Abstract:Floral fragrance and flower color are important ornamental traits of flower crops， which are key factors that determine flower quality and affect flower economic values. Therefore， cultivating new flower varieties with rich floral colors and pleasant flowers has long been the main breeding goal of horticulturists. As a representative of bulb cut flower varieties， Freesia hybrida has bright flowers and pleasant aroma. The key structural genes FhCHS1， FhDFR， Fh3GT， Fh5GT that control the synthesis of anthocyanin in Freesia and the key structural genes for terpene synthesis， FhTPS1 to FhTPS14， are highlighted， in addition to the fact that small amino acid differences between the sequences of the natural variants of the TPS genes in the wild species drive the enzyme's catalytic activity and product specificity， laying the groundwork for elucidating genetic differences among floral scents species. The synthesis of anthocyanin is also regulated by MYB-bHLH-WD40 in addition to structural genes， and the synthesis of floral scent is regulated by FhMYB21L2 and FhMYC2， in addition to the co-regulation of the expression of the flavonol synthase gene， FhFLS2， by FhMYB21L2. Finally， we look ahead to the potential application of the synthesis of anthocyanin and terpenoids.

Abstract:Cineraria （Pericallis hybrida） is an ornamental plant with multiple anthocyanin metabolic pathways and has varieties showing rare flower color phenotypes such as blue and bicolor. Elucidating the molecular mechanisms underlying the formation of these flower colors can provide valuable genetic resources in breeding of ornamental plants， particularly for the development of new blue flower varieties. Based on research experiences on cineraria， the authors summarized the research progress in the past 20 years on the unique anthocyanin structure， the regulatory pathways of anthocyanin biosynthesis， and the technical approaches used in flower color research. This review mainly introduces： （1） The pigment composition of different cineraria varieties and the polyacylation structure in blue varieties； （2） The genes involved in anthocyanin metabolism pathways such as polyacylation and acylation， and the function of transcription factors such as MYB and MADS-box in regulating flower color and spot formation； （3） The efficient genetic transformation system and viral-induced gene silencing system relevant to flower color research in cineraria， as well as progress in these areas. This article would like to provide references for future research on the flower color and molecular breeding of cineraria and other ornamental plants.

Abstract:The diverse array of variegated leaf plant species is characterized by a rich tapestry of chromatic patterns adorning their foliage. These distinctive markings not only confer aesthetic significance as a pivotal ornamental trait in plants， but also bear ecological and biological relevance such as facilitating reproductive processes， acting as a deterrent against natural adversaries， and adaptability to environmental fluctuations. This article provides a comprehensive review of recent advancements in the classification and formation of leaf variegation in ornamental plants. Based on distinctions in pigment accumulation and structural characteristics within leaf tissues， the microstructural categorization of variegation types is outlined， and the molecular mechanisms underlying leaf variegation formation are summarized. Alterations in structural genes and transcription factors that associate with pigment synthesis and metabolism， such as CHLH， DFR， CRD1， during leaf development， as well as mutations in genes that are related to organelle development and cell differentiation， including ZAT10 and VAR3， can directly or indirectly participate in leaf variegation formation by influencing differential pigment accumulation and altering leaf structure. While there have been numerous studies on the formation mechanisms of leaf variegation in ornamental plants， the genetic mechanisms underlying leaf variegation remain unclear. The reasons for differential gene expression in variegated leaf regions and the spatial distribution mechanisms of leaf variegation patterns are still areas requiring further investigation. Future research can involve the selection of model plants from variegated leaf species， building the pan-genome， integrating with multi-omics technologies such as pan-genomics， proteomics， and metabolomics. This approach might enable exploring the origin of leaf variegation， uncovering the adaptive responses of variegated leaf plants to their environments， and deciphering the evolutionary mechanisms underlying important plant traits and environmental adaptation.

Abstract:Lilium spp. originates in China and holds an important and special position in China's flower industry. Floral fragrance is a important label of its ornamental traits. Previous studies have shown that the main floral components of different fragrance types vary greatly. The differences between strongly scented lilies and lightly scented lilies are mainly concentrated in the differences of terpenoids， while the sampling period， location， environment， hormones and so on might lead to changes in floral components. At present， the research on the synthetic pathway of lily fragrance substances focuses on the terpene synthesis pathway， mostly on the functional study of terpene synthase and the analysis of the upstream regulatory network， while the functional analysis of the genes of the metabolic pathway of other floral fragrance components and the research on the molecular regulatory mechanism are still a lot of unanswered questions. Due to the lack of comprehensive and in-depth analysis of synthesis and regulatory mechanisms in floral fragrance， it is difficult to support precise modification of floral fragrance， ultimately resulting in a slow process of floral fragrance breeding. In-depth exploration and utilization of lily floral fragrance genes and improvement of related metabolic pathways and regulatory networks may be the following focus of lily floral fragrance. In this paper， we review and summarize the previous research on lily floral fragrance， and prospect the future research direction， in order to provide a reference for the subsequent research on the molecular regulatory mechanism of lily floral fragrance， and provide a reference for the directional cultivation of new lily varieties with pleasant fragrance.

Abstract:Flower fragrance is a significant ornamental feature of ornamental plants. As a worldwide woody flower， Rhododendron is famous because of rich colors and diverse patterns. Its floral fragrance is an important indicator of its quality. Studies have demonstrated that terpenoids， alcohols， esters， and ketones are the main components of rhododendron florets， and the release of these compounds is influenced by flower development， release site， and environmental conditions. Terpenoids are the most important floral components of Rhododendron， and terpenoid synthase gene is the main regulator in the metabolic pathway of floral substances. Through the genomics and metabolomics study， TPS family genes of Rhododendron ovatum were much more than those of other odorless Rhododendron plants. It is of great significance to study the floral composition and biosynthesis pathway in different species and varieties of Rhododendron for aromatic breeding and comprehensive utilization. This study reviewed the determination and analysis methods of floral composition of Rhododendron plants， the aroma components of Rhododendron species in subgenera， the synthesis and release law of aroma， and the biosynthetic pathway of aroma and key genes， which provided reference for the study of the genetic law of the synthesis and metabolism of main floral substances and breeding new varieties with obvious characteristic fragrance in Rhododendron.

Abstract:The NAC transcription factor family members play important roles in regulating plant growth and development. Many studies have been reported in model plants and crops， but the NAC transcription factors in ornamental plants remain systematically investigated. This review introduces the structure and classification of NAC transcription factors， and summarizes these researches in organ growth and development and stress response during 2004-2023， including five subjects： leaf margin morphogenesis， flower development， leaf senescence， petal senescence， and seed dormancy. Many studies were conducted in response to abiotic stress such as drought， salt， alkali， cold and heat， while the works to biotic stress were rare. Since most studies of the NAC transcription factors in ornamental plants are still preliminary and relying on bioinformatics analysis of family members and their transcriptional profile analysis， we proposed the future prospectives of NAC transcription factors in ornamental plants， including： （1） Identification of NAC transcription factors through taking advantage of the whole genome sequencing datasets； （2） Exploration of the mechanisms of NAC transcription factors in ornamental plants； （3） Investigation of the regulatory network in NAC transcription factors interplaying with other transcription factors； （4） Molecular breeding of ornamental plants based on genetic engineering or genome editing technologies.

Abstract:Glycosylation modification plays a crucial role in the growth and development of plants. The core enzyme that catalyzes the synthesis of glycosylation products is glycosyltransferase （GT）， which includes the UGT family members. The UGT family primarily utilizes uridine diphosphate （UDP） as the glycosyl donor. Plant glycosylation reactions play a crucial role in regulating the solubility， stability and bioactivity of various plant metabolites. Furthermore， they are closely associated with plant quality traits， the storage of volatile compounds and respond to abiotic and biotic stresses. This study reviews the structural and catalytic features， reaction types， and functional classifications of glycosyltransferases in ornamental plants. It summarizes current research progress on modifications of hormones， terpenoids， and flavonoids in ornamental plants via UDP-glycosyltransferases， eventually affecting flower color， leaf color， leaf morphology， plant adversity， and functional compounds. By reviewing and summarizing the relevant studies， this study will help to understand the role of glycosyltransferases in the metabolic regulation of ornamental plants. Furthermore， this will also lay a foundation for future innovation in ornamental plant germplasm improvement and the development of functional components.

Abstract:Lilium spp. are perennial bulbous herbs that include ornamental， edible， and medicinal lilies all with high economic value. Since Lily is identified with complex genetic background， high heterozygosity， incompatibility in distant hybridization， long cycle of traditional cross breeding as well as low breeding accuracy， it is difficult to breed for new varieties. These modern breeding techniques， including crossbreeding， mutation breeding， polyploidization breeding， protoplast fusion breeding， and genetic engineering， have been applied in lily. This article reviews and summarizes the methods for overcoming the barriers of distant hybridization in lily hybrid breeding， the treatments in mutation breeding， the technical approaches in polyploidization breeding and haploid breeding， the methods in protoplast isolation and fusion in protoplast fusion breeding， and the advances in lily genetic transformation and editing. In addition， several examples in lily breeding methods and techniques are listed， and the problems in techniques are proposed. The future development and application prospects in lily breeding technologies are discussed. This article aims to provide insights for future research on lily breeding technologies and their applications in breeding of lily varieties.

Abstract:As an important woody spice resource in the world and medicinal edible plant in China， oil-bearing Rose has a long history in cultivation and industrial application. Rose essential oil extracted from rose petals are widely used as supplementary in the chemical， pharmaceutical， and food processing fields. Its yield and quality rely on various factors， such as varieties， cultivation area， cultivation condition， extraction methods. The Rosa genus plant resources are abundant in China， but the deep processing technology of rose essential oil lagged behind. There is a need of summary on the characteristics of domestic oil-bearing roses and the current application status of rose essential oil. This study summarized the cultivation types and current situation of oil-bearing roses， the extraction technology of rose essential oils， relevant industry standards， chemical composition， and pharmacological effects. We also proposed recommendations on exploration and utilization of oil rose resources， establishment and optimization of extraction methodologies， improvement of relevant standards， expansion of production application field， and establishment of bioactivity research system. We aim to provide reference for the future development of China's rose industry and provide theoretical guidance for the innovative utilization of Rosa genus plant resources in China.

Abstract:In this study， two F₁ hybrid combinations via crossing white non-anemone-type chrysanthemum （male） with two red anemone-type chrysanthemums （female） were used to determine 11 inflorescence traits. Genetic analysis revealed that flower diameter， ray floret length， ray floret width and number of disc florets were accordant with the 0MG model without major gene control. Disc flower diameter， number of ray florets， disc floret length， disc floret width and the longest lobe length fitted to the 2MG-ADI model controlled by two major genes with add-demonstration-epistatic effect. Major genes for disc floret length and the longest lobe length had a heritability of approximately 70%， indicating high heritability. Correlation analysis revealed significant positive correlation among disc floret length， disc floret width and the longest lobe length. According to the color values （L*， a*， b*） of ray florets， F₁ populations were grouped into 5 different colors. The Shannon-Wiener index （H） of the ray florets of two hybrid combinations were 1.12 and 1.23， the colors varied widely. Additionally， we selected 30 anemone-type chrysanthemums with different colors from the parents and F₁ population and measured the flower color values （L*， a*， b*） of inside epidermis of disc florets and upper epidermis of ray florets. The results suggest a respectively significant positive correlation of L*， a* and b* values between the two. Through examining 10 anemone-type chrysanthemums with 5 different colors， the same pigment as well as similarity on cell morphology and size were observed between inside epidermis of disc florets and upper epidermis of ray florets， as well as outside epidermis of disc florets and lower epidermis of ray florets possess. The results provided a theoretical foundation for the genetic mapping of inflorescence traits and the cultivation of high-quality anemone-type chrysanthemum varieties.

Abstract:In this study， eight Rosa plants showing different flower colors were subjected for phenotypic observation using the CIELab color measurement system. The anthocyanins were qualified using the high-performance liquid chromatography-mass spectrometry （HPLC-MS/MS） techniques， and examined for the relationship with the flower colors. The results showed that eight anthocyanins components were first detected， including Cyanidin-3-（caffeoyl）-glucoside （Cy3CafG）， Cyanidin-3-O-galactopyranoside （Cy3Gal）， Peonidin-3-（caffeoyl）-glucoside （Pn3CafG）， Cyanidin-3-（cis-caffeoyl）-dimethyl-glucoside （Cy3（cisCaf）DmG）， Cyanidin-3-（trans-caffeoyl）-dimethyl-glucoside （Cy3（transCaf）DmG）， Cyanidin-3-dimethyl-glucoside （Cy3DmG）， Peonidin-3-（cis-caffeoyl）-rutinoside （Pn3（cisCaf）Ru）， Peonidin-3-（trans-caffeoyl）-rutinoside （Pn3（transCaf）Ru）. The anthocyanin glycosides include galactosylation， methylation modification， and caffeioylation modification， all of which have been reported for the first time in Rosa plants. The correlation analysis between anthocyanins and CIELab parameters showed that Cy3CafG and Cy3（cisCaf）DmG were positively correlated with petal redness （a^*）. Cy3Gal and Cy3（transCaf）DmG were significantly positively correlated with petal yellowness （b^*） and luminance （L^*）. This study provides a theoretical reference for the precise identification of anthocyanins in Rosa plants and the study of the mechanism of flower color formation， and provides a methodological basis for molecular breeding of Rosa plants.

Abstract:The bHLH transcription factor families is one of the largest families of transcription factors in plants. More and more plant bHLH transcription factor families have been identified presently. However， systematic analysis of the lily bHLH transcription factor family has not been reported.Based on the transcriptome data of Lilium， this study identified a total of 74 bHLH family members. All the bHLH proteins were hydrophilic， 93% of which were unstable proteins， and 61% were acidic proteins.Through the domain analysis， 25 conserved residues were accounted for ≥50% consistence， with R16， R17， L27， L49 and L59 being highly conserved. Sixty-four bHLH proteins were predicted to bind to DNA， including 58 E-box and 46 G-box bindings. Based on the phylogenetic analysis， lily bHLHs were assigned into 21 subfamilies， and they were annotated with functions on signal transduction， abiotic stress， plant growth and development， and substance synthesis. Three genes Unigene23213_All， CL1682.Contig2_All and CL8286.Contig2_All， which associated with ocimene and linalool biosynthesis， were cloned showing 97.30%-99.89% homology among varieties at each locus. The three genes were expressed in flowers， leaves and scales. The fundings of this research provided a valuable information in further study deciphering the functions of lily bHLH transcription factors.

Abstract:Terpene synthase （TPS） gene is a key regulator gene in the biosynthesis pathway of terpenoids， playing a crucial role in plant terpene metabolism. In this study， the floral fragrance components of lilac petals at different flower development stages （including bud stage， beginning stage， blooming stage and withering stage） were identified and analyzed on the basis of optimizing the floral conditions of headspace solid-phase microextraction （HS-SPME）. The key candidate genes of SoTPS2 and SoTPS3 were identified by combining genome and transcriptome data， and their isolation and preliminary functional investigation were carried out. The results showed that： （1） The optimal extraction condition was 30 °C for 40 min by analyzing the difference of types and release amount of volatile compounds under different extraction temperature and time. The total release of floral fragrance showed a trend of first increasing and then decreasing during the four flower development stages， and the peak （highest level） was observed at full flowering stage. Terpene compounds accounted for the highest proportion in total of floral compoents in the four periods， and the monoterpene ocimene was the highest. （2） The open reading frames （ORF） of SoTPS2 and SoTPS3 genes were 1731 bp and 1779 bp， respectively， encoding 576 and 592 amino acids. The deduced proteins have Terpene_Cyclase_Plant_C1 conservative structural domain， belonging to Isoprenoid_Biosyn_C1 superfamily. The highest transcripts of the two genes were detected in the petals via real-time PCR， and the increased expression was first detected followed by a decrease along with the flower development stages. The gene expressions positively correlated with the release of ocimene. （3） Through the transient overexpression of SoTPS2 and SoTPS3 genes in the petals of Antirrhinum majus， we observed 10.91 and 23.67-fold increased on the release of ocimene， respectively， compared with the unoverexpressed group. Collectively， the main components of floral fragrance in lilac petals are monoterpenes， and SoTPS2 and SoTPS3 as downstream regulating genes can contribute the synthesis of monoterpenes， especially ocimene.

Abstract:Non-specific lipid transfer proteins （nsLTPs） play a crucial role in the transport and secretion of lipids in plants. In this study， two type II nsLTPs were cloned， namely nsLTP2-1 and nsLTP2-2， and analyzes it with functional analysis from Lavandula angustifolia. The analysis of sequence characteristics revealed that the nsLTP2-1 and nsLTP2-2 genes putatively encode 119 and 117 amino acids， respectively， which exhibit conserved lipid transfer proteins （LTP） domains and 8 highly conserved cysteine residues. The phylogenetic analysis revealed that these genes are located in separate branches and share the closest genetic relationship with Perilla frutescens， a member of the Labiatae family. The analysis of gene expression showed that both genes exhibit high expression levels in flower buds， with minimal expression observed in leaves， stems， and petals. However， notable disparities in expression were observed in the calyx， with nsLTP2-1 and nsLTP2-2 demonstrating higher expression levels in mature and young calyxes， respectively. The expression of these genes in flower buds and leaves was found to be stimulated by heavy light， while their expression in flower buds was also induced by abscisic acid. Additionally， the expression of nsLTP2-1 and nsLTP2-2 in leaves was found be triggered by methyl jasmonate and ethylene， respectively. The subcellular localization of the yellow fluorescent protein （EYFP） fusion protein demonstrated that both nsLTPs were localized on the cell membrane and cell wall， indicating they may be related to the transport of secondary metabolites. Following the overexpression of nsLTP2-1 and nsLTP2-2， tobacco leaves were subjected to Nile red staining， after 485-543 nm excitation light excitation， the fluorescence of leaf glandular hair was more than that of wild type. This observation suggests a potential significance of the nsLTPs investigated in this study with regards to lipid synthesis and transport. These findings provide a fundamental basis for elucidating the role of lavender lipid transfer protein in lipid and terpenoid transportation.

Abstract:Fraxinus section Sciadanthus is known with three species： Fraxinus hupehensis from Central China， F. xanthoxyloides from Western Himalaya， and F. dimorpha from North Africa. These species exhibit an unusual biogeographic disjunction across Central China， Western Himalaya and North Africa， whereas their origin and evolutionary remain unclear. The phylogenetic relationships of this section was investigated using nuclear ribosomal ITS and chloroplast genes psbA-trnH， rpl32-trnL and matK. The Bayesian system tree constructed by ITS sequences supports the classification system proposed by Wallander， in which the species of Fraxinus were classified into six sections. F. hupehensis， F. xanthoxyloides and F. dimorpha were all resided to section Sciadanthus and formed a sister group with section Fraxinus. We found that F. xanthoxyloides may have originated from hybridization between F. dimorpha and a Eurasian species. The divergence time suggested that Fraxinus first differentiated at 42.05 Ma， section Sciadanthus initially diverged at 21.86 Ma， and F. hupehensis diverged at 11.87 Ma. The uplifts of the Tibetan Plateau in the Tertiary may be the driving force and main reason causing the disjunctive distribution in section Sciadanthus. F. hupehensis and F. xanthoxyloides are proposed to be relict plants conferred by this process.