Search Results (63)

Phalaenopsis is a widely cultivated ornamental plant of considerable economic value worldwide. However, traditional growing medium, sphagnum moss, is limited and non-renewable. It also decomposes slowly and is prone to environmental issues. Therefore, there is an urgent need to identify more environmentally friendly and efficient alternatives. Biochar, a sustainable material with excellent physical and chemical properties, has been recognized as an effective promoter of plant growth. In this study, we investigated the influence of biochar derived from three raw materials (corn straw, bamboo, and walnut) mixed1 with coconut shell at ratios of 1:2, 1:10, and 4:1, on the growth of Phalaenopsis ‘Big Chili’. Over a 150-day controlled experiment, we evaluated multiple growth parameters, including plant height, crown width, total root length, total projected area, total surface area, and root volume. Compared to the traditional growing medium, the optimal biochar-coconut shell mixture (maize straw biochar: coconut shell = 1:2) increased plant height and crown width by 7.55% and 6.68%, respectively. Root metrics improved substantially, with total root length increasing by 10.96%, total projected area by 22.82%, total surface area by 22.14%, and root volume by 38.49%. Root biomass in the optimal treatment group increased by 42.47%, while aboveground and belowground dry weights increased by 6.16% and 77.11%, respectively. These improvements were closely associated with favorable substrate characteristics, including low bulk density, high total and water-holding porosity, moderate aeration, and adequate nutrient availability. These findings demonstrate that substrate characteristics critically influence plant performance and that biochar–coconut shell mixtures, particularly at a 1:2 ratio, represent a viable and sustainable alternative to sphagnum moss for commercial cultivation of Phalaenopsis. Full article

Phalaenopsis pulcherrima are known for their captivating floral morphology and diverse colors, demonstrate exceptional resilience to adverse environmental conditions, and exhibit significant potential for hybrid breeding. However, current research on flower coloration is still limited. The data from this study indicates that variations in anthocyanin levels are the primary determinants of the difference between white and purple colors. Through RNA-seq, we identified 469 genes that were differentially expressed. Furthermore, our bioinformatics exploration uncovered two potential transcription factors, PpMYB1 and PpbHLH1, which play regulatory roles in anthocyanin accumulation. Y2H assays demonstrated that these two TFs could form heterodimers and interact with each other. Afterwards, transient expression assays were conducted for the first time in P. pulcherrima flowers, revealing that overexpression of PpMYB1 alone or in combination with PpbHLH1 resulted in purple petal pigmentation. Overexpressing PpMYB1 in tobacco resulted in more purple-colored corollas, stamens, pistils, and pods compared to control plants. Y1H and dual-luciferase assays provided further evidence that PpMYB1 and PpbHLH1 interact with the promoters of the structural genes PpF3H, PpDFR, and PpANS in the anthocyanin biosynthesis pathway, thereby driving their robust expression. This study not only enhances our understanding of the molecular mechanisms underlying anthocyanin synthesis but also holds significant practical implications for advancing plant hybrid breeding and genetic engineering applications in flower color regulation. Full article

The Phalaenopsis genus, a horticulturally vital group within the Orchidaceae, dominates global floriculture markets through strategic cultivar innovation, scalable propagation, and data-driven cultivation. This review systematically examines the breeding, propagation, cultivation management, and potential applications of Phalaenopsis while providing insights into future research directions. The main contents include the following: Breeding innovations—This review outlines the taxonomy of the Phalaenopsis genus and highlights its intergeneric hybridization potential, which offers vast opportunities for developing novel horticultural varieties. By establishing clear breeding objectives, researchers employ diverse breeding strategies, including conventional crossbreeding and biotechnological approaches (e.g., mutation breeding, ploidy manipulation, genetic transformation, and CRISPR/Cas9 editing). Propagation and cultivation management—Analyses of Phalaenopsis tissue culture protocols covering explant selection, media optimization, and regeneration systems are summarized. Key factors for efficient cultivation are discussed, including temperature, light, water, nutrient management, cultivation medium selection, and integrated pest/disease management. Scientific environmental control ensures robust plant growth, synchronized flowering, and high-quality flower production. Emerging applications—Phalaenopsis exhibits promising applications in functional bioactive compound extraction (e.g., antioxidants and antimicrobial agents). This review summarizes current advancements in Phalaenopsis breeding, cultivation, and potential applications. Based on technological progress and market demands, future research directions are proposed to support the sustainable development of the Phalaenopsis industry. Full article

MADS-box transcription factors have undergone in-depth investigations regarding their function in regulating the development of plant floral organs. Flower type mutants serve as critical biological models for investigating the regulatory mechanisms of MADS-box genes in floral organ development, while simultaneously constituting essential genetic resources for molecular breeding programs. In this work, we examined a lip-like sepal of the peloric mutant in Phalaenopsis ‘Huayang’, which exhibited changes in both the morphology and color of the sepals. Our cryo-SEM investigations revealed that the mutation type belonged to a sepal labellum-like variation in Phalaenopsis ‘Huayang’. Nine glycosylated anthocyanins were identified and their contents were significantly upregulated in the Se-red of mutant flowers. Transcriptomic analysis identified 9408 differentially expressed genes, including 4934 upregulated and 4474 downregulated genes. In addition, 57 MADS-box genes were identified and classed into five groups (Mα, Mβ, Mγ, MIKC*, and MIKC^C) according to a phylogenetic comparison with Arabidopsis homologs. Furthermore, 29 MADS genes were screened from the MIKC^C group, and these genes may play a crucial role in the regulation of floral organ development. Through real-time PCR analysis and protein interaction analysis, we identified three genes that were upregulated in the mutant, which may be involved in sepal development. The subcellular localization results demonstrated that three genes were found within the nucleus. Taken together, our results elucidated the molecular mechanism of sepal variation in Phalaenopsis ‘Huayang’. Our results could enhance our comprehension of the regulatory mechanisms underlying floral patterning and promote the molecular breeding process of Phalaenopsis. Full article

Phalaenopsis-type Dendrobium (Den-Phals) is a commercially valuable orchid, with floral color being key to its market appeal. Despite the significance of anthocyanin biosynthesis in color development, its transcriptional regulation in Den-Phals remains unclear. This study functionally characterized the promoters of DhMYB2 and DhbHLH1, two key transcription factors involved in anthocyanin biosynthesis. A 1864 bp DhMYB2 promoter and a 1995 bp DhbHLH1 promoter were isolated using genome walking. Bioinformatics analysis identified cis-acting elements associated with abiotic stress responses, phytohormone signaling, and floral-specific regulation. 5′-Deletion analysis in tobacco leaves identified core regulatory regions for the DhMYB2 promoter (−1864 to −937 bp) and DhbHLH1 promoter (−1995 to −924 bp). GUS staining and activity assays demonstrated that the activities of the DhMYB2 and DhbHLH1 promoters were significantly increased under treatments of long light, low temperature, drought, salicylic acid (SA), and abscisic acid (ABA), while the DhbHLH1 promoter was also induced by methyl jasmonate (MeJA) and indole-3-acetic acid (IAA). Furthermore, promoter activity of DhMYB2 and DhbHLH1 was detected only in transgenic Arabidopsis flowers, suggesting that these promoters exhibit floral-specific activity. This study provides the first functional analysis of Den-Phals anthocyanin promoters, revealing their stress-responsive nature and floral specificity, which will facilitate molecular breeding of novel orchid cultivars. Full article

Soft rot caused by Dickeya fangzhongdai is a destructive disease in Phalaenopsis production that seriously impacts the quality and yield of Phalaenopsis. To explore the molecular mechanisms underlying disease resistance, transcriptome analysis was conducted on resistant and susceptible Phalaenopsis varieties. By comparing the transcriptomes of the resistant variety ‘ES L20’ and the susceptible variety ‘Zishuijing’ after D. fangzhongdai infection, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed. The results revealed that the differentially expressed genes were mainly enriched in pathways related to plant–pathogen interaction, plant hormone signal transduction, and the phenylpropanoid biosynthetic pathway. In the resistant variety ‘ES L20’, some genes in the Ca²⁺ pathway, PAMP-triggered immunity pathway, and Effector-triggered immunity pathway were significantly up-regulated. Analysis of the transcriptome levels of genes in the phytohormone-related pathways showed that genes associated with IAA (indole-3-acetic acid), salicylic acid, and jasmonic acid signal transduction pathways were all up-regulated in the resistant variety after inoculation. Furthermore, the analysis of genes in the phenylpropanoid biosynthesis pathway demonstrated significant up-regulation in the resistant variety. The determination of lignin content validated this result, confirming the crucial role of lignin synthesis in Phalaenopsis defense against soft rot. These findings suggest that the differentially expressed genes in phytopathogenic interaction pathways, along with those involved in hormone-related and lignin synthesis pathways, play important roles in Phalaenopsis resistance to soft rot. This study provides valuable insights into the molecular basis of Phalaenopsis resistance to soft rot and may contribute to the development of effective disease control strategies. Full article

The formation of flower color is closely related to anthocyanin synthesis. In this study, flowers of Bletilla striata (Orchidaceae) exhibiting distinct color morphs were collected and analyzed. The HPLC results showed significantly higher total flavonoid and anthocyanin contents in purple flowers compared to pink counterparts, with increases of 2.20-fold (p < 0.01) and 15.22-fold (p < 0.01), respectively. Cyanidin was the predominant anthocyanin in B. striata. Resequencing analyses highlighted SNP as the primary variation associated with color divergence. A comprehensive screen identified 61 genes encoding enzymes critical to the flavonoid and anthocyanin biosynthesis pathways in B. striata. Among these, 16 flower-specific genes exhibited high expression levels and harbored SNP variations. Notably, a premature stop codon was identified in a gene encoding dihydroflavonol 4-reductase (DFR), leading to truncated protein synthesis and potential disruption of anthocyanin production. Further, the heterologous overexpression of BsDFR4 in Phalaenopsis aphrodite changed petal color from white to yellow-green, demonstrating that it indeed played a regulatory role in the formation of flower color. Furthermore, yeast one-hybrid assays confirmed that transcription factors BsMYB36 and BsMYB51 could directly bind to the BsDFR4 promoter, suggesting their synergistic regulation of anthocyanin biosynthesis. These results provided a conceptual basis for insights into the formation of different flower colors in Orchidaceae. Full article

Danxiaorchis yangii is a fully mycoheterotrophic orchid that lacks both leaves and roots, belonging to the genus Danxiaorchis in the subtribe Calypsoinae. In this study, we assembled and annotated its mitochondrial genome (397,867 bp, GC content: 42.70%), identifying 55 genes, including 37 protein-coding genes (PCGs), 16 tRNAs, and 2 rRNAs, and conducted analyses of relative synonymous codon usage (RSCU), repeat sequences, horizontal gene transfers (HGTs), and gene selective pressure (dN/dS). Additionally, we sequenced and assembled its plastome, which has a reduced size of 110,364 bp (GC content: 36.60%), comprising 48 PCGs, 26 tRNAs, and 4 rRNAs. We identified 64 potential chloroplast DNA fragments transferred to the mitogenome. Phylogenomic analysis focusing on 33 mitogenomes, with Vitis vinifera as the outgroup, indicated that D. yangii is grouped as follows: D. yangii + ((Dendrobium wilsonii + Dendrobium wilsonii henanense) + Phalaenopsis aphrodite). Phylogenetic analysis based on 83 plastid PCGs from these species showed that D. yangii is grouped as follows: (D. yangii + Pha. aphrodite) + (Den. wilsonii + Den. henanense). Gene selective pressure analysis revealed that most mitochondrial and plastid genes in D. yangii are under purifying selection, ensuring functional stability, and certain genes may have undergone positive selection or adaptive evolution, reflecting the species’ adaptation to specific ecological environments. Our study provides valuable data on the plastomes and mitogenomes of D. yangii and lays the groundwork for future research on genetic variation, evolutionary relationships, and the breeding of orchids. Full article

Aluminum-activated malate transporter (ALMT) genes play an important role in aluminum ion (Al³⁺) tolerance, fruit acidity, and stomatal movement. Although decades of research have been carried out in many plants, there is little knowledge about the roles of ALMT in Orchidaceae. In this study, 34 ALMT genes were identified in the genomes of four orchid species. Specifically, ten ALMT genes were found in Dendrobium chrysotoxum and D. catenatum, and seven were found in Apostasia shenzhenica and Phalaenopsis equestris. These ALMT genes were further categorized into four clades (clades 1–4) based on phylogenetic relationships. Sequence alignment and conserved motif analysis revealed that most orchid ALMT proteins contain conserved regions (TM1, GABA binding motif, and WEP motif). We also discovered a unique motif (19) belonging to clade 1, which can serve as a specifically identified characteristic. Comparison with the gene structure of AtALMT genes (Arabidopsis thaliana) showed that the gene structure of ALMT was conserved across species, but the introns were longer in orchids. The promoters of orchid ALMT genes contain many light-responsive and hormone-responsive elements, suggesting that their expression may be regulated by light and phytohormones. Chromosomal localization and collinear analysis of D. chrysotoxum indicated that tandem duplication (TD) is the main reason for the difference in the number of ALMT genes in these orchids. D. catenatum was chosen for the RT-qPCR experiment, and the results showed that the DcaALMT gene expression pattern varied in different tissues. The expression of DcaALMT1-9 was significantly changed after ABA treatment. Combining the circadian CO₂ uptake rate, titratable total acid, and RT-qPCR data analysis, most DcaALMT genes were highly expressed at night and around dawn. The result revealed that DcaALMT genes might be involved in photosynthate accumulation. The above study provides more comprehensive information for the ALMT gene family in Orchidaceae and a basis for subsequent functional analysis. Full article

Low temperatures are the most significant abiotic stressor for the conservation and production of Phalaenopsis in non-tropical areas. CBF/DREB1 transcription factors play an important role in the plant abiotic stress response. In this study, 31 DREB family members were identified in the Phalaenopsis genome. Expression pattern analysis showed that the expression of different PaDREB members varied among tissue sites. PaDREB1D was isolated from Phalaenopsis aphrodite, and multiple sequence alignment showed that PaDREB1D belonged to the A1 subgroup of the DREB family and was localized in the nucleus. PaDREB1D overexpression in protocorm-like bodies of Phalaenopsis reduced cell damage during low-temperature stress, increased antioxidant enzyme activity, and enhanced the low-temperature tolerance of protocorm-like bodies. The results of this study provide a theoretical basis for breeding for cold resistance and investigating the molecular mechanisms related to low-temperature responses in Phalaenopsis. Full article

Phalaenopsis is the most popular potted plant worldwide. However, its typically long stalks often lead to increased shipping costs and risks. This study investigates the effectiveness of varying the concentration, timing, and frequency of paclobutrazol (PP333) applications on shortening the stalk of Phalaenopsis Join Grace ‘TH288-4’. Concurrently, it also examines the potential for producing visually appealing and single-flower potted phalaenopsis products by means of truncation. Mature phalaenopsis plants were moved to a cool room in the seventh week to induce flowering. Four experimental groups were established based on different PP333 application schedules: the control (CK) group, with reverse osmosis water application in the second week; the T2 group, with a single application in the second week; the T2T3 group, with applications in both the second and third weeks; and the T7T8 group, with applications in the seventh and eighth weeks. The PP333 concentrations used were 250, 500, 750, and 1000 mg·L⁻¹, applied as foliar sprays. The results showed that the shortest stalks, measured from the base to the first flower, were observed in the T2 group treated with PP333 at 750 mg·L⁻¹ and in the T2T3 group with PP333 at 500, 750, and 1000 mg·L⁻¹. These treatments resulted in stalk lengths of 19.18–22.17 cm, which are 67.2–71.6% shorter than the controls. PP333 application had minimal effect on the stalk diameter, pedicel length, flower width, length, and length/width ratio. However, root diameter was thicker in plants treated with PP333 compared with the control plants. For producing single-flower phalaenopsis, a foliar spray of 750 mg·L⁻¹ PP333 is recommended approximately a month before moving the plants to cooler conditions, followed by truncation, retaining only the first flower. As a result, this study establishes a PP333 treatment protocol for phalaenopsis, offering a strategy to effectively shorten the stalks. Full article

Phalaenopsis orchids, with their unique appearance and extended flowering period, are among the most commercially valuable Orchidaceae worldwide. Particularly, the variegation in leaf color of Phalaenopsis significantly enhances the ornamental and economic value and knowledge of the molecular mechanism of leaf-color variegation in Phalaenopsis is lacking. In this study, an integrative analysis of the physiology, cytology, and transcriptome profiles was performed on Phalaenopsis Chia E Yenlin Variegata leaves between the green region (GR) and yellow region (YR) within the same leaf. The total chlorophyll and carotenoid contents in the YR exhibited a marked decrease of 72.18% and 90.21%, respectively, relative to the GR. Examination of the ultrastructure showed that the chloroplasts of the YR were fewer and smaller and exhibited indistinct stromal lamellae, ruptured thylakoids, and irregularly arranged plastoglobuli. The transcriptome sequencing between the GR and YR led to a total of 3793 differentially expressed genes, consisting of 1769 upregulated genes and 2024 downregulated genes. Among these, the chlorophyll-biosynthesis-related genes HEMA, CHLH, CRD, and CAO showed downregulation, while the chlorophyll-degradation-related gene SGR had an upregulated expression in the YR. Plant-hormone-related genes and transcription factors MYBs (37), NACs (21), ERFs (20), bHLH (13), and GLK (2), with a significant difference, were also analyzed. Furthermore, qRT-PCR experiments validated the above results. The present work establishes a genetic foundation for future studies of leaf-pigment mutations and may help to improve the economic and breeding values of Phalaenopsis. Full article

Hemerocallis citrina Baroni (H. citrina) is an important specialty vegetable that is not only edible and medicinal but also has ornamental value. However, much remains unknown about the regulatory mechanisms associated with the growth, development, and flowering rhythm of this plant. CO, as a core regulatory factor in the photoperiod pathway, coordinates light and circadian clock inputs to transmit flowering signals. We identified 18 COL genes (HcCOL1-HcCOL18) in the H. citrina cultivar ‘Mengzihua’ and studied their chromosomal distribution, phylogenetic relationships, gene and protein structures, collinearity, and expression levels in the floral organs at four developmental stages. The results indicate that these genes can be classified into three groups based on phylogenetic analysis. The major expansion of the HcCOL gene family occurred via segmental duplication, and the Ka/Ks ratio indicated that the COL genes of Arabidopsis thaliana, Oryza sativa, Phalaenopsis equestris, and H. citrina were under purifying selection. Many cis-elements, including light response elements, abiotic stress elements, and plant hormone-inducible elements, were distributed in the promoter sequences of the HcCOL genes. Expression analysis of HcCOL genes at four floral developmental stages revealed that most of the HcCOL genes were expressed in floral organs and might be involved in the growth, development, and senescence of the floral organs of H. citrina. This study lays a foundation for the further elucidation of the function of the HcCOL gene in H. citrina and provides a theoretical basis for the molecular design breeding of H. citrina. Full article

Fluorinated cytokinins have emerged as promising alternatives to traditional cytokinins in Phalaenopsis plant tissue culture, offering enhanced stability and bioactivity. However, their metabolic fate and impact on endogenous cytokinin profiles remain largely unexplored. This study builds upon previous research to investigate the comparative metabolism of the traditional cytokinin 6-Benzylaminopurine (BA) with the successful alternatives 6-(3-fluorobenzylamino)purine (FmT) and 6-(3-fluorobenzylamino)purine 9-riboside (FmTR). Additionally, this study examines the impact of another crucial factor, the use of ventilated versus closed containers, on metabolic processes. The results revealed the distinct metabolic profiles associated with each treatment, highlighting the complex interplay between exogenous and endogenous cytokinin levels. This study is the first to investigate the effects of these stable, synthetic, and exogenous cytokinins on the naturally occurring cytokinin levels and their metabolites in micropropagated Phalaenopsis. Additionally, we proposed an alternative inactivation pathway involving the conversion of FmTR and BA to pT and pTR. These findings provide valuable insights into the intricate relationship between cytokinin metabolism and plant growth under in vitro conditions. Full article

Taeniophyllum is a distinct taxon of epiphytic leafless plants in the subtribe Aeridinae of Orchidaceae. The differences in chloroplast genomes between extremely degraded epiphytic leafless orchids and other leafy orchids, as well as their origins and evolution, raise intriguing questions. Therefore, we report the chloroplast genome sequence of Taeniophyllum complanatum, including an extensive comparative analysis with other types of leafless orchids. The chloroplast genome of T. complanatum exhibited a typical quadripartite structure, and its overall structure and gene content were relatively conserved. The entire chloroplast genome was 141,174 bp in length, making it the smallest known chloroplast genome of leafless epiphytic orchids. It encoded a total of 120 genes, including repetitive genes, comprising 74 protein-coding genes, 38 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. A phylogenetic analysis was conducted on the chloroplast genomes of 43 species belonging to five subfamilies of Orchidaceae. The results showed that the five subfamilies were monophyly, with nearly all segments having a 100% bootstrap value. T. complanatum and Chiloschista were clustered together as a sister group to Phalaenopsis and occupied the highest position in the Epidendroideae. Phylogenetic analysis suggested that T. complanatum and other leafless orchids within the Orchidaceae evolved independently. This study may provide the foundation for research on phylogenetic and structural diversity in leafless epiphytic orchids, thereby enhancing the resources available for chloroplast genome studies in Orchidaceae. Full article