYP71AJ. Conclusion Two subclades functionally assigned to the biosynthesis of furanocoumarins and four other subclades were identified and shown to be part of two distinct clades within the CYP71AJ subfamily. The subclades show significant variability within their substrate recognition sites between the clades, suggesting different biochemical functions and providing insights into the evolution of cytochrome P450 ‘blooms’ in response to environmental pressures.

Background Phylogenomic data rich in informative loci can significantly improve the support and resolution of phylogenetic tree and has been proven to be an effective tool for studying plant taxonomy and phylogeny. The genus Pachypleurum Ledeb., belonging to subfamily Apioideae (Apiaceae), comprises approximately seven species worldwide (six in China). Due to the long-standing taxonomic ambiguity of this genus, it is urgent need for investigation. Results In this current study, we obtained six Pachypleurum plastomes and performed comprehensively comparative analyses. The results showed that six Pachypleurum plastomes were conserved in genome structure, gene number, gene arrangement, codon bias and SSRs, but varied in genome size, GC content and SC/IR boundaries. These findings indicated that Pachypleurum plastomes showed both conservation and diversity. In addition, nine mutation hotspot regions ( mat K, rps 16, atp F, clp P, ndh E, trn H- psb A, psb K- psb I, acc D- psa I, ycf 4- cem A) were identified that can serve as potential DNA barcodes for species identification within the genus Pachypleurum . Phylogenetic analyses based on 79 commonly shared PCGs and ITS sequences robustly supported that the non-monophyly of Pachypleurum and six Pachypleurum members fell into two clades: Selineae and Acronema Clade. The phylogenetic results also showed that Chinese Pachypleurum taxa may be circumscribed to only one species ( P. alpinum ) and other five species previously placed in this genus may be transferred out this genus and the systematic position of them were also discussed. Finally, combined with plastome comparison, phylogenetic analyses and morphological characteristics, we discussed the morphological delimitation of Pachypleurum genus. Conclusions This study characterized six Pachypleurum plastomes and highlighted the power of plastome data to significantly improve the phylogenetic supports and resolutions. In conclusion, our study not only enriched the data on the plastomes of Pachypleurum , but also provided a framework for Pachypleurum and improved the taxonomic system of the Apiaceae family.

Furochromones are specific bioactive secondary metabolites of many Apiaceae plants. Their biosynthesis remains largely unexplored. In this work, we dissect the complete biosynthetic pathway of major furochromones in the medicinal plant Saposhnikovia divaricata by characterizing prenyltransferase, peucenin cyclase, methyltransferase, hydroxylase, and glycosyltransferases. De novo biosynthesis of prim- O -glucosylcimifugin and 5- O -methylvisamminoside is realized in Nicotiana benthamiana leaves. Through comparative genomic and transcriptomic analyses, we further find that proximal duplication and high expression of a pentaketide chromone synthase gene SdPCS , together with the presence of a lineage-specific peucenin cyclase gene SdPC , lead to the predominant accumulation of furochromones in the roots of S. divaricata among surveyed Apiaceae plants. This study paves the way for metabolic engineering production of furochromones, and sheds light into evolutionary mechanisms of furochromone biosynthesis among Apiaceae plants. The complete biosynthetic pathway of Prim- O -Glucosylcimifugin and 5- O -Methylvisamminoside in Saposhnikovia divaricata is resolved and their de novo biosynthesis is reconstructed in Nicotiana benthamiana leaves. The evolutionary mechanisms of furochromone biosynthesis among Apiaceae plants is further analyzed.

Peucedanum japonicum (PJ), a member of the Apiaceae family, is widely distributed and cultivated in East Asian countries for edible and functional foods. In this study, we compared the plastid genomes (plastomes) and 45S nuclear ribosomal DNA (45S nrDNA) simultaneously from 10 PJ collections. Plastome-based phylogenetic analysis showed that the PJ accessions were monophyletic within the genus Peucedanum . However, ten plastomes were classified into two different groups according to their length of inverted repeat (IR) block, the short-type (S-type) plastome group containing the 18.6 kbp of the original IR and the long-type (L-type) plastome group containing the 35.7 kbp of expanded IR by duplication of the 17.1 kbp of the large single copy region. A total of nine single nucleotide polymorphisms and eight insertions or deletions were identified among the five L-type plastomes, whereas large variations were identified among the five S-type plastomes. Calculation of synonymous substitution rates and divergence time estimation suggested that the 17 kbp IR expansion occurred recently. Molecular markers were developed and validated to classify the 55 PJ germplasm according to their plastome types. Our study would be useful for unraveling the dynamic evolution of plastomes in the Apiaceae family and for the molecular breeding of PJ.

Monitoring changes in the distribution and density of plant species often requires accurate and high-resolution baseline maps of those species. Detecting such change at the landscape scale is often problematic, particularly in remote areas. We examine a new technique to improve accuracy and objectivity in mapping vegetation, combining species distribution modelling and satellite image classification on a remote sub-Antarctic island. In this study, we combine spectral data from very high resolution WorldView-2 satellite imagery and terrain variables from a high resolution digital elevation model to improve mapping accuracy, in both pixel- and object-based classifications. Random forest classification was used to explore the effectiveness of these approaches on mapping the distribution of the critically endangered cushion plant Azorella macquariensis Orchard (Apiaceae) on sub-Antarctic Macquarie Island. Both pixel- and object-based classifications of the distribution of Azorella achieved very high overall validation accuracies (91.6-96.3%, Kappa = 0.849-0.924). Both two-class and three-class classifications were able to accurately and consistently identify the areas where Azorella was absent, indicating that these maps provide a suitable baseline for monitoring expected change in the distribution of the cushion plants. Detecting such change is critical given the threats this species is currently facing under altering environmental conditions. The method presented here has applications to monitoring a range of species, particularly in remote and isolated environments.

Based on field investigations, morphological and molecular systematic studies, a new species, (Apiaceae) from Hunan Province, China is described. Diagnostic morphological characters, full description and a detailed illustration are provided. The differences between and morphologically similar species are presented and discussed. Since no population assessment of this species in its whole distribution area is made, it is best to assign a conservation status of 'Data Deficient' (DD) for this species.