Horticulturae

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16 pages, 16505 KiB

Open AccessArticle

Delayed Starch Degradation Triggers Chromoplast Structural Aberration to Inhibit Carotenoid Cleavage: A Novel Mechanism for Flower Color Deepening in Osmanthus fragrans

by Xiangling Zeng, Yunfei Tan, Xin Wen, Qiang He, Hui Wu, Jingjing Zou, Jie Yang, Xuan Cai and Hongguo Chen

Horticulturae 2025, 11(7), 864; https://doi.org/10.3390/horticulturae11070864 - 21 Jul 2025

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Abstract

The color of flowers in Osmanthus fragrans is regulated by carotenoid metabolism. The orange-red variety, Dangui, is believed to have evolved from the yellow variety, Jingui, through a natural bud mutation. This study uses the Jingui cultivar ‘Jinqiu Gui’ (JQG) and its bud [...] Read more.

The color of flowers in Osmanthus fragrans is regulated by carotenoid metabolism. The orange-red variety, Dangui, is believed to have evolved from the yellow variety, Jingui, through a natural bud mutation. This study uses the Jingui cultivar ‘Jinqiu Gui’ (JQG) and its bud mutation cultivar ‘Huolian Jindan’ (HLJD) as materials, combining genome resequencing, ultrastructural observation, targeted metabolomics, and transcriptomic analysis to elucidate the molecular and cellular mechanisms underlying flower color variation. Phylogenetic analysis confirms that HLJD is a natural bud mutation of JQG. Ultrastructural observations reveal that during petal development, chromoplasts are transformed from proplastids. In HLJD petals, starch granules degrade more slowly and exhibit abnormal morphology, resulting in chromoplasts displaying crystalline, tubular, and fibrous composite structures, in contrast to the typical spherical plastoglobuli found in JQG. Targeted metabolomics identified 34 carotenoids, showing significant increases in the levels of ε-carotene, γ-carotene, α-carotene, and β-carotene in HLJD petals compared to JQG, with these levels continuing to accumulate throughout the flowering process, while the levels of the cleavage products α-ionone and β-ionone decrease. Transcriptomic analysis indicates that carotenoid metabolic pathway genes do not correlate directly with the phenotype; however, 49 candidate genes significantly associated with pigment accumulation were identified. Among these, the expression of genes such as glycoside hydrolases (LYG036752, etc.), sucrose synthase (LYG010191), and glucose-1-phosphate adenylyltransferase (LYG003610) are downregulated in HLJD. This study proposes for the first time the pathway of “starch degradation delay → chromoplast structural abnormalities → carotenoid cleavage inhibition” for deepening flower color, providing a new theoretical model for the metabolic regulation of carotenoids in non-photosynthetic tissues of plants. This research not only identifies key target genes (such as glycoside hydrolases) for the color breeding of O. fragrans but also establishes a theoretical foundation for the color enhancement of other ornamental plants. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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19 pages, 35006 KiB

Open AccessArticle

The Comprehensive Root Metabolite–Rhizomicrobiota Response Patterns of Rhododendron delavayi (R. delavayi) to Waterlogging Stress and Post–Waterlogging Recovery

by Jing Tang, Qingqing Huang, Qian Wang, Fei Shan, Shaolong Wu, Ximin Zhang, Ming Tang and Yin Yi

Horticulturae 2025, 11(7), 770; https://doi.org/10.3390/horticulturae11070770 - 2 Jul 2025

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Abstract

Waterlogging is a critical abiotic stressor that significantly impacts plant growth. Plants under waterlogging stress release metabolic signals that recruit rhizosphere microorganisms and enhance stress resistance. However, the mechanisms through which the non-adaptive species R. delavayi responds to waterlogging stress via the synergistic [...] Read more.

Waterlogging is a critical abiotic stressor that significantly impacts plant growth. Plants under waterlogging stress release metabolic signals that recruit rhizosphere microorganisms and enhance stress resistance. However, the mechanisms through which the non-adaptive species R. delavayi responds to waterlogging stress via the synergistic interaction between root metabolites and rhizosphere microbiota remain poorly elucidated. Here, we employed pot experiments to characterize the responses of the root metabolite–microbiota complex in R. delavayi during waterlogging stress and subsequent recovery. Our results revealed that waterlogging altered the root morphology, the root metabolite profile, rhizosphere microbial diversity and network complexity, and these effects persisted during recovery. A significant correlation between root metabolites and the rhizosphere microbial community structure during waterlogging stress and recovery. Importantly, some differentially accumulated metabolites had significant effects on the assembly of rhizosphere microbes. Most of the core microbes in the rhizosphere microbial community under waterlogging and post–waterlogging recovery treatment were likely beneficial bacteria. Based on these findings, we propose a model for how root metabolites and rhizosphere microbes interact to help R. delavayi cope with waterlogging and recover. Based on these findings, we propose a possible response pattern of root metabolites and rhizosphere microbiota complex in R. delavayi under waterlogging stress and recovery. This work provides new insights into the synergistic mechanisms enhancing plant waterlogging tolerance and highlights the potential of harnessing rhizosphere microbiota to improve resilience in rhododendrons. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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17 pages, 7981 KiB

Open AccessArticle

Genome-Wide Identification and Pollen-Specific Promoter Analysis of the DIR Gene Family in Rosa chinensis

by Qijing Dong, Qian Yang, Zitong Wang, Yuan Zhao, Sixu Guo, Yifang Peng, Qi Li and Yu Han

Horticulturae 2025, 11(7), 717; https://doi.org/10.3390/horticulturae11070717 - 20 Jun 2025

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Abstract

Dirigent proteins (DIRs) are pivotal regulators of lignin/lignan biosynthesis and play multifaceted roles in plant development and stress adaptation. Despite their functional significance, DIR genes remain unexplored in Rosa chinensis, a globally important woody ornamental species. This study identified 33 RcDIRs through [...] Read more.

Dirigent proteins (DIRs) are pivotal regulators of lignin/lignan biosynthesis and play multifaceted roles in plant development and stress adaptation. Despite their functional significance, DIR genes remain unexplored in Rosa chinensis, a globally important woody ornamental species. This study identified 33 RcDIRs through whole-genome analysis, including their chromosomal distribution, phylogenetic relationships, collinearity, protein and gene structure, conserved motifs, and cis-acting element distribution, and classified them into three phylogenetically independent subgroups (DIR-a, DIR-b/d, and DIR-e). Notably, the DIR-e subgroup includes an exclusive tandem cluster comprising RcDIR7-RcDIR12, representing the largest lineage-specific RcDIR expansion in R. chinensis. Structural characterization revealed that most RcDIRs exhibit a conserved single-exon architecture. Promoter cis-element analysis uncovered abundant stress-/hormone-responsive elements and three pollen-specific motifs (AAATGA, POLLEN1LELAT52, GTGANTG10), with RcDIR12 from the DIR-e cluster showing high pollen-specific regulatory potential. Experimental validation included cloning the RcDIR12 promoter from R. chinensis ‘Old Blush’, constructing proRcDIR12::GUS vectors, and conducting histochemical GUS assays with pollen viability/DAPI staining in transgenic Arabidopsis. Histochemical assays demonstrated GUS activity localization in mature trinucleate pollen grains, marking the first experimental evidence of pollen-specific DIRs in rose. Our findings not only elucidate the DIR family’s genomic organization and evolutionary innovations in R. chinensis but also establish proRcDIR12 as a molecular tool for manipulating pollen development in plants. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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19 pages, 2796 KiB

Open AccessArticle

Terpene Synthase (TPS) Family Member Identification and Expression Pattern Analysis in Flowers of Dendrobium chrysotoxum

by Yanni Yang, Jianying Gong, Rongrong Nong, Qiao Liu, Ke Xia, Shuo Qiu and Zaihua Wang

Horticulturae 2025, 11(6), 566; https://doi.org/10.3390/horticulturae11060566 - 22 May 2025

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Abstract

Flower fragrance is a crucial ornamental and economic trait of Dendrobium chrysotoxum, and the most abundant and diverse aroma-active compounds are terpenes. Terpene synthase (TPS) is the ultimate enzyme for the biosynthesis of various types of terpenes, and TPS genes were identified [...] Read more.

Flower fragrance is a crucial ornamental and economic trait of Dendrobium chrysotoxum, and the most abundant and diverse aroma-active compounds are terpenes. Terpene synthase (TPS) is the ultimate enzyme for the biosynthesis of various types of terpenes, and TPS genes were identified as the key regulators governing the spatiotemporal release of volatile terpene compounds. Until recently, the TPS gene family in D. chrysotoxum has remained largely unexplored. Our study characterizes the TPS genes in D. chrysotoxum and identifies 37 DcTPS gene family members. It helped identify the DcTPS genes, gene characteristics, the phylogeny relationship, conserved motif location, gene exon/intron structure, cis-elements in the promoter regions, protein–protein interaction (PPI) network, tissue specific expression and verification of the expression across different flowering stages and floral organs. Three highly expressed DcTPS genes were cloned, and their functions were verified using a transient expressed in tobacco leaves. Further functional verification showed that the proteins encoded by these genes were enzymes involved in monoterpene synthesis, and they were all involved in the synthesis of linalool. This study comprehensively expatiates on the TPS gene family members in D. chrysotoxum for the first time. These data will help us gain a deeper understanding of both the molecular mechanisms and the effects of the TPS genes. Furthermore, the discovery that three TPS-b genes (DcTPS 02, 10, 32) specifically drive linalool-based scent in D. chrysotoxum, will provide new insights for expanding the TPS-b subfamily in orchids and identifying the linalool synthases contributing to orchid fragrance. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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18 pages, 17742 KiB

Open AccessArticle

Comparative Transcriptomic Analysis of Pyrethrin and EβF Biosynthesis in Tanacetum cinerariifolium Stems and Flowers

by Tuo Zeng, Jiawen Li, Caiyun Wang and Jinjin Li

Horticulturae 2025, 11(2), 201; https://doi.org/10.3390/horticulturae11020201 - 13 Feb 2025

Viewed by 823

Abstract

Tanacetum cinerariifolium, a perennial Asteraceae plant, is renowned for its ornamental value and natural insecticidal compounds, especially pyrethrins. These compounds, primarily stored in flower heads, are highly effective as insecticides with low toxicity to mammals, making them crucial for organic agriculture, along [...] Read more.

Tanacetum cinerariifolium, a perennial Asteraceae plant, is renowned for its ornamental value and natural insecticidal compounds, especially pyrethrins. These compounds, primarily stored in flower heads, are highly effective as insecticides with low toxicity to mammals, making them crucial for organic agriculture, along with the sesquiterpene (E)-β-farnesene (EβF), play critical roles in T. cinerariifolium defense mechanisms. However, the spatiotemporal patterns of these secondary metabolites in stems and flower heads, as well as their regulatory mechanisms, remain unclear. This study investigated the biosynthesis and regulation of pyrethrins and EβF across developmental stages (S1–S4) in flowers and stems using GC-MS and transcriptomics. Transcriptome analysis revealed that the expression of pyrethrin biosynthetic genes was not synchronized with pyrethrin accumulation. The main pyrethrin biosynthetic genes exhibited coordinated expression patterns, peaking during early flowering stages (S1–S2), while pyrethrin accumulation was primarily observed during mid-flower development. In contrast, the biosynthetic genes of EβF showed synchronized expression with EβF accumulation, with the highest activity observed in stems and early flowers. WGCNA identified jasmonic acid signaling, trichome differentiation, and terpene transport pathways as potentially associated with pyrethrin biosynthesis. Hub genes including MYC2 were identified as playing pivotal roles in regulating secondary metabolite biosynthesis. These findings provide new insights into the regulation and biosynthesis of pyrethrins and EβF, offering a foundation for optimizing bioactive compound production and advancing sustainable pest management strategies. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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14 pages, 3332 KiB

Open AccessArticle

Identification of Key Candidate Genes Involved in Aluminum Accumulation in the Sepals of Hydrangea macrophylla

by Shuwen Luo, Ying Li, Yibing Wan, Youwei Fan, Chun Liu and Suxia Yuan

Horticulturae 2024, 10(11), 1180; https://doi.org/10.3390/horticulturae10111180 - 7 Nov 2024

Cited by 2 | Viewed by 1371

Abstract

Hydrangea macrophylla (H. macrophylla), a species in the genus Hydrangea in the family Hydrangeaceae, is widely valued for its ornamental qualities in both domestic and international markets. Notably, H. macrophylla is known for its ability to accumulate aluminum (Al). Moreover, aluminum [...] Read more.

Hydrangea macrophylla (H. macrophylla), a species in the genus Hydrangea in the family Hydrangeaceae, is widely valued for its ornamental qualities in both domestic and international markets. Notably, H. macrophylla is known for its ability to accumulate aluminum (Al). Moreover, aluminum ions (Al³⁺) participate in sepal bluing. However, the underlying mechanisms of Al accumulation in the sepals remain unclear. In this study, we utilized transcriptome data from two cultivars to identify genes associated with Al accumulation. In total, 154 differentially expressed isoforms between the CK and Tr groups in the sepals of both cultivars were screened. Through gene enrichment analysis and similarity identification in the CDS (coding sequence) region, 43 differentially expressed genes were identified, including 30 upregulated and 13 downregulated genes, in the sepals of the Al treatment group. Further analysis revealed that seven of these upregulated genes are related to Al accumulation in sepals. Among the seven, the gene HmALS3.1 was identified as a potential key player in Al transport within the sepals of H. macrophylla. This study lays the groundwork for further exploration into the mechanisms by which HmALS3.1 regulates Al accumulation in H. macrophylla. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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16 pages, 5746 KiB

Open AccessArticle

Bioinformatics Analysis and Expression Features of Terpene Synthase Family in Cymbidium ensifolium

by Mengyao Wang, Baojun Liu, Jinjin Li, Ningzhen Huang, Yang Tian, Liting Guo, Caiyun Feng, Ye Ai and Chuanming Fu

Horticulturae 2024, 10(10), 1015; https://doi.org/10.3390/horticulturae10101015 - 24 Sep 2024

Cited by 1 | Viewed by 1257

Abstract

Terpene synthases (TPSs) are crucial for the diversification of terpenes, catalyzing the formation of a wide variety of terpenoid compounds. However, genome-wide systematic characterization of TPS genes in Cymbidium ensifolium has not been reported. Within the genomic database of C. ensifolium, we found 30 [...] Read more.

Terpene synthases (TPSs) are crucial for the diversification of terpenes, catalyzing the formation of a wide variety of terpenoid compounds. However, genome-wide systematic characterization of TPS genes in Cymbidium ensifolium has not been reported. Within the genomic database of C. ensifolium, we found 30 CeTPS genes for this investigation. CeTPS genes were irregularly distributed throughout the seven chromosomes and primarily expanded through tandem duplications. The CeTPS proteins were classified into three TPS subfamilies, including 17 TPS-b members, 8 TPS-a members, and 5 TPS-c members. Conserved motif analysis showed that most CeTPSs contained DDxxD and RRX₈W motifs. Cis-element analysis of CeTPS gene promoters indicated regulation primarily by plant hormones and stress. Transcriptome analysis revealed that CeTPS1 and CeTPS18 had high expression in C. ensifolium flowers. qRT-PCR results showed that CeTPS1 and CeTPS18 were predominantly expressed during the flowering stage. Furthermore, CeTPS1 and CeTPS18 proteins were localized in the chloroplasts. These results lay the theoretical groundwork for future research on the functions of CeTPSs in terpenoid biosynthesis. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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14 pages, 2833 KiB

Open AccessArticle

Transcriptomic Analysis Reveals Calcium and Ethylene Signaling Pathway Genes in Response to Cold Stress in Cinnamomum camphora

by Bo Bi, Lingmei Shao, Tong Xu, Hao Du and Danqing Li

Horticulturae 2024, 10(9), 995; https://doi.org/10.3390/horticulturae10090995 - 20 Sep 2024

Cited by 2 | Viewed by 1519

Abstract

Cinnamomum camphora is one of the most dominant broad-leaved evergreen trees in tropical and subtropical regions. Understanding its response to cold stress is crucial for enhancing its resilience to climate changes and expanding the cultivation range. Cold stress response is a vital strategy [...] Read more.

Cinnamomum camphora is one of the most dominant broad-leaved evergreen trees in tropical and subtropical regions. Understanding its response to cold stress is crucial for enhancing its resilience to climate changes and expanding the cultivation range. Cold stress response is a vital strategy for plants to withstand cold stress, typically involving transcriptional changes across various pathways. In this study, RNA-Sequencing (RNA-Seq) was conducted on the leaves of C. camphora subjected to different cold stress treatments (0 h, 2 h, and 12 h). Transcriptome analyses revealed that short-term cold stress treatment rapidly induced the upregulation of genes associated with calcium and ethylene signaling pathways, including GLR2.7, CaM, CPK7, and ERF1/3/4/5/7. Subsequently, 12 h cold response treatment further activated genes related to the cold response, jasmonic acid signaling pathways, and the negative regulation of cellular biosynthetic processes, such as CBF2 and CBF4. Notably, ERFs emerged as the most differentially expressed transcription factors in this study. A total of 133 ERF family members from C. camphora were identified through phylogenetic analysis, and these ERFs were classified into 12 clusters. Many of these ERFs are likely to play pivotal roles in the cold response of C. camphora, especially ERF1/3/4/5/7. These findings offer novel insights into the mechanisms underlying the cold response and present valuable candidates for further research, advancing our understanding of plant responses to cold stress. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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19 pages, 3694 KiB

Open AccessArticle

Comprehensive Analysis of Microbiomes and Metabolomics Reveals the Mechanism of Adaptation to Cadmium Stress in Rhizosphere Soil of Rhododendron decorum subsp. Diaprepes

by Ming Tang, Lanlan Chen, Li Wang, Yin Yi, Jianfeng Wang, Chao Wang, Xianlei Chen, Jie Liu, Yongsong Yang, Kamran Malik and Jiyi Gong

Horticulturae 2024, 10(8), 884; https://doi.org/10.3390/horticulturae10080884 - 21 Aug 2024

Cited by 1 | Viewed by 1490

Abstract

The toxicity of cadmium (Cd) not only affects the growth and development of plants but also has an impact on human health. In this study, high-throughput sequencing and LC-MS were conducted to analyze the effect of CdCl₂ treatment on the microbial community [...] Read more.

The toxicity of cadmium (Cd) not only affects the growth and development of plants but also has an impact on human health. In this study, high-throughput sequencing and LC-MS were conducted to analyze the effect of CdCl₂ treatment on the microbial community and soil metabolomics of rhizosphere soil in Rhododendron decorum subsp. diaprepes. The results showed that CdCl₂ treatment reduced the quality of the rhizosphere soil by significantly decreasing the soil organic carbon (SOC) content, urease, and invertase activities, increasing the percentage of the exchangeable Cd fraction. CdCl₂ treatment did not significantly change the Chao1 and Shannon indices of bacterial and fungal communities in the rhizosphere soil. R. decorum was more likely to recruit Cd-resistant bacteria (e.g., Proteobacteria, Chloroflexi) and increase the abundance of Cd-resistant fungi (e.g., Basidiomycota, Rozellomycota). Moreover, CdCl₂ treatment decreased the content of secondary metabolites associated with plants’ resistance to Cd. Rhizosphere soil urease, invertase activities, alkaline phosphatase (ALP), SOC, total potassium (TK), Cd, and nitrate nitrogen (NN) were the main drivers of the composition of rhizosphere bacterial and fungal communities. CdCl₂ treatment weakened the relationships among bacterial/fungi, differential metabolites, and physicochemical properties in rhizosphere soil. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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14 pages, 3530 KiB

Open AccessArticle

Metabolomic and Transcriptomic Analysis of Unique Floral Coloration in Osmanthus fragrans Cultivars

by Shenni Wei, Jiang Wu, Ping Yu, Yunfei Tan, Qiang He, Jie Yang, Xuan Cai, Jingjing Zou, Hongguo Chen and Xiangling Zeng

Horticulturae 2024, 10(8), 801; https://doi.org/10.3390/horticulturae10080801 - 29 Jul 2024

Cited by 1 | Viewed by 1114

Abstract

The floral color phenotypes of Osmanthus fragrans cultivars range from light yellow to orange yellow, with ‘Yanzhi Hong’ being the only reported cultivar with a red color. However, the underlying reason for this unique floral coloration remains unclear. The study conducted targeted metabolomics [...] Read more.

The floral color phenotypes of Osmanthus fragrans cultivars range from light yellow to orange yellow, with ‘Yanzhi Hong’ being the only reported cultivar with a red color. However, the underlying reason for this unique floral coloration remains unclear. The study conducted targeted metabolomics and transcriptomics analyses on the petals of ‘Yanzhi Hong’ at both initial and peak flowering stages. Candidate gene expression was validated, and expression levels of the petals of three cultivars were compared using RT-qPCR. The results revealed the presence of 27 components in the petals of ‘Yanzhi Hong’, including 5 carotenoids, 8 xanthophylls, and 14 xanthophyll esters. Notably, lycopene was detected in abundance for the first time in O. fragrans cultivars. Carotenes accounted for 78.82 ± 3.17% and 91.19 ± 1.69% of the total carotenoid content in petals during the initial and peak flowering stages, respectively, with all carotene contents increasing during the peak flowering period. β-carotene, lycopene, and γ-carotene were identified as the top three carotene components in petals during both initial and full flowering stages. The unique blush red color of ‘Yanzhi Hong’ petals could be attributed to the low content of α-carotene and the rich accumulation of lycopene. Furthermore, a total of 1550 differentially expressed genes (DEGs) were identified in petals at the peak flowering stage relative to the initial flowering stage, with 1003 genes being downregulated and 547 genes being upregulated during the full flowering stage. There are 926 differentially expressed genes (DEGs) annotated in the Gene Ontology (GO) database. Among these DEGs, those that were downregulated and upregulated during the peak flowering period showed significant enrichment in carbohydrate metabolism and oxidation–reduction processes, respectively. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified 14 structural genes associated with phenylpropanoid biosynthesis and 7 structural genes linked to carotenoid biosynthesis. Expression levels of candidate genes involved in carotenoid biosynthesis were examined in the petals of three cultivars (‘Yanzhi Hong’, ‘Liuye Jingui’, and ‘Gecheng Dangui’) at both the initial and peak flowering stages. The results indicated that the decreased expression of LYG009054 (LYCE) and LYG018651 (LYCB) in ‘Yanzhi Hong’ resulted in higher lycopene accumulation and lower α-carotene content in the petals. This study offers valuable insights into the mechanisms underlying the unique flower color phenotype of O. fragrans, proving a basis for further research on carotenoid metabolism pathways and the breeding of new cultivars with a variety of flower colors in O. fragrans. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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17 pages, 978 KiB

Open AccessArticle

Resistances and Physiological Responses of Impatiens uliginosa to Copper Stress

by Jiapeng Zhu, Xinyi Li, Haiquan Huang and Meijuan Huang

Horticulturae 2024, 10(7), 751; https://doi.org/10.3390/horticulturae10070751 - 16 Jul 2024

Viewed by 1530

Abstract

The phytoremediation of soil and water that has been significantly contaminated with metals has potential ecological and economical ramifications, as well as the advantages of high efficiency, and is an environmentally friendly method of ecological pollution control. This study aimed to examine the [...] Read more.

The phytoremediation of soil and water that has been significantly contaminated with metals has potential ecological and economical ramifications, as well as the advantages of high efficiency, and is an environmentally friendly method of ecological pollution control. This study aimed to examine the impact of varying concentrations of Copper (Cu²⁺) (0, 5, 10, 15, 20, and 25 mg·L⁻¹) on the growth, development, physiology, biochemistry, mineral elements, and features of Cu²⁺ enrichment of Impatiens uliginosa. This plant is endemic to Yunnan Province in China and is a wetland species. The results showed that the root lengths, stem diameters, plant height, and stem and leaf biomass of I. uliginosa showed a phenomenon of “low promotion and high inhibition,” while the root biomass showed a trend of gradual decreasing. At the early stage of Cu²⁺ stress (day 6), the activities of peroxidase and catalase and the contents of malondialdehyde (MDA) of I. uliginosa were directly proportional to the concentration of Cu²⁺. As the treatment time increased, the activation of a defense mechanism in vivo enabled I. uliginosa to adapt to the high Cu²⁺ environment, and the content of MDA gradually decreased. As the concentration of Cu²⁺ increased, its contents in the roots, stems, and leaves also gradually increased. In particular, when the concentration of Cu²⁺ reached 25 mg·L⁻¹, its contents in the roots of I. uliginosa increased by 39.16-fold compared with that of the control group (CK). The concentration-dependent influence of the contents of iron (Fe) and zinc (Zn) in the roots and leaves were observed. Low concentrations of Cu²⁺ promoted iron content in roots and leaves, and vice versa, while Zn content decreased with the increasing concentration of Cu²⁺. It was conclusively shown that I. uliginosa has the potential to remediate low concentrations of Cu²⁺ pollution in water and is a textbook ornamental plant to remediate bodies of water that are polluted with Cu²⁺. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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14 pages, 3206 KiB

Open AccessArticle

Analysis of Transcriptome and Expression of C4H and FLS Genes on Four Flower Colors of Impatiens uliginosa

by Xiaoli Zhang, Yi Tan, Xinyi Li, Zengdong Liu, Fan Li, Haiquan Huang and Meijuan Huang

Horticulturae 2024, 10(4), 415; https://doi.org/10.3390/horticulturae10040415 - 19 Apr 2024

Cited by 3 | Viewed by 1486

Abstract

Flower color is a major feature of ornamental plants, and the rich flower color of plants is an important factor in determining their ornamental and economic values, so flower color is an important research target for gardening and horticulture breeders at home and [...] Read more.

Flower color is a major feature of ornamental plants, and the rich flower color of plants is an important factor in determining their ornamental and economic values, so flower color is an important research target for gardening and horticulture breeders at home and abroad. Our research group collected four colors of Impatiens uliginosa (white, pink, red, and deep red) during the collection of germplasm resources in the field. In this study, we analyzed the transcriptomes of the four flower colors of I. uliginosa by using RNA-Seq technology. The transcriptomes were screened to identify candidate genes related to flower color, and the coloring mechanisms of four flower colors were revealed at the molecular level. The main findings were as follows: (1) The number of the four different transcripts ranged from 64,723 to 93,522 and contained a total of 100,705 unigenes. (2) The analysis of differentially expressed genes revealed structural genes including C4H, FLS, PAL, and ANS and transcription factors including MYB, MYB-related, AP2-EREBP, and bHLH. (3) Among the four flower colors of I. uliginosa, the C4H1 gene had the highest expression in pink flowers, and the C4H2 gene had the highest expression in red flowers. This indicated that C4H genes positively regulated the red flower color of I. uliginosa. However, FLS expression was the highest in white flowers, and with deepening flower color, FLS gene expression gradually weakened, acting as a negative regulator. The results of this study could lay the theoretical foundation for investigating the mechanism of coloration and flower color variation in I. uliginosa. Full article

(This article belongs to the Special Issue Physiological and Molecular Biology of Ornamental Plants—2nd Edition)

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