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Lin Y, Qiu Z, Lin X, Wu Y, Niu X, Yin G, Shao D, Xiang X, Li Y, Yang C. The Role of MbEGS1 and MbEGS2 in Methyleugenol Biosynthesis by Melaleuca bracteata. PLANTS (BASEL, SWITZERLAND) 2023; 12:1026. [PMID: 36903887 PMCID: PMC10005710 DOI: 10.3390/plants12051026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
Many aromatic plant volatile compounds contain methyleugenol, which is an attractant for insect pollination and has antibacterial, antioxidant, and other properties. The essential oil of Melaleuca bracteata leaves contains 90.46% methyleugenol, which is an ideal material for studying the biosynthetic pathway of methyleugenol. Eugenol synthase (EGS) is one of the key enzymes involved in the synthesis of methyleugenol. We recently reported two eugenol synthase genes (MbEGS1 and MbEGS2) present in M. bracteata, where MbEGS1 and MbEGS2 were mainly expressed in flowers, followed by leaves, and had the lowest expression levels in stems. In this study, the functions of MbEGS1 and MbEGS2 in the biosynthesis of methyleugenol were investigated using transient gene expression technology and virus-induced gene silencing (VIGS) technology in M. bracteata. Here, in the MbEGSs genes overexpression group, the transcription levels of the MbEGS1 gene and MbEGS2 gene were increased 13.46 times and 12.47 times, respectively, while the methyleugenol levels increased 18.68% and 16.48%. We further verified the function of the MbEGSs genes by using VIGS, as the transcript levels of the MbEGS1 and MbEGS2 genes were downregulated by 79.48% and 90.35%, respectively, and the methyleugenol content in M. bracteata decreased by 28.04% and 19.45%, respectively. The results indicated that the MbEGS1 and MbEGS2 genes were involved in the biosynthesis of methyleugenol, and the transcript levels of the MbEGS1 and MbEGS2 genes correlated with the methyleugenol content in M. bracteata.
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Affiliation(s)
- Yongsheng Lin
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Natural Products of Horticultural Plants, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ziwen Qiu
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Natural Products of Horticultural Plants, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xiaojie Lin
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Natural Products of Horticultural Plants, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yingxiang Wu
- Qingyuan Agricultural Science and Technology Extension Service Center, Qingyuan 511518, China
| | - Xianqian Niu
- Fujian Institute of Tropical Crops, Zhangzhou 363001, China
| | - Guanwen Yin
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Natural Products of Horticultural Plants, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Dandan Shao
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Natural Products of Horticultural Plants, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xuwen Xiang
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Natural Products of Horticultural Plants, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yongyu Li
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Natural Products of Horticultural Plants, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chao Yang
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Institute of Natural Products of Horticultural Plants, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Yang G, Qin Y, Jia Y, Xie X, Li D, Jiang B, Wang Q, Feng S, Wu Y. Transcriptomic and metabolomic data reveal key genes that are involved in the phenylpropanoid pathway and regulate the floral fragrance of Rhododendron fortunei. BMC PLANT BIOLOGY 2023; 23:8. [PMID: 36600207 PMCID: PMC9814181 DOI: 10.1186/s12870-022-04016-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND To reveal the key genes involved in the phenylpropanoid pathway, which ultimately governs the fragrance of Rhododendron fortunei, we performed a comprehensive transcriptome and metabolomic analysis of the petals of two different varieties of two alpine rhododendrons: the scented R. fortunei and the unscented Rhododendron 'Nova Zembla'. RESULTS Our transcriptomic and qRT-PCR data showed that nine candidate genes were highly expressed in R. fortunei but were downregulated in Rhododendron 'Nova Zembla'. Among these genes, EGS expression was significantly positively correlated with various volatile benzene/phenylpropanoid compounds and significantly negatively correlated with the contents of various nonvolatile compounds, whereas CCoAOMT, PAL, C4H, and BALDH expression was significantly negatively correlated with the contents of various volatile benzene/phenylpropanoid compounds and significantly positively correlated with the contents of various nonvolatile compounds. CCR, CAD, 4CL, and SAMT expression was significantly negatively correlated with the contents of various benzene/phenylpropanoid compounds. The validation of RfSAMT showed that the RfSAMT gene regulates the synthesis of aromatic metabolites in R. fortunei. CONCLUSION The findings of this study indicated that key candidate genes and metabolites involved in the phenylpropanoid biosynthesis pathway may govern the fragrance of R. fortunei. This lays a foundation for further research on the molecular mechanism underlying fragrance in the genus Rhododendron.
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Affiliation(s)
- Guoxia Yang
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, Zhejiang, China
| | - Yi Qin
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, Zhejiang, China
| | - Yonghong Jia
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, Zhejiang, China
| | - Xiaohong Xie
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, Zhejiang, China
| | - Dongbin Li
- Ningbo Forest Farm, Ningbo, 315100, Zhejiang, China
| | - Baoxin Jiang
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, Zhejiang, China
| | - Qu Wang
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, Zhejiang, China
| | - Siyu Feng
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, Zhejiang, China
| | - Yueyan Wu
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, Zhejiang, China.
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Xiujun W, Zhenqi S, Yujing T, Kaifeng M, Qingwei L. Comparative transcriptome analysis linked to key volatiles reveals molecular mechanisms of aroma compound biosynthesis in Prunus mume. BMC PLANT BIOLOGY 2022; 22:395. [PMID: 35945501 PMCID: PMC9361687 DOI: 10.1186/s12870-022-03779-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 07/27/2022] [Indexed: 05/30/2023]
Abstract
BACKGROUND Mei (Prunus mume) is the only woody plant in the genus Prunus with a floral fragrance, but the underlying mechanisms of aroma compound biosynthesis are unclear despite being a matter of considerable interest. RESULTS The volatile contents of the petals of two cultivars with significantly different aromas, Prunus mume 'Xiao Lve' and Prunus mume 'Xiangxue Gongfen', were characterised by GC-MS at different flowering periods, and a total of 44 volatile compounds were detected. Among these, the main substances forming the typical aroma of P. mume were identified as eugenol, cinnamyl acetate, hexyl acetate and benzyl acetate, with variations in their relative concentrations leading to sensory differences in the aroma of the two cultivars. We compiled a transcriptome database at key stages of floral fragrance formation in the two cultivars and used it in combination with differential analysis of floral volatiles to construct a regulatory network for the biosynthesis of key aroma compounds. The results indicated that PmPAL enzymes and PmMYB4 transcription factors play important roles in regulating the accumulation of key biosynthetic precursors to these compounds. Cytochrome P450s and short-chain dehydrogenases/reductases might also influence the biosynthesis of benzyl acetate by regulating production of key precursors such as benzaldehyde and benzyl alcohol. Furthermore, by analogy to genes with verified functions in Arabidopsis, we predicted that three PmCAD genes, two 4CL genes, three CCR genes and two IGS genes all make important contributions to the synthesis of cinnamyl acetate and eugenol in P. mume. This analysis also suggested that the downstream genes PmBGLU18-like, PmUGT71A16 and PmUGT73C6 participate in regulation of the matrix-bound and volatile states of P. mume aroma compounds. CONCLUSIONS These findings present potential new anchor points for further exploration of floral aroma compound biosynthesis pathways in P. mume, and provide new insights into aroma induction and regulation mechanisms in woody plants.
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Affiliation(s)
- Wang Xiujun
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Song Zhenqi
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Ti Yujing
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Ma Kaifeng
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Li Qingwei
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, Beijing, China.
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D'Auria M, Lorenz R, Mecca M, Racioppi R, Romano VA, Viggiani L. Fragrance components of Gymnadenia conopsea and Gymnadenia odoratissima collected at several sites in Italy and Germany. Nat Prod Res 2022; 36:3435-3439. [PMID: 33249883 DOI: 10.1080/14786419.2020.1851227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/01/2020] [Accepted: 11/09/2020] [Indexed: 10/22/2022]
Abstract
The SPME-GC-MS analysis of the aroma components of Gymnadenia conopsea subsp. conopsea, subsp. densiflora, var. alpina and Gymnadenia odoratissima var. odoratissima, var. idae were reported. The main components of in total 78 found in G. conopsea subsp. conopsea were elemicin, cis-9-hexadecenal, hexadecanal, isoelemicin and (Z)-11-hexadecen-1-ol acetate; in subsp. densiflora benzyl benzoate, eugenol and trans-isoeugenol; in var. alpina benzyl benzoate, methyleugenol and elemicin. In the scent of G. odoratissima var. odoratissima were found 2-phenylethyl acetate, eugenol and pentadecane, in var. idae mainly C15-C21 alkanes and C16, C18 carbonic acids and some isoprenoid-derivatives. As all tested Gymnadenia-taxa are allogamous, the differences in scent composition may play a role in pollinator attraction.
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Affiliation(s)
- Maurizio D'Auria
- Dipartimento di Scienze, Università della Basilicata, Potenza, Italy
| | - Richard Lorenz
- Arbeitskreis Heimische Orchideen Baden-Württemberg, Weinheim, Germany
| | - Marisabel Mecca
- Dipartimento di Scienze, Università della Basilicata, Potenza, Italy
| | - Rocco Racioppi
- Dipartimento di Scienze, Università della Basilicata, Potenza, Italy
| | | | - Licia Viggiani
- Dipartimento di Scienze, Università della Basilicata, Potenza, Italy
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Jakubska-Busse A, Czeluśniak I, Kobyłka MJ, Hojniak M. Why does an obligate autogamous orchid produce insect attractants in nectar? - a case study on Epipactis albensis (Orchidaceae). BMC PLANT BIOLOGY 2022; 22:196. [PMID: 35418038 PMCID: PMC9006510 DOI: 10.1186/s12870-022-03563-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 03/28/2022] [Indexed: 05/12/2023]
Abstract
BACKGROUND The flowers of some species of orchids produce nectar as a reward for pollination, the process of transferring pollen from flower to flower. Epipactis albensis is an obligatory autogamous species, does not require the presence of insects for pollination, nevertheless, it has not lost the ability to produce nectar, the chemical composition of which we examined by gas chromatography-mass spectrometry (GC-MS) method for identification of potential insect attractants. RESULTS During five years of field research, we did not observe any true pollinating insects visiting the flowers of this species, only accidental insects as ants and aphids. As a result of our studies, we find that this self-pollinating orchid produces in nectar inter alia aliphatic saturated and unsaturated aldehydes such as nonanal (pelargonal) and 2-pentenal as well as aromatic ones (i.e., syringaldehyde, hyacinthin). The nectar is low in alkenes, which may explain the absence of pollinating insects. Moreover, vanillin and eugenol derivatives, well-known as important scent compounds were also identified, but the list of chemical compounds is much poorer compared with a closely related species, insect-pollinating E. helleborine. CONCLUSION Autogamy is a reproductive mechanism employed by many flowering plants, including the orchid genus Epipactis, as an adaptation to growing in habitats where pollinating insects are rarely observed due to the lack of nectar-producing plants they feed on. The production of numerous chemical attractants by self-pollinated E. albensis confirms the evolutionary secondary process, i.e., transition from ancestral insect-pollinating species to obligatory autogamous.
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Affiliation(s)
- Anna Jakubska-Busse
- University of Wroclaw, Faculty of Biological Sciences, Department of Botany, 50-328, Wroclaw, Poland.
| | | | - Michał J Kobyłka
- University of Wroclaw, Faculty of Chemistry, 50-353, Wroclaw, Poland
| | - Marek Hojniak
- University of Wroclaw, Faculty of Chemistry, 50-353, Wroclaw, Poland
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Bateman RM, Rudall PJ, Denholm I. In situ morphometric survey elucidates the evolutionary systematics of the orchid genus Gymnadenia in the British Isles. SYST BIODIVERS 2021. [DOI: 10.1080/14772000.2021.1877848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Richard M. Bateman
- Jodrell Laboratory, Royal Botanic Gardens Kew, Richmond TW9 3DS, Surrey, UK
| | - Paula J. Rudall
- Jodrell Laboratory, Royal Botanic Gardens Kew, Richmond TW9 3DS, Surrey, UK
| | - Ian Denholm
- Department of Biological and Environmental Sciences, University of Hertfordshire, Hatfield AL10 9AB, Hertfordshire, UK
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Giovannini A, Laura M, Nesi B, Savona M, Cardi T. Genes and genome editing tools for breeding desirable phenotypes in ornamentals. PLANT CELL REPORTS 2021; 40:461-478. [PMID: 33388891 PMCID: PMC7778708 DOI: 10.1007/s00299-020-02632-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 10/27/2020] [Indexed: 05/05/2023]
Abstract
We review the main genes underlying commercial traits in cut flower species and critically discuss the possibility to apply genome editing approaches to produce novel variation and phenotypes. Promoting flowering and flower longevity as well as creating novelty in flower structure, colour range and fragrances are major objectives of ornamental plant breeding. The novel genome editing techniques add new possibilities to study gene function and breed new varieties. The implementation of such techniques, however, relies on detailed information about structure and function of genomes and genes. Moreover, improved protocols for efficient delivery of editing reagents are required. Recent results of the application of genome editing techniques to elite ornamental crops are discussed in this review. Enabling technologies and genomic resources are reviewed in relation to the implementation of such approaches. Availability of the main gene sequences, underlying commercial traits and in vitro transformation protocols are provided for the world's best-selling cut flowers, namely rose, lily, chrysanthemum, lisianthus, tulip, gerbera, freesia, alstroemeria, carnation and hydrangea. Results obtained so far are described and their implications for the improvement of flowering, flower architecture, colour, scent and shelf-life are discussed.
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Affiliation(s)
- A. Giovannini
- CREA Research Centre for Vegetable and Ornamental Crops (CREA OF), Corso degli Inglesi 508, 18038 Sanremo, Italy
| | - M. Laura
- CREA Research Centre for Vegetable and Ornamental Crops (CREA OF), Corso degli Inglesi 508, 18038 Sanremo, Italy
| | - B. Nesi
- CREA Research Centre for Vegetable and Ornamental Crops (CREA OF), Via dei Fiori 8, 51017 Pescia, Italy
| | - M. Savona
- CREA Research Centre for Vegetable and Ornamental Crops (CREA OF), Corso degli Inglesi 508, 18038 Sanremo, Italy
| | - T. Cardi
- CREA Research Centre for Vegetable and Ornamental Crops (CREA OF), Via Cavalleggeri 25, 84098 Pontecagnano Faiano, Italy
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Reddy VA, Li C, Nadimuthu K, Tjhang JG, Jang IC, Rajani S. Sweet Basil Has Distinct Synthases for Eugenol Biosynthesis in Glandular Trichomes and Roots with Different Regulatory Mechanisms. Int J Mol Sci 2021; 22:E681. [PMID: 33445552 PMCID: PMC7826958 DOI: 10.3390/ijms22020681] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/07/2021] [Accepted: 01/09/2021] [Indexed: 11/17/2022] Open
Abstract
Production of a volatile phenylpropene; eugenol in sweet basil is mostly associated with peltate glandular trichomes (PGTs) found aerially. Currently only one eugenol synthase (EGS), ObEGS1 which belongs to PIP family is identified from sweet basil PGTs. Reports of the presence of eugenol in roots led us to analyse other EGSs in roots. We screened for all the PIP family reductase transcripts from the RNA-Seq data. In vivo functional characterization of all the genes in E. coli showed their ability to produce eugenol and were termed as ObEGS2-8. Among all, ObEGS1 displayed highest expression in PGTs and ObEGS4 in roots. Further, eugenol was produced only in the roots of soil-grown plants, but not in roots of aseptically-grown plants. Interestingly, eugenol production could be induced in roots of aseptically-grown plants under elicitation suggesting that eugenol production might occur as a result of environmental cues in roots. The presence of ObEGS4 transcript and protein in aseptically-grown plants indicated towards post-translational modifications (PTMs) of ObEGS4. Bioinformatics analysis showed possibility of phosphorylation in ObEGS4 which was further confirmed by in vitro experiment. Our study reveals the presence of multiple eugenol synthases in sweet basil and provides new insights into their diversity and tissue specific regulation.
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Affiliation(s)
- Vaishnavi Amarr Reddy
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; (V.A.R.); (C.L.); (K.N.); (J.G.T.); (I.-C.J.)
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Chunhong Li
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; (V.A.R.); (C.L.); (K.N.); (J.G.T.); (I.-C.J.)
| | - Kumar Nadimuthu
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; (V.A.R.); (C.L.); (K.N.); (J.G.T.); (I.-C.J.)
| | - Jessica Gambino Tjhang
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; (V.A.R.); (C.L.); (K.N.); (J.G.T.); (I.-C.J.)
| | - In-Cheol Jang
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; (V.A.R.); (C.L.); (K.N.); (J.G.T.); (I.-C.J.)
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Sarojam Rajani
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; (V.A.R.); (C.L.); (K.N.); (J.G.T.); (I.-C.J.)
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Wang Z, Ma H, Zhang M, Wang Z, Tian Y, Li W, Wang Y. Transcriptional response of Asarum heterotropoides Fr. Schmidt var. mandshuricum (Maxim.) Kitag. leaves grown under full and partial daylight conditions. BMC Genomics 2021; 22:16. [PMID: 33407099 PMCID: PMC7788892 DOI: 10.1186/s12864-020-07266-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 11/23/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Asarum heterotropides Fr. Schmidt var. mandshuricum (Maxim.) Kitag. is an important medicinal and industrial plant, which is used in the treatment of various diseases. The main bioactive ingredient is the volatile oil having more than 82 identified components of which methyleugenol, safrole, myristicin, and toluene account for about 70% of the total volume. As a sciophyte plant, the amount of light it absorbs through leaves is an important factor for growth and metabolism. RESULTS We grew Asarum plants under full, 50, 28, and 12% sunlight conditions to investigate the effect of different light irradiances on the four major volatile oil components. We employed de novo transcriptome sequencing to understand the transcriptional behavior of Asarum leaves regarding the biosynthetic pathways of the four volatile oil components, photosynthesis and biomass accumulation, and hormone signaling. Our results demonstrated that the increasing light conditions promoted higher percent of the four components. Under full sunlight conditions, cinnamyl alcohol dehydrogenase and cytochrome p450719As were upregulated and led the increased methyleugenol, safrole, and myristicin. The transcriptomic data also showed that Asarum leaves, under full sunlight conditions, adjust their photosynthesis-antenna proteins as a photoprotective response with the help of carotenoids. Plant hormone-signaling related genes were also differentially expressed between full sunlight and low light conditions. CONCLUSIONS High light induces accumulation of major bioactive ingredients A. heterotropides volatile oil and this is ascribed to upregulation of key genes such as cinnamyl alcohol dehydrogenase and cytochrome p450719As. The transcriptome data presented here lays the foundation of further understanding of light responses in sciophytes and provides guidance for increasing bioactive molecules in Asarum.
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Affiliation(s)
- Zhiqing Wang
- Laboratory of Cultivation and Breeding of Medicinal Plants, National Administration of Traditional Chinese Medicine, College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, Jilin, China.
| | - Haiqin Ma
- Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agriculture Sciences, Changchun, 130112, Jilin, China
| | - Min Zhang
- Laboratory of Cultivation and Breeding of Medicinal Plants, National Administration of Traditional Chinese Medicine, College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, Jilin, China
| | - Ziqing Wang
- Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agriculture Sciences, Changchun, 130112, Jilin, China
| | - Yixin Tian
- Laboratory of Cultivation and Breeding of Medicinal Plants, National Administration of Traditional Chinese Medicine, College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, Jilin, China
| | - Wei Li
- State & Local Joint Engineering Research Center of Ginseng Breeding and Application, College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, Jilin, China
| | - Yingping Wang
- State & Local Joint Engineering Research Center of Ginseng Breeding and Application, College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, Jilin, China
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Ramya M, Jang S, An HR, Lee SY, Park PM, Park PH. Volatile Organic Compounds from Orchids: From Synthesis and Function to Gene Regulation. Int J Mol Sci 2020; 21:ijms21031160. [PMID: 32050562 PMCID: PMC7037033 DOI: 10.3390/ijms21031160] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/04/2020] [Accepted: 02/07/2020] [Indexed: 01/26/2023] Open
Abstract
Orchids are one of the most significant plants that have ecologically adapted to every habitat on earth. Orchids show a high level of variation in their floral morphologies, which makes them popular as ornamental plants in the global market. Floral scent and color are key traits for many floricultural crops. Volatile organic compounds (VOCs) play vital roles in pollinator attraction, defense, and interaction with the environment. Recent progress in omics technology has led to the isolation of genes encoding candidate enzymes responsible for the biosynthesis and regulatory circuits of plant VOCs. Uncovering the biosynthetic pathways and regulatory mechanisms underlying the production of floral scents is necessary not only for a better understanding of the function of relevant genes but also for the generation of new cultivars with desirable traits through molecular breeding approaches. However, little is known about the pathways responsible for floral scents in orchids because of their long life cycle as well as the complex and large genome; only partial terpenoid pathways have been reported in orchids. Here, we review the biosynthesis and regulation of floral volatile compounds in orchids. In particular, we focused on the genes responsible for volatile compounds in various tissues and developmental stages in Cymbidium orchids. We also described the emission of orchid floral volatiles and their function in pollination ecology. Taken together, this review will provide a broad scope for the study of orchid floral scents.
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Affiliation(s)
- Mummadireddy Ramya
- Floriculture Research Division, National Institute of Horticultural and Herbal Science, RDA, Wanju-gun, Jellabuk-do 55365, Korea; (M.R.); (H.-R.A.); (S.-Y.L.); (P.-M.P.)
| | - Seonghoe Jang
- World Vegetable Center Korea Office (WKO), Wanju-gun, Jellabuk-do 55365, Korea;
| | - Hye-Ryun An
- Floriculture Research Division, National Institute of Horticultural and Herbal Science, RDA, Wanju-gun, Jellabuk-do 55365, Korea; (M.R.); (H.-R.A.); (S.-Y.L.); (P.-M.P.)
| | - Su-Young Lee
- Floriculture Research Division, National Institute of Horticultural and Herbal Science, RDA, Wanju-gun, Jellabuk-do 55365, Korea; (M.R.); (H.-R.A.); (S.-Y.L.); (P.-M.P.)
| | - Pil-Man Park
- Floriculture Research Division, National Institute of Horticultural and Herbal Science, RDA, Wanju-gun, Jellabuk-do 55365, Korea; (M.R.); (H.-R.A.); (S.-Y.L.); (P.-M.P.)
| | - Pue Hee Park
- Floriculture Research Division, National Institute of Horticultural and Herbal Science, RDA, Wanju-gun, Jellabuk-do 55365, Korea; (M.R.); (H.-R.A.); (S.-Y.L.); (P.-M.P.)
- Department of Horticultural Science and Biotechnology, Seoul National University (SNU), Seoul 08826, Korea
- Correspondence: or ; Tel.: +82-10-4507-8321 or +82-63-238-6842; Fax: +82-63-238-6805
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Zhang T, Huo T, Ding A, Hao R, Wang J, Cheng T, Bao F, Zhang Q. Genome-wide identification, characterization, expression and enzyme activity analysis of coniferyl alcohol acetyltransferase genes involved in eugenol biosynthesis in Prunus mume. PLoS One 2019; 14:e0223974. [PMID: 31618262 PMCID: PMC6795479 DOI: 10.1371/journal.pone.0223974] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/02/2019] [Indexed: 12/12/2022] Open
Abstract
Prunus mume, a traditional Chinese flower, is the only species of Prunus known to produce a strong floral fragrance, of which eugenol is one of the principal components. To explore the molecular mechanism of eugenol biosynthesis in P. mume, patterns of dynamic, spatial and temporal variation in eugenol were analysed using GC-MS. Coniferyl alcohol acetyltransferase (CFAT), a member of the BAHD acyltransferase family, catalyses the substrate of coniferyl alcohol to coniferyl acetate, which is an important substrate for synthesizing eugenol. In a genome-wide analysis, we found 90 PmBAHD genes that were phylogenetically clustered into five major groups with motif compositions relatively conserved in each cluster. The phylogenetic tree showed that the PmBAHD67-70 proteins were close to the functional CFATs identified in other species, indicating that these four proteins might function as CFATs. In this work, 2 PmCFAT genes, named PmCFAT1 and PmCFAT2, were cloned from P. mume ‘Sanlunyudie’, which has a strong fragrance. Multiple sequences indicated that PmCFAT1 contained two conserved domains, HxxxD and DFGWG, whereas DFGWG in PmCFAT2 was changed to DFGFG. The expression levels of PmCFAT1 and PmCFAT2 were examined in different flower organs and during the flowering stages of P. mume ‘Sanlunyudie’. The results showed that PmCFAT1 was highly expressed in petals and stamens, and this expression increased from the budding stage to the full bloom stage and decreased in the withering stage, consistent with the patterns of eugenol synthesis and emission. However, the peak of gene expression appeared earlier than those of eugenol synthesis and emission. In addition, the expression level of PmCFAT2 was higher in pistils and sepals than in other organs and decreased from the budding stage to the blooming stage and then increased in the withering stage, which was not consistent with eugenol synthesis. Subcellular localization analysis indicated that PmCFAT1 and PmCFAT2 were located in the cytoplasm and nucleus, while enzyme activity assays showed that PmCFAT1 is involved in eugenol biosynthesis in vitro. Overall, the results suggested that PmCFAT1, but not PmCFAT2, contributed to eugenol synthesis in P. mume.
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Affiliation(s)
- Tengxun Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, Beijing Forestry University, Beijing, China
- National Engineering Research Center for Floriculture, Beijing Forestry University, Beijing, China
- Beijing Laboratory of Urban and Rural Ecological Environment, Beijing Forestry University, Beijing, China
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Beijing Forestry University, Beijing, China
- School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Tingting Huo
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, Beijing Forestry University, Beijing, China
- National Engineering Research Center for Floriculture, Beijing Forestry University, Beijing, China
- Beijing Laboratory of Urban and Rural Ecological Environment, Beijing Forestry University, Beijing, China
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Beijing Forestry University, Beijing, China
- School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Anqi Ding
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, Beijing Forestry University, Beijing, China
- National Engineering Research Center for Floriculture, Beijing Forestry University, Beijing, China
- Beijing Laboratory of Urban and Rural Ecological Environment, Beijing Forestry University, Beijing, China
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Beijing Forestry University, Beijing, China
- School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Ruijie Hao
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, Beijing Forestry University, Beijing, China
- National Engineering Research Center for Floriculture, Beijing Forestry University, Beijing, China
- Beijing Laboratory of Urban and Rural Ecological Environment, Beijing Forestry University, Beijing, China
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Beijing Forestry University, Beijing, China
- School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Jia Wang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, Beijing Forestry University, Beijing, China
- National Engineering Research Center for Floriculture, Beijing Forestry University, Beijing, China
- Beijing Laboratory of Urban and Rural Ecological Environment, Beijing Forestry University, Beijing, China
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Beijing Forestry University, Beijing, China
| | - Tangren Cheng
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, Beijing Forestry University, Beijing, China
- National Engineering Research Center for Floriculture, Beijing Forestry University, Beijing, China
- Beijing Laboratory of Urban and Rural Ecological Environment, Beijing Forestry University, Beijing, China
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Beijing Forestry University, Beijing, China
| | - Fei Bao
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, Beijing Forestry University, Beijing, China
- National Engineering Research Center for Floriculture, Beijing Forestry University, Beijing, China
- Beijing Laboratory of Urban and Rural Ecological Environment, Beijing Forestry University, Beijing, China
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Beijing Forestry University, Beijing, China
- * E-mail: (FB); (QZ)
| | - Qixiang Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, Beijing Forestry University, Beijing, China
- National Engineering Research Center for Floriculture, Beijing Forestry University, Beijing, China
- Beijing Laboratory of Urban and Rural Ecological Environment, Beijing Forestry University, Beijing, China
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Beijing Forestry University, Beijing, China
- School of Landscape Architecture, Beijing Forestry University, Beijing, China
- * E-mail: (FB); (QZ)
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12
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Wong DCJ, Amarasinghe R, Falara V, Pichersky E, Peakall R. Duplication and selection in β-ketoacyl-ACP synthase gene lineages in the sexually deceptive Chiloglottis (Orchidaceace). ANNALS OF BOTANY 2019; 123:1053-1066. [PMID: 30789664 PMCID: PMC6589519 DOI: 10.1093/aob/mcz013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 02/05/2019] [Indexed: 05/17/2023]
Abstract
BACKGROUND AND AIMS The processes of gene duplication, followed by divergence and selection, probably underpin the evolution of floral volatiles crucial to plant-insect interactions. The Australian sexually deceptive Chiloglottis orchids use a class of 2,5-dialkylcyclohexan-1,3-dione volatiles or 'chiloglottones' to attract specific male wasp pollinators. Here, we explore the expression and evolution of fatty acid pathway genes implicated in chiloglottone biosynthesis. METHODS Both Chiloglottis seminuda and C. trapeziformis produce chiloglottone 1, but only the phylogenetically distinct C. seminuda produces this volatile from both the labellum callus and glandular sepal tips. Transcriptome sequencing and tissue-specific contrasts of the active and non-active floral tissues was performed. The effects of the fatty acid synthase inhibitor cerulenin on chiloglottone production were tested. Patterns of selection and gene evolution were investigated for fatty acid pathway genes. KEY RESULTS Tissue-specific differential expression of fatty acid pathway transcripts was evident between active and non-active floral tissues. Cerulenin significantly inhibits chiloglottone 1 production in the active tissues of C. seminuda. Phylogenetic analysis of plant β-ketoacyl synthase I (KASI), a protein involved in fatty acid biosynthesis, revealed two distinct clades, one of which is unique to the Orchidaceae (KASI-2B). Selection analysis indicated a strong signal of positive selection at the split of KASI-2B followed by relaxed purifying selection in the Chiloglottis clade. CONCLUSIONS By capitalizing on a phylogenetically distinct Chiloglottis from earlier studies, we show that the transcriptional and biochemical dynamics linked to chiloglottone biosynthesis in active tissues are conserved across Chiloglottis. A combination of tissue-specific expression and relaxed purifying selection operating at specific fatty acid pathway genes may hold the key to the evolution of chiloglottones.
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Affiliation(s)
- Darren C J Wong
- Ecology and Evolution, Research School of Biology, The Australian National University, Acton, Australia
- For correspondence. E-mail ,
| | - Ranamalie Amarasinghe
- Ecology and Evolution, Research School of Biology, The Australian National University, Acton, Australia
| | - Vasiliki Falara
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Eran Pichersky
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Rod Peakall
- Ecology and Evolution, Research School of Biology, The Australian National University, Acton, Australia
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13
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Yahyaa M, Berim A, Nawade B, Ibdah M, Dudareva N, Ibdah M. Biosynthesis of methyleugenol and methylisoeugenol in Daucus carota leaves: Characterization of eugenol/isoeugenol synthase and O-Methyltransferase. PHYTOCHEMISTRY 2019; 159:179-189. [PMID: 30634080 DOI: 10.1016/j.phytochem.2018.12.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 12/25/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
Carrot (Daucus carota subsp. sativus) is a widely cultivated root vegetable of high economic importance. The aroma of carrot roots and aboveground organs is mainly defined by terpenes. We found that leaves of orange carrot cultivar also produce considerable amounts of the phenylpropenes methyleugenol and methylisoeugenol. Notably, methyleugenol is most abundant in young leaves, while methylisoeugenol is the dominant phenylpropene in mature leaf tissue. The goal of the present study was to shed light on the biochemistry and molecular biology of these compounds' biosynthesis and accumulation. Using the available genomic and transcriptomic data, we isolated a cDNA encoding eugenol/isoeugenol synthase (DcE(I)GS1), an NADPH-dependent enzyme that converts coniferyl acetate to eugenol. This enzyme exhibits dual product specificity and yields propenylphenol isoeugenol alongside allylphenol eugenol. Furthermore, we identified a cDNA encoding S-adenosyl-L-methionine:eugenol/isoeugenol O-methyltransferase 1 (DcE(I)OMT1) that produces methyleugenol and methylisoeugenol via methylation of the para-OH-group of their respective precursors. Both DcE(I)GS1 and DcE(I)OMT1 were expressed in seeds, roots, young and mature leaves, and the DcE(I)OMT1 transcript levels were the highest in leaves. The DcE(I)GS1 protein is 67% identical to anise t-anol/isoeugenol synthase and displays an apparent Km of 247 μM for coniferyl acetate. The catalytic efficiency of DcEOMT1 with eugenol is more than five-fold higher than that with isoeugenol, with Km values of 40 μM for eugenol, and of 115 μM for isoeugenol. This work expands the current knowledge of the enzymes involved in phenylpropene biosynthesis and would enable studies into structural elements defining the regioselectivity of phenylpropene synthases.
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Affiliation(s)
- Mosaab Yahyaa
- Newe Yaar Research Center, Agricultural Research Organization, P. O. Box 1021, Ramat Yishay, 30095, Israel
| | - Anna Berim
- Institute of Biological Chemistry, Washington State University, P. O. Box 646340, Pullman, WA 99164-6340, USA
| | - Bhagwat Nawade
- Newe Yaar Research Center, Agricultural Research Organization, P. O. Box 1021, Ramat Yishay, 30095, Israel
| | - Muhammad Ibdah
- Sakhnin College Academic College for Teacher Education, Sakhnin, Israel
| | - Natalia Dudareva
- Purdue University, Department of Biochemistry, 175 S. University Street, West Lafayette, IN 47907-2063, USA
| | - Mwafaq Ibdah
- Newe Yaar Research Center, Agricultural Research Organization, P. O. Box 1021, Ramat Yishay, 30095, Israel.
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14
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Liu J, Xu C, Zhang H, Liu F, Ma D, Liu Z. Comparative Transcriptomics Analysis for Gene Mining and Identification of a Cinnamyl Alcohol Dehydrogenase Involved in Methyleugenol Biosynthesis from Asarum sieboldii Miq. Molecules 2018; 23:E3184. [PMID: 30513938 PMCID: PMC6321292 DOI: 10.3390/molecules23123184] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 11/29/2018] [Accepted: 12/01/2018] [Indexed: 01/09/2023] Open
Abstract
Asarum sieboldii Miq., one of the three original plants of TCM ASARI RADIX ET RHIZOMA, is a perennial herb distributed in central and eastern China, the Korean Peninsula, and Japan. Methyleugenol has been considered as the most important constituent of Asarum volatile oil, meanwhile asarinin is also employed as the quality control standard of ASARI RADIX ET RHIZOMA in Chinese Pharmacopeia. They both have shown wide range of biological activities. However, little was known about genes involved in biosynthesis pathways of either methyleugenol or asarinin in Asarum plants. In the present study, we performed de novo transcriptome analysis of plant tissues (e.g., roots, rhizomes, and leaves) at different developmental stages. The sequence assembly resulted in 311,597 transcripts from these plant materials, among which 925 transcripts participated in 'secondary metabolism' with particularly up to 20.22% of them falling into phenylpropanoid biosynthesis pathway. The corresponding enzymes belong to seven families potentially encoding phenylalanine ammonia-lyase (PAL), trans-cinnamate 4-monooxygenase (C4H), p-coumarate 3-hydroxylase (C3H), caffeoyl-CoA O-methyltransferase (CCoAOMT), cinnamoyl-CoA reductase (CCR), cinnamyl alcohol dehydrogenase (CAD), and eugenol synthase (EGS). Moreover, 5 unigenes of DIR (dirigent protein) and 11 unigenes of CYP719A (719A subfamily of cytochrome P450 oxygenases) were speculated to be involved in asarinin pathway. Of the 15 candidate CADs, four unigenes that possessed high FPKM (fragments per transcript kilobase per million fragments mapped) value in roots were cloned and characterized. Only the recombinant AsCAD5 protein efficiently converted p-coumaryl, coniferyl, and sinapyl aldehydes to their corresponding alcohols, which are key intermediates employed not only in biosynthesis of lignin but also in that of methyleugenol and asarinin. qRT-PCR revealed that AsCAD5 had a high expression level in roots at three developmental stages. Our study will provide insight into the potential application of molecular breeding and metabolic engineering for improving the quality of TCM ASARI RADIX ET RHIZOMA.
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Affiliation(s)
- Jinjie Liu
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Chong Xu
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Honglei Zhang
- Jiusan administration of Heilongjiang farms & land reclamation, Harbin 161441, China.
| | - Fawang Liu
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Dongming Ma
- Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Zhong Liu
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.
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15
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Koeduka T. Functional evolution of biosynthetic enzymes that produce plant volatiles. Biosci Biotechnol Biochem 2018; 82:192-199. [PMID: 29338642 DOI: 10.1080/09168451.2017.1422968] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Plants synthesize volatile compounds to attract pollinators. The volatiles emitted by flowers are often complex mixtures of organic compounds; pollinators are capable of distinctly recognizing different volatile compounds. Plants also produce volatile compounds to protect themselves against herbivores and pathogens. Some of the volatile compounds produced in floral and vegetative tissues are toxic to insects and microbes. To adapt changes in the environment, plants have evolved the ability to synthesize a unique set of volatiles. Intensive studies have identified and characterized the enzymes responsible for the formation of plant volatiles. In particular, many biosynthetic genes have been isolated and their enzymatic functions have been proposed. This review describes how plants have evolved the biosynthetic pathways leading to the formation of green leaf volatiles and phenylpropene volatiles.
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Affiliation(s)
- Takao Koeduka
- a Graduate School of Sciences and Technology for Innovation (Agriculture), Department of Biological Chemistry , Yamaguchi University , Yamaguchi , Japan
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16
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Palmer-Young EC, Sadd BM, Irwin RE, Adler LS. Synergistic effects of floral phytochemicals against a bumble bee parasite. Ecol Evol 2017; 7:1836-1849. [PMID: 28331591 PMCID: PMC5355193 DOI: 10.1002/ece3.2794] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 01/02/2017] [Accepted: 01/14/2017] [Indexed: 12/24/2022] Open
Abstract
Floral landscapes comprise diverse phytochemical combinations. Individual phytochemicals in floral nectar and pollen can reduce infection in bees and directly inhibit trypanosome parasites. However, gut parasites of generalist pollinators, which consume nectar and pollen from many plant species, are exposed to phytochemical combinations. Interactions between phytochemicals could augment or decrease effects of single compounds on parasites. Using a matrix of 36 phytochemical treatment combinations, we assessed the combined effects of two floral phytochemicals, eugenol and thymol, against four strains of the bumblebee gut trypanosome Crithidia bombi. Eugenol and thymol had synergistic effects against C. bombi growth across seven independent experiments, showing that the phytochemical combination can disproportionately inhibit parasites. The strength of synergistic effects varied across strains and experiments. Thus, the antiparasitic effects of individual compounds will depend on both the presence of other phytochemicals and parasite strain identity. The presence of synergistic phytochemical combinations could augment the antiparasitic activity of individual compounds for pollinators in diverse floral landscapes.
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Affiliation(s)
| | - Ben M Sadd
- School of Biological Sciences Illinois State University Normal IL USA
| | - Rebecca E Irwin
- Department of Applied Ecology North Carolina State University Raleigh NC USA
| | - Lynn S Adler
- Department of Biology University of Massachusetts at Amherst Amherst MA USA
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17
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Palmer‐Young EC, Sadd BM, Adler LS. Evolution of resistance to single and combined floral phytochemicals by a bumble bee parasite. J Evol Biol 2017; 30:300-312. [PMID: 27783434 PMCID: PMC5324628 DOI: 10.1111/jeb.13002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 01/05/2023]
Abstract
Repeated exposure to inhibitory compounds can drive the evolution of resistance, which weakens chemical defence against antagonists. Floral phytochemicals in nectar and pollen have antimicrobial properties that can ameliorate infection in pollinators, but evolved resistance among parasites could diminish the medicinal efficacy of phytochemicals. However, multicompound blends, which occur in nectar and pollen, present simultaneous chemical challenges that may slow resistance evolution. We assessed evolution of resistance by the common bumble bee gut parasite Crithidia bombi to two floral phytochemicals, singly and combined, over 6 weeks (~100 generations) of chronic exposure. Resistance of C. bombi increased under single and combined phytochemical exposure, without any associated costs of reduced growth under phytochemical-free conditions. After 6 weeks' exposure, phytochemical concentrations that initially inhibited growth by > 50%, and exceeded concentrations in floral nectar, had minimal effects on evolved parasite lines. Unexpectedly, the phytochemical combination did not impede resistance evolution compared to single compounds. These results demonstrate that repeated phytochemical exposure, which could occur in homogeneous floral landscapes or with therapeutic phytochemical treatment of managed hives, can cause rapid evolution of resistance in pollinator parasites. We discuss possible explanations for submaximal phytochemical resistance in natural populations. Evolved resistance could diminish the antiparasitic value of phytochemical ingestion, weakening an important natural defence against infection.
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Affiliation(s)
| | - B. M. Sadd
- School of Biological SciencesIllinois State UniversityNormalILUSA
| | - L. S. Adler
- Department of BiologyUniversity of Massachusetts at AmherstAmherstMAUSA
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18
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Cai J, Zu P, Schiestl FP. The molecular bases of floral scent evolution under artificial selection: insights from a transcriptome analysis in Brassica rapa. Sci Rep 2016; 6:36966. [PMID: 27841366 PMCID: PMC5107913 DOI: 10.1038/srep36966] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/13/2016] [Indexed: 12/24/2022] Open
Abstract
In an artificial selection experiment using fast-cycling Brassica rapa plants it was recently shown that floral VOCs respond rapidly to selection for increased amounts. Here we carried out transcriptome analysis in these plants to explore the molecular bases of the augmentation in the artificially selected scent compound, phenylacetaldehyde (PAA), as well as other compounds that increased through pleiotropy. In the transcriptome data, we found up-regulation of genes likely underlying PAA synthesis, but also several genes of the shikimate pathway and the related phenylalanine metabolism. As phenylalanine is the precursor of many aromatic volatiles that showed increased emission, this result could explain some of the pleiotropic evolutionary responses. In addition, we found that ribosomal protein genes were up-regulated in “high” (high PAA amount) selection line plants, a mechanism that might further augment the effect of elevated gene expression at the proteomic level. Our study shows that selection on an individual trait can impose changes in the expression of several different genes, which could explain pleiotropic responses in the biosynthetic network of floral volatiles.
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Affiliation(s)
- Jing Cai
- Department of Systematic and Evolutionary Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
| | - Pengjuan Zu
- Department of Systematic and Evolutionary Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
| | - Florian P Schiestl
- Department of Systematic and Evolutionary Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
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19
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Parachnowitsch AL, Manson JS. The chemical ecology of plant-pollinator interactions: recent advances and future directions. CURRENT OPINION IN INSECT SCIENCE 2015; 8:41-46. [PMID: 32846674 DOI: 10.1016/j.cois.2015.02.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/31/2015] [Accepted: 02/04/2015] [Indexed: 05/24/2023]
Abstract
Floral chemistry mediates plant-pollinator interactions through floral scents and reward components. Although improved techniques have increased interest in studying floral volatiles and nectar chemistry, these two foci have generally been studied in isolation. The ecological functions of floral chemistry have been relatively well studied and focused on pollinator behaviour. While studies comparing chemistry between plant parts and across phylogenies are increasing, work on the evolution of floral chemistry and the importance of community context in mediating pollinator responses is lacking. Future research should concentrate on more holistic studies that include both signal and reward chemistry to understand the relative contribution of these complex and dynamic floral traits to the ecology and evolution of plants and their pollinators.
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Affiliation(s)
- Amy L Parachnowitsch
- Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden.
| | - Jessamyn S Manson
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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