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Kato-Noguchi H. Allelopathy and Allelochemicals of Imperata cylindrica as an Invasive Plant Species. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11192551. [PMID: 36235415 PMCID: PMC9573136 DOI: 10.3390/plants11192551] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 05/17/2023]
Abstract
Imperata cylindrica is native to Southeast Asia and East Africa and has become naturalized in humid tropics, subtropics and warmer temperate zones of the world. The species is one of the top ten worst weeds in the worlds and is listed among the world's top 100 worst invasive alien species. It is an aggressive colonizer and forms large monospecific stands in several countries. Possible evidence of the allelopathy of I. cylindrica has been accumulated in the literature over three decades. The extracts, leachates, root exudates, decomposing residues and rhizosphere soil of I. cylindrica were found to suppress the germination and growth of several plant species, including woody plant species, and to reduce their rhizobium nodulation and mycorrhizal colonization. Several allelochemicals, such as fatty acids, terpenoids, simple phenolics, benzoic acids, phenolic acids, phenolic aldehydes, phenylpropanoids, flavonoids, quinones and alkaloids, were also found in the extracts, leachates, root exudates and/or growth medium of I. cylindrica. These observations suggest that allelochemicals may be synthesized in I. cylindrica and released into the rhizosphere soil and surrounding environments either by the leachates, root exudation or decomposition process of plant parts, and certain allelochemicals may contribute to the alteration of the microbial community, including rhizobia and mycorrhizal fungi, suppressing the regeneration process of native plant species through the inhibition of their germination and growth. Therefore, the allelopathy of I. cylindrica may support its invasiveness, naturalization and formation of large monospecific stands. This is the first review article focusing on the allelopathy of I. cylindrica.
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Affiliation(s)
- Hisashi Kato-Noguchi
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki 761-0795, Kagawa, Japan
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Kato-Noguchi H, Kurniadie D. Allelopathy and Allelochemicals of Leucaenaleucocephala as an Invasive Plant Species. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11131672. [PMID: 35807624 PMCID: PMC9269122 DOI: 10.3390/plants11131672] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 05/30/2023]
Abstract
Leucaena leucocephala (Lam.) de Wit is native to southern Mexico and Central America and is now naturalized in more than 130 countries. The spread of L. leucocephala is probably due to its multipurpose use such as fodder, timber, paper pulp, shade trees, and soil amendment. However, the species is listed in the world's 100 worst invasive alien species, and an aggressive colonizer. It forms dense monospecific stands and threatens native plant communities, especially in oceanic islands. Phytotoxic chemical interactions such as allelopathy have been reported to play an important role in the invasion of several invasive plant species. Possible evidence for allelopathy of L. leucocephala has also been accumulated in the literature over 30 years. The extracts, leachates, root exudates, litter, decomposing residues, and rhizosphere soil of L. leucocephala increased the mortality and suppressed the germination and growth of several plant species, including weeds and woody plants. Those observations suggest that L. leucocephala is allelopathic and contains certain allelochemicals. Those allelochemicals may release into the rhizosphere soil during decomposition process of the plant residues and root exudation. Several putative allelochemicals such as phenolic acids, flavonoids, and mimosine were identified in L. leucocephala. The species produces a large amount of mimosine and accumulates it in almost all parts of the plants, including leaves, stems, seeds, flowers, roots, and root nodules. The concentrations of mimosine in these parts were 0.11 to 6.4% of their dry weight. Mimosine showed growth inhibitory activity against several plant species, including some woody plants and invasive plants. Mimosine blocked cell division of protoplasts from Petunia hybrida hort. ex E. Vilm. between G1 and S phases, and disturbed the enzyme activity such as peroxidase, catalase, and IAA oxidase. Some of those identified compounds in L. leucocephala may be involved in its allelopathy. Therefore, the allelopathic property of L. leucocephala may support its invasive potential and formation of dense monospecific stands. However, the concentrations of mimosine, phenolic acids, and flavonoids in the vicinity of L. leucocephala, including its rhizosphere soil, have not yet been reported.
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Affiliation(s)
- Hisashi Kato-Noguchi
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki 761-0795, Japan
| | - Denny Kurniadie
- Department of Agronomy, Faculty of Agriculture, Universitas Padjadjaran, Jl. Raya, Bandung Sumedang Km 21, Jatinangor, Sumedang 45363, Indonesia;
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LC–DAD–MS Phenolic Characterisation of Six Invasive Plant Species in Croatia and Determination of Their Antimicrobial and Cytotoxic Activity. PLANTS 2022; 11:plants11050596. [PMID: 35270066 PMCID: PMC8912889 DOI: 10.3390/plants11050596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/04/2022] [Accepted: 02/19/2022] [Indexed: 12/03/2022]
Abstract
Invasive plants’ phytochemicals are important for their invasiveness, enabling them to spread in new environments. However, these chemicals could offer many pharmaceutical compounds or active ingredients for herbal preparations. This study provides the first LC–MS phytochemical screening of six invasive alien plant species (IAPS) in the Istria region (Croatia): Ailanthus altissima, Ambrosia artemisiifolia, Conyza canadensis, Dittrichia viscosa, Erigeron annuus, and Xanthium strumarium. The study aims to identify and quantify the phenolic content of their leaf extracts and assess their antimicrobial and cytotoxic potential. A total of 32 species-specific compounds were recorded. Neochlorogenic, chlorogenic, and 5-p-coumaroylquinic acids, quercetin-3-glucoside, and kaempferol hexoside were detected in all the tested IAPS. Hydroxycinnamic acid derivatives were the main components in all the tested IAPS, except in E. annuus, where flavanones dominated with a share of 70%. X. strumarium extract had the best activity against the tested bacteria, with an average MIC value of 0.11 mg/mL, while A. altissima and X. strumarium extracts had the best activity against the tested fungi, with an average MIC value of 0.21 mg/mL in both cases. All the plant extracts studied, except X. strumarium, were less cytotoxic than the positive control. The results provided additional information on the phytochemical properties of IAPS and their potential for use as antimicrobial agents.
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Kato-Noguchi H. Allelopathy of Knotweeds as Invasive Plants. PLANTS (BASEL, SWITZERLAND) 2021; 11:3. [PMID: 35009007 PMCID: PMC8747059 DOI: 10.3390/plants11010003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/17/2021] [Accepted: 12/17/2021] [Indexed: 11/16/2022]
Abstract
Perennial herbaceous Fallopia is native to East Asia, and was introduced to Europe and North America in the 19th century as an ornamental plant. Fallopia has been spreading quickly and has naturalized in many countries. It is listed in the world's 100 worst alien species. Fallopia often forms dense monospecies stands through the interruption of the regeneration process of indigenous plant species. Allelopathy of Japanese knotweed (Fallopia japonica), giant knotweed (Fallopia sachalinensis), and Bohemian knotweed (Fallopia x bohemica) has been reported to play an essential role in its invasion. The exudate from their roots and/or rhizomes, and their plant residues inhibited the germination and growth of some other plant species. These knotweeds, which are non-mycorrhizal plants, also suppressed the abundance and species richness of arbuscular mycorrhizal fungi (AMF) in the rhizosphere soil. Such suppression was critical for most territorial plants to form the mutualism with AMF, which enhances the nutrient and water uptake, and the tolerance against pathogens and stress conditions. Several allelochemicals such as flavanols, stilbenes, and quinones were identified in the extracts, residues, and rhizosphere soil of the knotweeds. The accumulated evidence suggests that some of those allelochemicals in knotweeds may be released into the rhizosphere soil through the decomposition process of their plant parts, and the exudation from their rhizomes and roots. Those allelochemicals may inhibit the germination and growth of native plants, and suppress the mycorrhizal colonization of native plants, which provides the knotweeds with a competitive advantage, and interrupts the regeneration processes of native plants. Therefore, allelopathy of knotweeds may contribute to establishing their new habitats in the introduced ranges as invasive plant species. It is the first review article focusing on the allelopathy of knotweeds.
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Affiliation(s)
- Hisashi Kato-Noguchi
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki 761-0795, Kagawa, Japan
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Staszek P, Krasuska U, Ciacka K, Gniazdowska A. ROS Metabolism Perturbation as an Element of Mode of Action of Allelochemicals. Antioxidants (Basel) 2021; 10:antiox10111648. [PMID: 34829519 PMCID: PMC8614981 DOI: 10.3390/antiox10111648] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/10/2021] [Accepted: 10/18/2021] [Indexed: 11/16/2022] Open
Abstract
The allelopathic interaction between plants is one of the elements that influences plant communities. It has been commonly studied by applying tissue extracts onto the acceptors or by treating them with isolated allelotoxins. Despite descriptive observations useful for agricultural practice, data describing the molecular mode of action of allelotoxins cannot be found. Due to the development of -omic techniques, we have an opportunity to investigate specific reactive oxygen species (ROS)-dependent changes in proteome or transcriptome that are induced by allelochemicals. The aim of our review is to summarize data on the ROS-induced modification in acceptor plants in response to allelopathic plants or isolated allelochemicals. We present the idea of how ROS are involved in the hormesis and plant autotoxicity phenomena. As an example of an -omic approach in studies of the mode of action of allelopatic compounds, we describe the influence of meta-tyrosine, an allelochemical exudated from roots of fescues, on nitration-one of nitro-oxidative posttranslational protein modification in the roots of tomato plants. We conclude that ROS overproduction and an induction of oxidative stress are general plants' responses to various allelochemicals, thus modification in ROS metabolisms is regarded as an indirect mode of action of allelochemicals.
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Souto AL, Sylvestre M, Tölke ED, Tavares JF, Barbosa-Filho JM, Cebrián-Torrejón G. Plant-Derived Pesticides as an Alternative to Pest Management and Sustainable Agricultural Production: Prospects, Applications and Challenges. Molecules 2021; 26:4835. [PMID: 34443421 PMCID: PMC8400533 DOI: 10.3390/molecules26164835] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/31/2021] [Accepted: 08/04/2021] [Indexed: 11/24/2022] Open
Abstract
Pests and diseases are responsible for most of the losses related to agricultural crops, either in the field or in storage. Moreover, due to indiscriminate use of synthetic pesticides over the years, several issues have come along, such as pest resistance and contamination of important planet sources, such as water, air and soil. Therefore, in order to improve efficiency of crop production and reduce food crisis in a sustainable manner, while preserving consumer's health, plant-derived pesticides may be a green alternative to synthetic ones. They are cheap, biodegradable, ecofriendly and act by several mechanisms of action in a more specific way, suggesting that they are less of a hazard to humans and the environment. Natural plant products with bioactivity toward insects include several classes of molecules, for example: terpenes, flavonoids, alkaloids, polyphenols, cyanogenic glucosides, quinones, amides, aldehydes, thiophenes, amino acids, saccharides and polyketides (which is not an exhaustive list of insecticidal substances). In general, those compounds have important ecological activities in nature, such as: antifeedant, attractant, nematicide, fungicide, repellent, insecticide, insect growth regulator and allelopathic agents, acting as a promising source for novel pest control agents or biopesticides. However, several factors appear to limit their commercialization. In this critical review, a compilation of plant-derived metabolites, along with their corresponding toxicology and mechanisms of action, will be approached, as well as the different strategies developed in order to meet the required commercial standards through more efficient methods.
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Affiliation(s)
- Augusto Lopes Souto
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Universidade Federal da Paraíba, João Pessoa 58051-900, Brazil; (A.L.S.); (J.F.T.); (J.M.B.-F.)
| | - Muriel Sylvestre
- COVACHIM-M2E Laboratory EA 3592, Department of Chemistry, Fouillole Campus, University of the French West Indies, UFR Sciences Exactes et Naturelles, CEDEX, 97157 Pointe-à-Pitre, France;
| | - Elisabeth Dantas Tölke
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, Brazil;
| | - Josean Fechine Tavares
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Universidade Federal da Paraíba, João Pessoa 58051-900, Brazil; (A.L.S.); (J.F.T.); (J.M.B.-F.)
| | - José Maria Barbosa-Filho
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Universidade Federal da Paraíba, João Pessoa 58051-900, Brazil; (A.L.S.); (J.F.T.); (J.M.B.-F.)
| | - Gerardo Cebrián-Torrejón
- COVACHIM-M2E Laboratory EA 3592, Department of Chemistry, Fouillole Campus, University of the French West Indies, UFR Sciences Exactes et Naturelles, CEDEX, 97157 Pointe-à-Pitre, France;
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Hussain MI, El-Sheikh MA, Reigosa MJ. Allelopathic Potential of Aqueous Extract from Acacia melanoxylon R. Br. on Lactuca sativa. PLANTS 2020; 9:plants9091228. [PMID: 32961867 PMCID: PMC7570383 DOI: 10.3390/plants9091228] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/13/2020] [Accepted: 09/14/2020] [Indexed: 12/28/2022]
Abstract
We studied the polyphenol (phenolic compounds and flavonoids) composition and allelopathic effects of Acacia melanoxylon R. Br. aerial foliage aqueous extract (0%, 25%, 50%, 75% and 100%) on the seedling growth and plant biomass of the general biotest species, lettuce (Lactuca sativa). Mean leaf fresh weight, leaf dry weight, root fresh weight and root dry weight were decreased following exposure to Acacia aerial foliage, flowers aqueous extract (AFE) and phyllodes aqueous extract (APE) after 6 days. The reduction in plant dry biomass was more than 50% following treatment with AFE. The decrease in mean root length was approximately 37.7% and 29.20% following treatment with Acacia flowers extract (AFE) at 75% and 100% concentration, respectively. Root dry weight of L. sativa was reduced by both flowers and phyllodes extract. The reduction of protein contents in lettuce leaves following Acacia foliage extract proved that both AFE and APE exhibit polyphenols that causes the toxicity which led to decrease in leaf protein contents. High-Performance Liquid Chromatography (HPLC) was employed to analyze the A. melanoxylon flowers and phyllodes. A total of 13 compounds (accounting for most abundant compounds in flowers and phyllodes) include different flavonoids and phenolic compounds. The phytochemical compounds detected were: Gallic acid, protocatechuic acid, p-hydroxybenzoic acid, p-hydroxybenzaldehyde, vanillic acid, syringic acid, p-coumaric acid, and ferulic acid. The major flavonoid compounds identified include rutin, luteolin, apigenin, and catechin. Allelopathic effects of flower and phyllodes extracts from A. melanoxylon may be due to the presence of above compounds identified by HPLC analysis.
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Affiliation(s)
- M. Iftikhar Hussain
- Department of Plant Biology and Soil Science, Faculty of Biology, University of Vigo, Campus Lagoas-Marcosende, E-36310 Vigo, Spain;
- CITACA, Agri-Food Research and Transfer Cluster, Campus da Auga, University of Vigo, 32004 Ourense, Spain
- Correspondence:
| | - Mohamed A. El-Sheikh
- Botany & Microbiology Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia;
| | - Manuel J. Reigosa
- Department of Plant Biology and Soil Science, Faculty of Biology, University of Vigo, Campus Lagoas-Marcosende, E-36310 Vigo, Spain;
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Gfeller V, Huber M, Förster C, Huang W, Köllner TG, Erb M. Root volatiles in plant-plant interactions I: High root sesquiterpene release is associated with increased germination and growth of plant neighbours. PLANT, CELL & ENVIRONMENT 2019; 42:1950-1963. [PMID: 30737807 PMCID: PMC6850102 DOI: 10.1111/pce.13532] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/18/2019] [Accepted: 01/19/2019] [Indexed: 05/08/2023]
Abstract
Volatile organic compounds (VOCs) emitted by plant leaves can influence the physiology of neighbouring plants. In contrast to leaf VOCs, little is known about the role of root VOCs in plant-plant interactions. Here, we characterize constitutive root VOC emissions of the spotted knapweed (Centaurea stoebe) and explore the impact of these VOCs on the germination and growth of different sympatric plant species. We show that C. stoebe roots emit high amounts of sesquiterpenes, with estimated release rates of (E)-β-caryophyllene above 3 μg g-1 dw hr-1 . Sesquiterpene emissions show little variation between different C. stoebe populations but vary substantially between different Centaurea species. Through root transcriptome sequencing, we identify six root-expressed sesquiterpene synthases (TPSs). Two root-specific TPSs, CsTPS4 and CsTPS5, are sufficient to produce the full blend of emitted root sesquiterpenes. VOC-exposure experiments demonstrate that C. stoebe root VOCs have neutral to positive effects on the germination and growth of different sympatric neighbours. Thus, constitutive root sesquiterpenes produced by two C. stoebe TPSs are associated with facilitation of sympatric neighbouring plants. The release of root VOCs may thus influence plant community structure in nature.
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Affiliation(s)
- Valentin Gfeller
- Institute of Plant SciencesUniversity of Bern3013BernSwitzerland
| | - Meret Huber
- Department of BiochemistryMax Planck Institute for Chemical Ecology07745JenaGermany
| | - Christiane Förster
- Department of BiochemistryMax Planck Institute for Chemical Ecology07745JenaGermany
| | - Wei Huang
- Institute of Plant SciencesUniversity of Bern3013BernSwitzerland
- Key Laboratory of Aquatic Plant and Watershed Ecology, Wuhan Botanical GardenChinese Academy of SciencesWuhan430074HubeiChina
| | - Tobias G. Köllner
- Department of BiochemistryMax Planck Institute for Chemical Ecology07745JenaGermany
| | - Matthias Erb
- Institute of Plant SciencesUniversity of Bern3013BernSwitzerland
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Jones GL, Tomlinson M, Owen R, Scullion J, Winters A, Jenkins T, Ratcliffe J, Gwynn-Jones D. Shrub establishment favoured and grass dominance reduced in acid heath grassland systems cleared of invasive Rhododendron ponticum. Sci Rep 2019; 9:2239. [PMID: 30783123 PMCID: PMC6381222 DOI: 10.1038/s41598-019-38573-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 12/14/2018] [Indexed: 11/29/2022] Open
Abstract
Rhododendron ponticum L. is a damaging invasive alien species in Britain, favouring the moist, temperate climate, and the acidic soils of upland areas. It outshades other species and is thought to create a soil environment of low pH that may be higher in phytotoxic phenolic compounds. We investigated native vegetation restoration and R. ponticum regeneration post-clearance using heathland sites within Snowdonia National Park, Wales; one site had existing R. ponticum stands and three were restoring post-clearance. Each site also had an adjacent, uninvaded control for comparison. We assessed whether native vegetation restoration was influenced post-invasion by soil chemical properties, including pH and phytotoxic compounds, using Lactuca sativa L. (lettuce) bioassays supported by liquid chromatography-mass spectroscopy (LC-MSn). Cleared sites had higher shrub and bare ground cover, and lower grass and herbaceous species cover relative to adjacent uninvaded control sites; regenerating R. ponticum was also observed on all cleared sites. No phenolic compounds associated with R. ponticum were identified in any soil water leachates, and soil leachates from cleared sites had no inhibitory effect in L. sativa germination assays. We therefore conclude that reportedly phytotoxic compounds do not influence restoration post R. ponticum clearance. Soil pH however was lower beneath R. ponticum and on cleared sites, relative to adjacent uninvaded sites. The lower soil pH post-clearance may have favoured shrub species, which are typically tolerant of acidic soils. The higher shrub cover on cleared sites may have greater ecological value than unaffected grass dominated sites, particularly given the recent decline in such valuable heathland habitats. The presence of regenerating R. ponticum on all cleared sites however highlights the critical importance of monitoring and re-treating sites post initial clearance.
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Affiliation(s)
- Gruffydd Lloyd Jones
- IBERS, Aberystwyth University, Penglais Campus, Aberystwyth, Ceredigion, SY23 3DA, UK
- Snowdonia National Park Authority, National Park Office, Penrhyndeudraeth, Gwynedd, LL48 6LF, UK
| | - Max Tomlinson
- IBERS, Aberystwyth University, Penglais Campus, Aberystwyth, Ceredigion, SY23 3DA, UK
| | - Rhys Owen
- Snowdonia National Park Authority, National Park Office, Penrhyndeudraeth, Gwynedd, LL48 6LF, UK
| | - John Scullion
- IBERS, Aberystwyth University, Penglais Campus, Aberystwyth, Ceredigion, SY23 3DA, UK
| | - Ana Winters
- IBERS, Aberystwyth University, Penglais Campus, Aberystwyth, Ceredigion, SY23 3DA, UK
| | - Tom Jenkins
- Forest Research, Thoday Building, Deiniol Road, Bangor, Gwynedd, LL57 2UW, UK
| | - John Ratcliffe
- Natural Resources Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 4DE, UK
| | - Dylan Gwynn-Jones
- IBERS, Aberystwyth University, Penglais Campus, Aberystwyth, Ceredigion, SY23 3DA, UK.
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Phytotoxic Compounds Isolated from Leaves of the Invasive Weed Xanthium spinosum. Molecules 2018; 23:molecules23112840. [PMID: 30388777 PMCID: PMC6278460 DOI: 10.3390/molecules23112840] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 10/26/2018] [Accepted: 10/28/2018] [Indexed: 12/04/2022] Open
Abstract
The aim of this study was to identify bioactive compounds from leaves of the invasive plant Xanthium spinosum and assess their phytotoxic activity. Activity-guided fractionation led to the isolation of 6 bioactive compounds: xanthatin (1), 1α,5α-epoxyxanthatin (2), 4-epiisoxanthanol (3), 4-epixanthanol (4), loliolide (5) and dehydrovomifoliol (6). Of them, compounds 2–6 were isolated from the X. spinosum for the first time. The structures of 1–6 were elucidated on the basis of extensive NMR studies and ESI-MS measurements as well as comparison with literature data. All of compounds were evaluated for their phytotoxic activity. Among them, compounds 1–4 exhibited stronger activity on 2 receiver plants compared with the other 2 compounds, with xanthatin (1) being the most potent compound, which suppressed root growth of the dicot plant Amaranthus retroflexus by 32.5%, 39.4%, 84.7% when treated xanthatin (1) at 5, 20, and 100 µg/mL, while for the monocot plant, root growth was inhibited by 14.7%, 28.0%, and 40.0%, respectively. Seedling growth was nearly completely inhibited when the concentration of xanthanolides increased to 500 µg/mL, whereas there was still some seedling growth when loliolide (5) and dehydrovomifoliol (6) were applied at the same concentration. Dehydrovomifoliol (6) did not negatively affect seedling growth of P. annua at all tested concentrations, and root length was still 42.0% of the control when the highest concentration 500 µg/mL was used. This is the first report of the phytotoxicity of 1α,5α-epoxyxanthatin (2), 4-epiisxanthanol (3) and 4-epixanthanol (4). These compounds have the potential to be utilized as natural herbicides, especially 4-epiisoxanthanol (3), which exhibited significant selective activity between the dicot and monocot plants. On the other hand, whether these bioactive substances serve as allelochemicals to facilitate the invasion success of X. spinosum needs to be further studied.
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Uddin MN, Robinson RW. Allelopathy and resource competition: the effects of Phragmites australis invasion in plant communities. BOTANICAL STUDIES 2017; 58:29. [PMID: 28664396 PMCID: PMC5491426 DOI: 10.1186/s40529-017-0183-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 06/16/2017] [Indexed: 05/29/2023]
Abstract
BACKGROUND Phragmites australis, a ubiquitous wetland plant, has been considered one of the most invasive species in the world. Allelopathy appears to be one of the invasion mechanisms, however, the effects could be masked by resource competition among target plants. The difficulty of distinguishing allelopathy from resource competition among plants has hindered investigations of the role of phytotoxic allelochemicals in plant communities. This has been addressed via experiments conducted in both the greenhouse and laboratory by growing associated plants, Melaleuca ericifolia, Rumex conglomeratus, and model plant, Lactuca sativa at varying densities with the allelopathic plant, P. australis, its litter and leachate of P. australis litter. This study investigated the potential interacting influences of allelopathy and resource competition on plant growth-density relationships. RESULTS In greenhouse, the root exudates mediated effects showed the strongest growth inhibition of M. ericifolia at high density whereas litter mediated results revealed increased growth at medium density treatments compared to low and high density. Again, laboratory experiments related to seed germination and seedling growth of L. sativa and R. conglomeratus exhibited phytotoxicity decreased showing positive growth as plant density increased and vice versa. Overall, the differential effects were observed among experiments but maximum individual plant biomass and some other positive effects on plant traits such as root and shoot length, chlorophyll content occurred at an intermediate density. This was attributed to the sharing of the available phytotoxin among plants at high densities which is compatible to density-dependent phytotoxicity model. CONCLUSIONS The results demonstrated that plant-plant interference is the combined effect of allelopathy and resource competition with many other factors but this experimental design, target-neighbor mixed-culture in combination of plant grown at varying densities with varying level of phytotoxins, mono-culture, can successfully separate allelopathic effects from competition.
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Affiliation(s)
- Md Nazim Uddin
- Department of Ecology & Environmental Management, College of Engineering & Science, Victoria University, Melbourne, VIC 8001 Australia
- Institute for Sustainability & Innovation, Victoria University, Melbourne, VIC 8001 Australia
| | - Randall William Robinson
- Department of Ecology & Environmental Management, College of Engineering & Science, Victoria University, Melbourne, VIC 8001 Australia
- Institute for Sustainability & Innovation, Victoria University, Melbourne, VIC 8001 Australia
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Lekberg Y, Wagner V, Rummel A, McLeod M, Ramsey PW. Strong indirect herbicide effects on mycorrhizal associations through plant community shifts and secondary invasions. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:2359-2368. [PMID: 28851018 DOI: 10.1002/eap.1613] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 07/07/2017] [Accepted: 07/18/2017] [Indexed: 06/07/2023]
Abstract
Million of acres of U.S. wildlands are sprayed with herbicides to control invasive species, but relatively little is known about non-target effects of herbicide use. We combined greenhouse, field, and laboratory experiments involving the invasive forb spotted knapweed (Centaurea stoebe) and native bunchgrasses to assess direct and indirect effects of the forb-specific herbicide picloram on arbuscular mycorrhizal fungi (AMF), which are beneficial soil fungi that colonize most plants. Picloram had no effect on bunchgrass viability and their associated AMF in the greenhouse, but killed spotted knapweed and reduced AMF colonization of a subsequent host grown. Results were similar in the field where AMF abundance in bunchgrass-dominated plots was unaffected by herbicides one year after spraying based on 16:1ω5 phospholipid fatty acid (PLFA) and neutral lipid fatty acid (NLFA) concentrations. In spotted-knapweed-dominated plots, however, picloram application shifted dominance from spotted knapweed, a good AMF host, to bulbous bluegrass (Poa bulbosa), a poor AMF host. This coincided with a 63% reduction in soil 16:1ω5 NLFA concentrations but no reduction of 16:1ω5 PLFA. Because 16:1ω5 NLFA quantifies AMF storage lipids and 16:1ω5 PLFA occurs in AMF membrane lipids, we speculate that the herbicide-mediated reduction in host quality reduced fungal carbon storage, but not necessarily fungal abundance after one year in the field. Overall, in greenhouse and field experiments, AMF were only affected when picloram altered host quantity and quality. This apparent lack of direct effect was supported by our in-vitro trial where picloram applied to AMF mycelia did not reduce fungal biomass and viability. We show that the herbicide picloram can have profound, indirect effects on AMF within one year. Depending on herbicide-mediated shifts in host quality, rapid interventions may be necessary post herbicide applications to prevent loss of AMF abundance. Future research should assess consequences of these potential shifts for the restoration of native plants that differ in mycorrhizal dependency.
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Affiliation(s)
- Ylva Lekberg
- MPG Ranch, 1001 South Higgins Avenue, Suite A3, Missoula, Montana, 59801, USA
- Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana, 59802, USA
| | - Viktoria Wagner
- Department of Botany and Zoology, Masaryk University, Kotlářská 2, CZ-611 37, Brno, Czech Republic
| | - Alexii Rummel
- MPG Ranch, 1001 South Higgins Avenue, Suite A3, Missoula, Montana, 59801, USA
| | - Morgan McLeod
- MPG Ranch, 1001 South Higgins Avenue, Suite A3, Missoula, Montana, 59801, USA
| | - Philip W Ramsey
- MPG Ranch, 1001 South Higgins Avenue, Suite A3, Missoula, Montana, 59801, USA
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Kato-Noguchi H, Kimura F, Ohno O, Suenaga K. Involvement of allelopathy in inhibition of understory growth in red pine forests. JOURNAL OF PLANT PHYSIOLOGY 2017; 218:66-73. [PMID: 28779633 DOI: 10.1016/j.jplph.2017.07.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 07/07/2017] [Accepted: 07/10/2017] [Indexed: 06/07/2023]
Abstract
Japanese red pine (Pinus densiflora Sieb. et Zucc.) forests are characterized by sparse understory vegetation although sunlight intensity on the forest floor is sufficient for undergrowth. The possible involvement of pine allelopathy in the establishment of the sparse understory vegetation was investigated. The soil of the red pine forest floor had growth inhibitory activity on six test plant species including Lolium multiflorum, which was observed at the edge of the forest but not in the forest. Two growth inhibitory substances were isolated from the soil and characterized to be 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid. Those compounds are probably formed by degradation process of resin acids. Resin acids are produced by pine and delivered into the soil under the pine trees through balsam and defoliation. Threshold concentrations of 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid for the growth inhibition of L. multiflorum were 30 and 10μM, respectively. The concentrations of 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid in the soil were 312 and 397μM, respectively, which are sufficient concentrations to cause the growth inhibition because of the threshold. These results suggest that those compounds are able to work as allelopathic agents and may prevent from the invasion of herbaceous plants into the forests by inhibiting their growth. Therefore, allelopathy of red pine may be involved in the formation of the sparse understory vegetation.
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Affiliation(s)
- Hisashi Kato-Noguchi
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan.
| | - Fukiko Kimura
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan
| | - Osamu Ohno
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama 223-8522, Japan
| | - Kiyotake Suenaga
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama 223-8522, Japan
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Schulz M, Sicker D, Schackow O, Hennig L, Yurkov A, Siebers M, Hofmann D, Disko U, Ganimede C, Mondani L, Tabaglio V, Marocco A. Interspecies-cooperations of abutilon theophrasti with root colonizing microorganisms disarm BOA-OH allelochemicals. PLANT SIGNALING & BEHAVIOR 2017; 12:e1358843. [PMID: 28786736 PMCID: PMC5616163 DOI: 10.1080/15592324.2017.1358843] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/18/2017] [Accepted: 07/18/2017] [Indexed: 06/07/2023]
Abstract
A facultative, microbial micro-community colonizing roots of Abutilon theophrasti Medik. supports the plant in detoxifying hydroxylated benzoxazolinones. The root micro-community is composed of several fungi and bacteria with Actinomucor elegans as a dominant species. The yeast Papiliotrema baii and the bacterium Pantoea ananatis are actively involved in the detoxification of hydroxylated benzoxazolinones by generating H2O2. At the root surface, laccases, peroxidases and polyphenol oxidases cooperate for initiating polymerization reactions, whereby enzyme combinations seem to differ depending on the hydroxylation position of BOA-OHs. A glucosyltransferase, able to glucosylate the natural benzoxazolinone detoxification intermediates BOA-5- and BOA-6-OH, is thought to reduce oxidative overshoots by damping BOA-OH induced H2O2 generation. Due to this detoxification network, growth of Abutilon theophrasti seedlings is not suppressed by BOA-OHs. Polymer coats have no negative influence. Alternatively, quickly degradable 6-hydroxy-5-nitrobenzo[d]oxazol-2(3H)-one can be produced by the micro-community member Pantoea ananatis at the root surfaces. The results indicate that Abutilon theophrasti has evolved an efficient strategy by recruiting soil microorganisms with special abilities for different detoxification reactions which are variable and may be triggered by the allelochemical´s structure and by environmental conditions.
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Affiliation(s)
- Margot Schulz
- IMBIO Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Bonn, Germany
| | - Dieter Sicker
- Institut für Organische Chemie, Universität Leipzig, Leipzig, Germany
| | - Oliver Schackow
- Institut für Organische Chemie, Universität Leipzig, Leipzig, Germany
| | - Lothar Hennig
- Institut für Organische Chemie, Universität Leipzig, Leipzig, Germany
| | - Andrey Yurkov
- DSMZ Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Braunschweig, Germany
| | - Meike Siebers
- IMBIO Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Bonn, Germany
| | - Diana Hofmann
- IBG-3: Agrossphäre, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Ulrich Disko
- IBG-3: Agrossphäre, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Cristina Ganimede
- Institute of Agronomy, Genetics and Field Crops, Università Cattolica del Sacro Cuore, Piacenza, Italy
| | - Letizia Mondani
- Institute of Agronomy, Genetics and Field Crops, Università Cattolica del Sacro Cuore, Piacenza, Italy
| | - Vincenzo Tabaglio
- Institute of Agronomy, Genetics and Field Crops, Università Cattolica del Sacro Cuore, Piacenza, Italy
| | - Adriano Marocco
- Institute of Agronomy, Genetics and Field Crops, Università Cattolica del Sacro Cuore, Piacenza, Italy
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Reinhardt JR, Nagel LM, Swanston CW, Keough H. Community-Level Impacts of Management and Disturbance in Western Michigan Oak Savannas. AMERICAN MIDLAND NATURALIST 2017. [DOI: 10.1674/0003-0031-177.1.112] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Xuan TD, Anh LH, Khang DT, Tuyen PT, Minh TN, Khanh TD, Trung KH. Weed Allelochemicals and Possibility for Pest Management. INTERNATIONAL LETTERS OF NATURAL SCIENCES 2016. [DOI: 10.56431/p-5t246m] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Purpose: Weed interference is a constraint in agricultural practice. The crop-weed interaction has been extensively described in literature, but the weed-weed interaction and their potential usage in crop production have not much been understood. In this paper, the interactions of allelochemicals of the weeds which cause troublesome in crop production and ecosystem against weeds, crops, and pathogens are described.
Principal results: Weed allelochemicals are classified into many chemical classes, and the majority is consisting of phenolics acids, alkaloids, terpenes, flavonoids, long chain fatty acids, lactones, and other volatile compounds. Type of weed allelochemicals and their doses are varied among weed species. Some allelochemicals such as catechin (+/-) have been reported to be responsible for weed invasiveness. Some crops exude germination stimulants to parasitic weeds such as Striga spp. and Orobanche spp. In contrast to their negative impacts on crop production, many weeds can be exploited as promising sources to control harmful insects, fungi, bacteria, and weeds. For instance, Ageratum conyzoides is a destructive weed in crop production, but it exerted excellent insecticidal, antifungal, and herbicidal capacity and promoted citrus productivity in A. conyzoides intercropped citrus orchards.
Major conclusions: In general, weeds compete with crops by chemical pathway by releasing plant growth inhibitors to reduce crop growth. Weed allelochemicals may be successfully exploited for pest and weed controls in an integrated sustainable crop productoiin. Some weed allelochemicals are potent for development of natural pesticides.
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17
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Xuan TD, Anh LH, Khang DT, Tuyen PT, Minh TN, Khanh TD, Trung KH. Weed Allelochemicals and Possibility for Pest Management. INTERNATIONAL LETTERS OF NATURAL SCIENCES 2016. [DOI: 10.18052/www.scipress.com/ilns.56.25] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Purpose: Weed interference is a constraint in agricultural practice. The crop-weed interaction has been extensively described in literature, but the weed-weed interaction and their potential usage in crop production have not much been understood. In this paper, the interactions of allelochemicals of the weeds which cause troublesome in crop production and ecosystem against weeds, crops, and pathogens are described.Principal results: Weed allelochemicals are classified into many chemical classes, and the majority is consisting of phenolics acids, alkaloids, terpenes, flavonoids, long chain fatty acids, lactones, and other volatile compounds. Type of weed allelochemicals and their doses are varied among weed species. Some allelochemicals such as catechin (+/-) have been reported to be responsible for weed invasiveness. Some crops exude germination stimulants to parasitic weeds such asStrigaspp. andOrobanchespp. In contrast to their negative impacts on crop production, many weeds can be exploited as promising sources to control harmful insects, fungi, bacteria, and weeds. For instance,Ageratum conyzoidesis a destructive weed in crop production, but it exerted excellent insecticidal, antifungal, and herbicidal capacity and promoted citrus productivity inA. conyzoidesintercropped citrus orchards.Major conclusions: In general, weeds compete with crops by chemical pathway by releasing plant growth inhibitors to reduce crop growth. Weed allelochemicals may be successfully exploited for pest and weed controls in an integrated sustainable crop productoiin. Some weed allelochemicals are potent for development of natural pesticides.
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18
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Kato-Noguchi H, Saito Y, Ohno O, Suenaga K. A phytotoxic active substance in the decomposing litter of the fern Gleichenia japonica. JOURNAL OF PLANT PHYSIOLOGY 2015; 176:55-60. [PMID: 25569852 DOI: 10.1016/j.jplph.2014.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 12/03/2014] [Accepted: 12/03/2014] [Indexed: 06/04/2023]
Abstract
The fern Gleichenia japonica often dominates plant communities by forming large monospecific stands throughout the temperate to tropical Asia. The objective of this study was the investigation of allelopathic property and substances of the decomposing litter of the fern to evaluate the possible involvement of its allelopathy in the domination. An aqueous methanol extract of G. japonica litter inhibited the growth of garden cress (Lepidium sativum), lettuce (Lactuca sativa), barnyard grass (Echinochloa crus-galli), and ryegrass (Lolium multiflorum). This result suggests that G. japonica litter contains growth inhibitory substances. The extract was purified by chromatography while monitoring the inhibitory activity, and a growth inhibitory substance was isolated. The chemical structure of the substance was determined by spectral data to be a novel compound, 13-O-β-fucopyranosyl-3β-hydroxymanool. This compound inhibited root and shoot growth of garden cress and barnyard grass at concentrations ranging from 89.7 to 271 μM for 50% inhibition. In addition, the compound had potent growth inhibitory activity with the soil taken from near the colony. The concentration of the compound in soil under a pure colony of G. japonica was 790 μM, suggesting that the compound may contribute to the establishment of monocultural stands by this fern.
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Affiliation(s)
- Hisashi Kato-Noguchi
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan.
| | - Yoshihumi Saito
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan
| | - Osamu Ohno
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama 223-8522, Japan
| | - Kiyotake Suenaga
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama 223-8522, Japan
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19
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Gibson DM, Vaughan RH, Milbrath LR. Invasive swallow-worts: an allelopathic role for -(-) antofine remains unclear. J Chem Ecol 2015; 41:202-11. [PMID: 25653045 DOI: 10.1007/s10886-015-0552-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 01/20/2015] [Accepted: 01/23/2015] [Indexed: 11/28/2022]
Abstract
Pale swallow-wort (Vincetoxicum rossicum) and black swallow-wort (V. nigrum) are two invasive plant species in the northeastern United States and eastern Canada that have undergone rapidly expanding ranges over the past 30 years. Both species possess a highly bioactive phytotoxin -(-) antofine in root tissues that causes pronounced inhibition in laboratory bioassays of native plant species co-located in habitats where swallow-wort is found. To further evaluate the allelopathic potential of -(-) antofine, we: determined its concentration in young plant tissues; used in situ approaches to assess antofine stability, potential activity of degradation products, activity in sterile and nonsterile soil; and determined accumulation and concentration in hydroponic cultivation and field collected soil samples. Extracts of seeds and young seedlings were found to have approximately 2-3 times the level of -(-) antofine in comparison to root extracts of adult plants. Breakdown products of antofine accumulated rapidly with exposure to light, but more slowly in the dark, at ambient temperatures, and these products did not retain biological activity. Extraction efficiencies of control soil spiked with -(-) antofine were low but easily detectable by HPLC. Soil samples collected over two growing seasons at four different sites where either pale swallow-wort or black swallow-wort populations are present were negative for the presence of -(-) antofine. Dose response curves using sterile and nonsterile soil spiked with -(-) antofine demonstrated a requirement for at least 20-55 × greater -(-) antofine concentrations in soil to produce similar phytotoxic effects to those previously seen in agar bioassays with lettuce seedlings. Sterile soil had a calculated EC50 of 686 μM (250 μg/g) as compared to nonsterile soil treatments with a calculated EC50 of 1.88 mM (640 μg/g). When pale swallow-wort and black swallow-wort adult plants were grown in hydroponic cultivation, -(-) antofine was found in root exudates and in the growing medium in the nM range. The concentrations in exudate were much lower than that needed for biological activity (μM) although they might be an underestimate of what may accumulate over time in an undisturbed rhizosphere. Based on these various results, it remains uncertain as to whether -(-) antofine could play a significant allelopathic role for invasive swallow-worts.
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Affiliation(s)
- Donna M Gibson
- USDA, Agricultural Research Service, Biological Integrated Pest Management Research Unit, Robert W. Holley Center for Agriculture and Health, Tower Road, Ithaca, NY, 14853, USA
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20
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Lewis KC, Porter RD. Global approaches to addressing biofuel-related invasive species risks and incorporation into U.S. laws and policies. ECOL MONOGR 2014. [DOI: 10.1890/13-1625.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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21
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Novaes P, Imatomi M, Varela RM, Molinillo JMG, Lacret R, Gualtieri SCJ, Macías FA. Allelopathic potential of Rapanea umbellata leaf extracts. Chem Biodivers 2014; 10:1539-48. [PMID: 23939802 DOI: 10.1002/cbdv.201200367] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Indexed: 11/06/2022]
Abstract
The stressful conditions associated with the Brazilian savanna (Cerrado) environment were supposed to favor higher levels of allelochemicals in Rapanea umbellata from this ecosystem. The allelopathic potential of R. umbellata leaf extracts was studied using the etiolated wheat coleoptile and standard phytotoxicity bioassays. The most active extract was selected to perform a bioassay-guided isolation, which allowed identifying lutein (1) and (-)-catechin (2) as potential allelochemicals. Finally, the general bioactivity of the two compounds was studied, which indicated that the presence of 1 might be part of the defense mechanisms of this plant.
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Affiliation(s)
- Paula Novaes
- Departamento de Botanica, Universidade Federal de São Carlos, Rodovia Washington Luís, km 235, São Carlos - São Paulo, CEP 13565-905, Brazil
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22
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Knudsmark Jessing K, Duke SO, Cedergreeen N. Potential ecological roles of artemisinin produced by Artemisia annua L. J Chem Ecol 2014; 40:100-17. [PMID: 24500733 DOI: 10.1007/s10886-014-0384-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 10/16/2013] [Accepted: 01/21/2014] [Indexed: 11/24/2022]
Abstract
Artemisia annua L. (annual wormwood, Asteraceae) and its secondary metabolite artemisinin, a unique sesquiterpene lactone with an endoperoxide bridge, has gained much attention due to its antimalarial properties. Artemisinin has a complex structure that requires a significant amount of energy for the plant to synthesize. So, what are the benefits to A. annua of producing this unique compound, and what is the ecological role of artemisinin? This review addresses these questions, discussing evidence of the potential utility of artemisinin in protecting the plant from insects and other herbivores, as well as pathogens and competing plant species. Abiotic factors affecting the artemisinin production, as well as mechanisms of artemisinin release to the surroundings also are discussed, and new data are provided on the toxicity of artemisinin towards soil and aquatic organisms. The antifungal and antibacterial effects reported are not very pronounced. Several studies have reported that extracts of A. annua have insecticidal effects, though few studies have proven that artemisinin could be the single compound responsible for the observed effects. However, the pathogen(s) or insect(s) that may have provided the selection pressure for the evolution of artemisinin synthesis may not have been represented in the research thus far conducted. The relatively high level of phytotoxicity of artemisinin in soil indicates that plant/plant allelopathy could be a beneficial function of artemisinin to the producing plant. The release routes of artemisinin (movement from roots and wash off from leaf surfaces) from A. annua to the soil support the rationale for allelopathy.
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Affiliation(s)
- Karina Knudsmark Jessing
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark,
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The impact of microbial biotransformation of catechin in enhancing the allelopathic effects of Rhododendron formosanum. PLoS One 2013; 8:e85162. [PMID: 24391991 PMCID: PMC3877349 DOI: 10.1371/journal.pone.0085162] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Accepted: 11/23/2013] [Indexed: 11/19/2022] Open
Abstract
Rhododendron formosanum is distributed widely in the central mountains in Taiwan and the major allelopathic compound in the leaves has been identified as (-)-catechin, which is also a major allelochemical of an invasive spotted knapweed in North America. Soil microorganisms play key roles in ecosystems and influence various important processes, including allelopathy. However, no microorganism has been identified as an allelochemical mediator. This study focused on the role of microorganisms in the allelopathic effects of R. formosanum. The microorganism population in the rhizosphere of R. formosanum was investigated and genetic analysis revealed that the predominant genera of microorganisms in the rhizosphere of R. formosanum were Pseudomonas, Herbaspirillum, and Burkholderia. The dominant genera Pseudomonas utilized (-)-catechin as the carbon source and catalyzed the conversion of (-)-catechin into protocatechuic acid in vitro. The concentrations of allelochemicals in the soil were quantified by liquid chromatography-electrospray ionization/tandem mass spectrometry. The concentration of (-)-catechin in the soil increased significantly during the extreme rainfall in the summer season and suppressed total bacterial populations. Protocatechuic acid accumulation was observed while total bacterial populations increased abundantly in both laboratory and field studies. Allelopathic interactions were tested by evaluating the effects of different allelochemicals on the seed germination, radicle growth, and photosynthesis system II of lettuce. Protocatechuic acid exhibited higher phytotoxicity than (-)-catechin did and the effect of (-)-catechin on the inhibition of seed germination was enhanced by combining it with protocatechuic acid at a low concentration. This study revealed the significance of the allelopathic interactions between R. formosanum and microorganisms in the rhizosphere. These findings demonstrate that knowledge regarding the precise biotransformation process of (-)-catechin by microorganisms in the environment is necessary to increase our understanding of allelopathy.
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Enge S, Nylund GM, Harder T, Pavia H. An exotic chemical weapon explains low herbivore damage in an invasive alga. Ecology 2013; 93:2736-45. [PMID: 23431603 DOI: 10.1890/12-0143.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Invasion success of introduced species is often attributed to a lack of natural enemies as stated by the enemy release hypothesis (ERH). The ERH intuitively makes sense for specialized enemies, but it is less evident why invaders in their new area escape attacks by generalist enemies. A recent hypothesis explains low herbivore damage on invasive plants with plant defense chemicals that are evolutionarily novel to native herbivores. Support for this novel weapon hypothesis (NWH) is so far based on circumstantial evidence. To corroborate the NWH, there is a need for direct evidence through explicit characterizations of the novel chemicals and their effects on native consumers. This study evaluated the NWH using the highly invasive red alga Bonnemaisonia hamifera. In pairwise feeding experiments, preferences between B. hamifera and native competitors were assessed for four common generalist herbivores in the invaded area. Through a bioassay-guided fractionation, we identified the deterrent compound and verified its effect in an experiment with the synthesized compound at natural concentrations. The results showed that native herbivores strongly preferred native algae to B. hamifera. The resistance against herbivores could be tracked down to the algal metabolite 1,1,3,3-tetrabromo-2-heptanone, a compound not known from native algae in the invaded area. The importance of the chemical defense was further underlined by the feeding preference of herbivores for individuals with a depleted content of 1,1,3,3-tetrabromo-2-heptanone. This study thus provides the first conclusive example of a highly successful invader where low consumption in the new range can be directly attributed to a specific chemical defense against evolutionarily naive native generalists. In conclusion, our results support the notion that novel chemical weapons against naive herbivores can provide a mechanistic explanation for plant invasion success.
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Affiliation(s)
- Swantje Enge
- Department of Biological and Environmental Sciences-Tjärnö, University of Gothenburg, 45296 Strömstad, Sweden.
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25
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Hagan DL, Jose S, Lin CH. Allelopathic exudates of cogongrass (Imperata cylindrica): implications for the performance of native pine savanna plant species in the southeastern US. J Chem Ecol 2013; 39:312-22. [PMID: 23334457 DOI: 10.1007/s10886-013-0241-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 11/21/2012] [Accepted: 01/04/2013] [Indexed: 11/30/2022]
Abstract
We conducted a greenhouse study to assess the effects of cogongrass (Imperata cylindrica) rhizochemicals on a suite of plants native to southeastern US pine savanna ecosystems. Our results indicated a possible allelopathic effect, although it varied by species. A ruderal grass (Andropogon arctatus) and ericaceous shrub (Lyonia ferruginea) were unaffected by irrigation with cogongrass soil "leachate" (relative to leachate from mixed native species), while a mid-successional grass (Aristida stricta Michx. var. beyrichiana) and tree (Pinus elliottii) were negatively affected. For A. stricta, we observed a 35.7 % reduction in aboveground biomass, a 21.9 % reduction in total root length, a 24.6 % reduction in specific root length and a 23.5 % reduction in total mycorrhizal root length, relative to the native leachate treatment. For P. elliottii, there was a 19.5 % reduction in percent mycorrhizal colonization and a 20.1 % reduction in total mycorrhizal root length. Comparisons with a DI water control in year two support the possibility that the treatment effects were due to the negative effects of cogongrass leachate, rather than a facilitative effect from the mixed natives. Chemical analyses identified 12 putative allelopathic compounds (mostly phenolics) in cogongrass leachate. The concentrations of most compounds were significantly lower, if they were present at all, in the native leachate. One compound was an alkaloid with a speculated structure of hexadecahydro-1-azachrysen-8-yl ester (C23H33NO4). This compound was not found in the native leachate. We hypothesize that the observed treatment effects may be attributable, at least partially, to these qualitative and quantitative differences in leachate chemistry.
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Affiliation(s)
- Donald L Hagan
- School of Agricultural, Forest, and Environmental Sciences, Clemson University, 212 Lehotsky Hall, Clemson, SC 29634, USA.
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Cipollini D, Rigsby CM, Barto EK. Microbes as targets and mediators of allelopathy in plants. J Chem Ecol 2012; 38:714-27. [PMID: 22585095 DOI: 10.1007/s10886-012-0133-7] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 04/27/2012] [Accepted: 05/01/2012] [Indexed: 10/28/2022]
Abstract
Studies of allelopathy in terrestrial systems have experienced tremendous growth as interest has risen in describing biochemical mechanisms responsible for structuring plant communities, determining agricultural and forest productivity, and explaining invasive behaviors in introduced organisms. While early criticisms of allelopathy involved issues with allelochemical production, stability, and degradation in soils, an understanding of the chemical ecology of soils and its microbial inhabitants has been increasingly incorporated in studies of allelopathy, and recognized as an essential predictor of the outcome of allelopathic interactions between plants. Microbes can mediate interactions in a number of ways with both positive and negative outcomes for surrounding plants and plant communities. In this review, we examine cases where soil microbes are the target of allelopathic plants leading to indirect effects on competing plants, provide examples where microbes play either a protective effect on plants against allelopathic competitors or enhance allelopathic effects, and we provide examples where soil microbial communities have changed through time in response to allelopathic plants with known or potential effects on plant communities. We focus primarily on interactions involving wild plants in natural systems, using case studies of some of the world's most notorious invasive plants, but we also provide selected examples from agriculturally managed systems. Allelopathic interactions between plants cannot be fully understood without considering microbial participants, and we conclude with suggestions for future research.
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Affiliation(s)
- Don Cipollini
- Department of Biological Sciences, Environmental Sciences PhD Program, Wright State University, Dayton, OH, USA.
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Hassan S, Mathesius U. The role of flavonoids in root-rhizosphere signalling: opportunities and challenges for improving plant-microbe interactions. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:3429-44. [PMID: 22213816 DOI: 10.1093/jxb/err430] [Citation(s) in RCA: 361] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The flavonoid pathway produces a diverse array of plant compounds with functions in UV protection, as antioxidants, pigments, auxin transport regulators, defence compounds against pathogens and during signalling in symbiosis. This review highlights some of the known function of flavonoids in the rhizosphere, in particular for the interaction of roots with microorganisms. Depending on their structure, flavonoids have been shown to stimulate or inhibit rhizobial nod gene expression, cause chemoattraction of rhizobia towards the root, inhibit root pathogens, stimulate mycorrhizal spore germination and hyphal branching, mediate allelopathic interactions between plants, affect quorum sensing, and chelate soil nutrients. Therefore, the manipulation of the flavonoid pathway to synthesize specifically certain products has been suggested as an avenue to improve root-rhizosphere interactions. Possible strategies to alter flavonoid exudation to the rhizosphere are discussed. Possible challenges in that endeavour include limited knowledge of the mechanisms that regulate flavonoid transport and exudation, unforeseen effects of altering parts of the flavonoid synthesis pathway on fluxes elsewhere in the pathway, spatial heterogeneity of flavonoid exudation along the root, as well as alteration of flavonoid products by microorganisms in the soil. In addition, the overlapping functions of many flavonoids as stimulators of functions in one organism and inhibitors of another suggests caution in attempts to manipulate flavonoid rhizosphere signals.
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Affiliation(s)
- Samira Hassan
- Division of Plant Science, Research School of Biology, Australian National University, Linnaeus Way, Canberra, ACT 0200, Australia
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Shao H, Huang X, Wei X, Zhang C. Phytotoxic effects and a phytotoxin from the invasive plant Xanthium italicum Moretti. Molecules 2012; 17:4037-46. [PMID: 22469597 PMCID: PMC6268672 DOI: 10.3390/molecules17044037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/12/2012] [Accepted: 03/28/2012] [Indexed: 11/21/2022] Open
Abstract
The allelopathic effects of different parts of the plant Xanthium italicum Moretti were evaluated by conducting bioassays against two dicot plants, amaranth (Amaranthus mangostanus L.) and lettuce (Lectuca sativa L.), and two monocot plants, wheat (Triticum aestivum Linn) and ryegrass (Lolium multiforum). Leaf and fruit extract possessed the strongest biological activity, killing all seeds of four test species at 0.05 g/mL concentration. Fruits were chosen for further investigation because of their high biomass. This led to the isolation and identification of a phytotoxin—Xanthinosin—a known sesquiterpene lactone. Xanthinosin significantly affected seedling growth of all test species at 160 µM concentration. Cultivating seeds in 800 μM xanthinosin solution resulted in a great decrease in seedling growth of all test species, especially for the two dicot plants, amaranth and lettuce, whose root length was inhibited by 78% and 89%, respectively. By comparison, the numbers were 69% lower for wheat, and 66% for ryegrass, two monocot plants. When treated with 4 mM xanthinosin solution, seed germination of all test plants was almost completely inhibited. The possibility of utilizing xanthinosin as an eco-friendly herbicide was discussed.
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Affiliation(s)
- Hua Shao
- Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; (H.S.); (X.H.)
| | - Xiaoli Huang
- Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; (H.S.); (X.H.)
| | - Xiaoyi Wei
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China;
| | - Chi Zhang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- Author to whom correspondence should be addressed; ; Tel.: +86-991-782-3127; Fax: +86-991-788-5320
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29
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Inderjit, Wardle DA, Karban R, Callaway RM. The ecosystem and evolutionary contexts of allelopathy. Trends Ecol Evol 2011; 26:655-62. [DOI: 10.1016/j.tree.2011.08.003] [Citation(s) in RCA: 194] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 08/11/2011] [Accepted: 08/15/2011] [Indexed: 10/17/2022]
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30
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Zhu X, Zhang J, Ma K. Soil biota reduce allelopathic effects of the invasive Eupatorium adenophorum. PLoS One 2011; 6:e25393. [PMID: 21980442 PMCID: PMC3182202 DOI: 10.1371/journal.pone.0025393] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Accepted: 09/02/2011] [Indexed: 11/18/2022] Open
Abstract
Allelopathy has been hypothesized to play a role in exotic plant invasions, and study of this process can improve our understanding of how direct and indirect plant interactions influence plant community organization and ecosystem functioning. However, allelopathic effects can be highly conditional. For example allelopathic effects demonstrated in vivo can be difficult to demonstrate in field soils. Here we tested phytotoxicity of Eupatorium adenophorum (croftonweed), one of the most destructive exotic species in China, to a native plant species Brassica rapa both in sand and in native soil. Our results suggested that natural soils from different invaded habitats alleviated or eliminated the efficacy of potential allelochemicals relative to sand cultures. When that soil is sterilized, the allelopathic effects returned; suggesting that soil biota were responsible for the reduced phytotoxicity in natural soils. Neither of the two allelopathic compounds (9-Oxo-10,11-dehydroageraphorone and 9b-Hydroxyageraphorone) of E. adenophorum could be found in natural soils infested by the invader, and when those compounds were added to the soils as leachates, they showed substantial degradation after 24 hours in natural soils but not in sand. Our findings emphasize that soil biota can reduce the allelopathic effects of invaders on other plants, and therefore can reduce community invasibility. These results also suggest that soil biota may have stronger or weaker effects on allelopathic interactions depending on how allelochemicals are delivered.
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Affiliation(s)
- Xunzhi Zhu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Jintun Zhang
- College of Life Sciences, Beijing Normal University, Beijing, China
| | - Keping Ma
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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31
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Blair AC, Blumenthal D, Hufbauer RA. Hybridization and invasion: an experimental test with diffuse knapweed (Centaurea diffusa Lam.). Evol Appl 2011; 5:17-28. [PMID: 25568026 DOI: 10.1111/j.1752-4571.2011.00203.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 07/25/2011] [Indexed: 11/29/2022] Open
Abstract
A number of studies have suggested a link between hybridization and invasion. In this study, we experimentally test the potential for hybridization to influence invasion through a greenhouse common garden study. Diffuse knapweed (DK) (Centaurea diffusa Lam.) was introduced to North America with admixture from spotted knapweed (SK) (Centaurea stoebe subsp. stoebe L.). Comparisons between North American DK (including hybrid phenotypes) and native (European) DK in a common garden did not reveal enhanced performance or increased phenotypic variance, suggesting that pre-introduction hybridization or, more generally, post-introduction evolutionary change has not significantly contributed to the invasion of DK. In contrast, early generation hybrids [artificially created Backcross 1 (BC1) plants] exhibited increased variance for eight of the examined traits, and greater leaf and reproductive shoot production when compared to North American DK. Individual BC1 lines differed for several traits, suggesting the importance of the cross for drawing conclusions from such comparisons. When compared to the parental species (DK and SK), the BC1 plants were not transgressive for any of the measured traits. Overall, these findings suggest that if diploid SK is introduced to North America, interspecific hybridization has the potential to result in even more aggressive invaders.
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Affiliation(s)
- Amy C Blair
- Graduate Degree Program in Ecology and Department of Bioagricultural Sciences and Pest Management, Colorado State University Fort Collins, CO, USA
| | - Dana Blumenthal
- USDA-ARS, Rangeland Resources Research Unit Fort Collins, CO, USA
| | - Ruth A Hufbauer
- Graduate Degree Program in Ecology and Department of Bioagricultural Sciences and Pest Management, Colorado State University Fort Collins, CO, USA
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Gibson DM, Krasnoff SB, Biazzo J, Milbrath L. Phytotoxicity of antofine from invasive swallow-worts. J Chem Ecol 2011; 37:871-9. [PMID: 21739223 DOI: 10.1007/s10886-011-9994-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 06/26/2011] [Accepted: 06/28/2011] [Indexed: 11/27/2022]
Abstract
Pale swallow-wort (Vincetoxicum rossicum) and black swallow-wort (V. nigrum) are two emerging invasive plant species in the northeastern United States and southeastern Canada that have shown rapid population expansion over the past 20 years. Using bioassay-guided fractionation, the known phytochemical phenanthroindolizidine alkaloid, (-)-antofine, was identified as a potent phytotoxin in roots, leaves, and seeds of both swallow-wort species. In seedling bioassays, (-)-antofine, at μM concentrations, resulted in greatly reduced root growth of Asclepias tuberosa, A. syriaca, and Apocynum cannabinum, three related, native plant species typically found in habitats where large stands of swallow-wort are present. In contrast, antofine exhibited moderate activity against lettuce, and it had little effect on germination and root growth of either black or pale swallow-wort. In disk diffusion assays, antifungal activity was observed at 10 μg and 100 μg, while antibacterial activity was seen only at the higher level. Although both swallow-wort species display multiple growth and reproductive characteristics that may play an important role in their invasiveness, the presence of the highly bioactive phytochemical (-)-antofine in root and seed tissues indicates a potential allelopathic role in swallow-worts' invasiveness.
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Affiliation(s)
- Donna M Gibson
- USDA, Agricultural Research Service, Biological Integrated Pest Management Research Unit, Robert W. Holley Center for Agriculture and Health, Tower Road, Ithaca, NY 14853, USA.
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Bais HP, Kaushik S. Catechin secretion and phytotoxicity: Fact not fiction. Commun Integr Biol 2011; 3:468-70. [PMID: 21057643 DOI: 10.4161/cib.3.5.12559] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 05/27/2010] [Indexed: 11/19/2022] Open
Abstract
Research indicates that the invasiveness of Centaurea stoebe is attributed to the stronger allelopathic effects on the native North American species than on the related European species, which is one of the unquestionable aspects of the "novel weapons hypothesis (NWH)." Studies originating from controlled to field conditions have shown that C. stoebe utilizes its biochemical potential to exert its invasiveness. The roots of C. stoebe secrete a potent phytotoxin, catechin, which has a detrimental effect on the surrounding plant species. Although, studies on catechin secretion and phytotoxicity represent one of the most well studied systems describing negative plant-plant interactions, it has also sparked controversies lately due to its phytotoxicity dosages and secretion effluxes. Previous reports negate the phytotoxic and pro-oxidant nature of catechin.1-3 In our recent study we have shown that catechin is highly phytotoxic against Arabidopsis thaliana and Festuca idahoensis. We also show that (±) catechin applied to roots of A. thaliana induces reactive oxygen species (ROS) confirming the pro-oxidant nature of catechin. In addition, activation of signature cell death genes such as acd2 and cad1 post catechin treatment in A. thaliana ascertains the phytotoxic nature of catechin.
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Affiliation(s)
- Harsh P Bais
- Department of Plant and Soil Sciences; University of Delaware; Newark, DE USA
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34
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Li ZH, Wang Q, Ruan X, Pan CD, Jiang DA. Phenolics and plant allelopathy. Molecules 2010; 15:8933-52. [PMID: 21139532 PMCID: PMC6259130 DOI: 10.3390/molecules15128933] [Citation(s) in RCA: 228] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Revised: 11/21/2010] [Accepted: 11/25/2010] [Indexed: 11/16/2022] Open
Abstract
Phenolic compounds arise from the shikimic and acetic acid (polyketide) metabolic pathways in plants. They are but one category of the many secondary metabolites implicated in plant allelopathy. Phenolic allelochemicals have been observed in both natural and managed ecosystems, where they cause a number of ecological and economic problems, such as declines in crop yield due to soil sickness, regeneration failure of natural forests, and replanting problems in orchards. Phenolic allelochemical structures and modes of action are diverse and may offer potential lead compounds for the development of future herbicides or pesticides. This article reviews allelopathic effects, analysis methods, and allelopathic mechanisms underlying the activity of plant phenolic compounds. Additionally, the currently debated topic in plant allelopathy of whether catechin and 8-hydroxyquinoline play an important role in Centaurea maculata and Centaurea diffusa invasion success is discussed. Overall, the main purpose of this review is to highlight the allelopacthic potential of phenolic compounds to provide us with methods to solve various ecology problems, especially in regard to the sustainable development of agriculture, forestry, nature resources and environment conservation.
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Affiliation(s)
- Zhao-Hui Li
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
- Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China
| | - Qiang Wang
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
- Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China
- Authors to whom correspondence should be addressed; E-Mails: (Q.W.); (D.-A.J.); Tel.: +86-574-88134338 (Q.W.); +86-571-88206461(D.-A.J.); Fax: +86-574-88229545 (Q.W.); +86-571-88206461(D.-A.J.)
| | - Xiao Ruan
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
- Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China
| | - Cun-De Pan
- College of Forest, Xinjiang Agricultural University, Urumqi 830052, China
| | - De-An Jiang
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
- Authors to whom correspondence should be addressed; E-Mails: (Q.W.); (D.-A.J.); Tel.: +86-574-88134338 (Q.W.); +86-571-88206461(D.-A.J.); Fax: +86-574-88229545 (Q.W.); +86-571-88206461(D.-A.J.)
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35
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Biogeographic differences in the effects of Centaurea stoebe on the soil nitrogen cycle: novel weapons and soil microbes. Biol Invasions 2010. [DOI: 10.1007/s10530-010-9902-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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36
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Knochel DG, Seastedt TR. Reconciling contradictory findings of herbivore impacts on spotted knapweed (Centaurea stoebe) growth and reproduction. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2010; 20:1903-1912. [PMID: 21049878 DOI: 10.1890/09-1944.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Substantial controversy surrounds the efficacy of biological control insects to reduce densities of Centaurea stoebe, a widespread, aggressive invasive plant in North America. We developed a graphical model to conceptualize the conditions required to explain the current contradictory findings, and then employed a series of manipulations to evaluate C. stoebe responses to herbivores. We manipulated soil nitrogen and competition in a field population and measured attack rates of a foliage and seed feeder (Larinus minutus), two gall flies (Urophora spp.), and a root feeder (Cyphocleonus achates), as well as their effects on the growth and reproduction of C. stoebe. Nitrogen limitation and competing vegetation greatly reduced C. stoebe growth. L. minutus most intensively reduced seed production in low-nitrogen soils, and removal of neighboring vegetation increased Larinus numbers per flower head and the percentage of flowers attacked by 15% and 11%, respectively. Cyphocleonus reduced flower production and aboveground biomass over two years, regardless of resources or competition. Our results, in conjunction with other published studies, demonstrate that positive, neutral, and negative plant growth responses to herbivory can be generated. However, under realistic field conditions and in the presence of multiple herbivores, our work repudiates earlier studies that indicate insect herbivores increase C. stoebe dominance.
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Affiliation(s)
- David G Knochel
- Department of Ecology and Evolutionary Biology, Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado 80309, USA.
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37
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May L, Baldwin LK. Linking field based studies with greenhouse experiments: the impact of Centaurea stoebe (=C. maculosa) in British Columbia grasslands. Biol Invasions 2010. [DOI: 10.1007/s10530-010-9879-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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38
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Bajpai D, Rajeswari MS. Interaction of 8-hydroxyquinoline with soil environment mediates its ecological function. PLoS One 2010; 5:e12852. [PMID: 20877629 PMCID: PMC2943481 DOI: 10.1371/journal.pone.0012852] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Accepted: 08/20/2010] [Indexed: 11/24/2022] Open
Abstract
Background Allelopathic functions of plant-released chemicals are often studied through growth bioassays assuming that these chemicals will directly impact plant growth. This overlooks the role of soil factors in mediating allelopathic activities of chemicals, particularly non-volatiles. Here we examined the allelopathic potential of 8-hydroxyquinoline (HQ), a chemical reported to be exuded from the roots of Centaurea diffusa. Methodology/Principal Findings Growth bioassays and HQ recovery experiments were performed in HQ-treated soils (non-sterile, sterile, organic matter-enriched and glucose-amended) and untreated control soil. Root growth of either Brassica campestris or Phalaris minor was not affected in HQ-treated non-sterile soil. Soil modifications (organic matter and glucose amendments) could not enhance the recovery of HQ in soil, which further supports the observation that HQ is not likely to be an allelopathic compound. Hydroxyquinoline-treated soil had lower values for the CO2 release compared to untreated non-sterile soil. Soil sterilization significantly influenced the organic matter content, PO4-P and total organic nitrogen levels. Conclusion/Significance Here, we concluded that evaluation of the effect of a chemical on plant growth is not enough in evaluating the ecological role of a chemical in plant-plant interactions. Interaction of the chemical with soil factors largely determines the impact of HQ on plant growth.
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Kaushik S, Bais HP, Biedrzycki ML, Venkatachalam L. Catechin is a phytototoxin and a pro-oxidant secreted from the roots of Centaurea stoebe. PLANT SIGNALING & BEHAVIOR 2010; 5:1088-98. [PMID: 20505358 PMCID: PMC3115074 DOI: 10.4161/psb.5.9.11823] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
When applied to the roots of Arabidopsis thaliana, the phytotoxin (±)-catechin triggers a wave of reactive oxygen species (ROS), leading to a cascade of genome-wide changes in gene expression and, ultimately, death of the root system. Biochemical links describing the root secreted phytotoxin, (±)-catechin, represent one of most well studied systems to describe biochemically based negative plant-plant interactions, but of late have also sparked controversies on phytotoxicity and pro-oxidant behavior of (±)-catechin. The studies originating from two labs ( 1- 3) maintained that (±)-catechin is not at all phytotoxic but has strong antioxidant activity. The step-wise experiments performed and the highly correlative results reported in the present study clearly indicate that (±)-catechin indeed is phytotoxic against A. thaliana and Festuca idahoensis. Our results show that catechin dissolved in both organic and aqueous phase inflict phytotoxic activity against both A. thaliana and F. idahoensis. We show that the deviation in results highlighted by the two labs ( 1- 3) could be due to different media conditions and a group effect in catechin treated seedlings. We also determined the presence of catechin in the growth medium of C. stoebe to support the previous studies. One of the largest functional categories observed for catechin-responsive genes corresponded to gene families known to participate in cell death and oxidative stress. Our results showed that (±)-catechin treatment to A. thaliana plants resulted in activation of signature cell death genes such as accelerated cell death (acd2) and constitutively activated cell death 1 (cad1). Further, we confirmed our earlier observation of (±)-catechin induced ROS mediated phytotoxicity in A. thaliana. We also provide evidence that (±)-catechin induced ROS could be aggravated in the presence of divalent transition metals. These observations have significant impact on our understanding regarding catechin phytotoxicity and pro-oxidant activity. Our data also illustrates that precise conditions are needed to evaluate the effect of catechin phytotoxicity.
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Affiliation(s)
- Shail Kaushik
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA
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40
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Impacts of soil microbial communities on exotic plant invasions. Trends Ecol Evol 2010; 25:512-9. [PMID: 20638747 DOI: 10.1016/j.tree.2010.06.006] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 06/12/2010] [Accepted: 06/14/2010] [Indexed: 11/20/2022]
Abstract
Soil communities can have profound effects on invasions of ecosystems by exotic plant species. We propose that there are three main pathways by which this can happen. First, plant-soil feedback interactions in the invaded range are neutral to positive, whereas native plants predominantly suffer from negative soil feedback effects. Second, exotic plants can manipulate local soil biota by enhancing pathogen levels or disrupting communities of root symbionts, while suffering less from this than native plants. Third, exotic plants produce allelochemicals toxic to native plants that cannot be detoxified by local soil communities, or that become more toxic following microbial conversion. We discuss the need for integrating these three pathways in order to further understand how soil communities influence exotic plant invasions.
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Does allelopathy explain the invasiveness of Campuloclinium macrocephalum (pompom weed) in the South African grassland biome? Biol Invasions 2010. [DOI: 10.1007/s10530-010-9747-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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42
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Bais HP, Venkatachalam L, Biedrzycki ML. Stimulation or Inhibition: Conflicting evidence for (+/-)-catechin's role as a chemical facilitator and disease protecting agent. PLANT SIGNALING & BEHAVIOR 2010; 5:239-246. [PMID: 20023372 PMCID: PMC2881267 DOI: 10.4161/psb.5.3.10573] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 11/09/2009] [Indexed: 05/28/2023]
Abstract
The occurrence of plant hormesis is a poorly understood phenomenon, wherein low doses of phytotoxins unusually promote growth responses in higher plants. In contrast, negative plant-plant interactions mediated through secreted small molecular weight compounds initiate growth inhibitory responses. Studies related to (+/-)-catechin mediated allelopathy have transpired both novel information and generated significant controversy. Specifically, studies related to the phytotoxicity responses mediated by (+/-)-catechins have been seriously debated. The pronged opinion that (+/-)-catechin is phytotoxic versus non-phytotoxic relies more on the target plant systems and the conditions used to test phytotoxic responses. It is reported that lower than MIC dosage supplementation of (+/-)-catechin could promote growth responses in the model plant Arabidopsis thaliana. Furthermore, it was shown that sub-MIC levels of (+/-)-catechin supplementation leads to elicitation of disease resistance against Pseudomonas syringae DC3000 (hereafter DC3000). Intrigued by the unique hormesis response observed, we tested whether (+/-)-catechin indeed promotes growth responses in A. thaliana. In our hands, we observed no growth promotion responses of (+/-)-catechin against A. thaliana under in vitro or in soil conditions. We also evaluated the previously reported disease protecting properties of (+/-)-catechin in A. thaliana against DC3000. The systematic observations to evaluate disease protecting properties entailing colony counts, disease incidences and loss of chlorophyll studies showed no disease protecting properties of (+/-)-catechin. The transcriptional response for a marker pathogenesis related PR1 defense gene showed no induction post (+/-)-catechin supplementation. The cell death genes (ACD2 and CAD1) associated with programmed cell death revealed unchanged expression levels in plants treated with sub-MIC levels of (+/-)-catechin. Further, we report supplementation of sub-MIC levels of (+/-)-catechin negates any change in the expression of an auxin responsive gene. Our results refute the previous claims of growth and defense inducing effects of (+/-)-catechin, thus suggesting that a thorough reexamination is required to evaluate the hormetic effect of (+/-)-catechin under both controlled and natural conditions.
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Affiliation(s)
- Harsh P Bais
- Department of Plant and Soil Sciences, University of Delaware, and Delaware Biotechnology Institute, Newark, DE, USA.
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43
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Weidenhamer JD, Callaway RM. Direct and indirect effects of invasive plants on soil chemistry and ecosystem function. J Chem Ecol 2010; 36:59-69. [PMID: 20077127 DOI: 10.1007/s10886-009-9735-0] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Revised: 12/10/2009] [Accepted: 12/15/2009] [Indexed: 10/20/2022]
Abstract
Invasive plants have a multitude of impacts on plant communities through their direct and indirect effects on soil chemistry and ecosystem function. For example, plants modify the soil environment through root exudates that affect soil structure, and mobilize and/or chelate nutrients. The long-term impact of litter and root exudates can modify soil nutrient pools, and there is evidence that invasive plant species may alter nutrient cycles differently from native species. The effects of plants on ecosystem biogeochemistry may be caused by differences in leaf tissue nutrient stoichiometry or secondary metabolites, although evidence for the importance of allelochemicals in driving these processes is lacking. Some invasive species may gain a competitive advantage through the release of compounds or combinations of compounds that are unique to the invaded community—the “novel weapons hypothesis.” Invasive plants also can exert profound impact on plant communities indirectly through the herbicides used to control them. Glyphosate, the most widely used herbicide in the world, often is used to help control invasive weeds, and generally is considered to have minimal environmental impacts. Most studies show little to no effect of glyphosate and other herbicides on soil microbial communities. However, herbicide applications can reduce or promote rhizobium nodulation and mycorrhiza formation. Herbicide drift can affect the growth of non-target plants, and glyphosate and other herbicides can impact significantly the secondary chemistry of plants at sublethal doses. In summary, the literature indicates that invasive species can alter the biogeochemistry of ecosystems, that secondary metabolites released by invasive species may play important roles in soil chemistry as well as plant-plant and plant-microbe interactions, and that the herbicides used to control invasive species can impact plant chemistry and ecosystems in ways that have yet to be fully explored.
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Orians CM, Ward D. Evolution of plant defenses in nonindigenous environments. ANNUAL REVIEW OF ENTOMOLOGY 2010; 55:439-459. [PMID: 19737084 DOI: 10.1146/annurev-ento-112408-085333] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Exotic plants provide a unique opportunity to explore the evolution of defense allocation in plants. Many studies have focused on whether enemy release leads to a change in defense allocation. Little research has focused on induced defenses and on how resource availability in the nonindigenous range might cause evolutionary shifts in defense trait allocation. We examine (a) the major evolutionary hypotheses predicting defense expression in plants, (b) the hypotheses explaining defense evolution of exotic species, and (c) the importance of geographic variation in ecological interactions to defense evolution (geographic mosaics). In addition, we review the strengths and weaknesses of experimental approaches, present case studies, and suggest areas that deserve further attention.
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Affiliation(s)
- Colin M Orians
- Department of Biology, Tufts University, Medford, Massachusetts 02155, USA.
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Chobot V, Hadacek F. Iron and its complexation by phenolic cellular metabolites: from oxidative stress to chemical weapons. PLANT SIGNALING & BEHAVIOR 2010; 5:4-8. [PMID: 20592800 PMCID: PMC2835949 DOI: 10.4161/psb.5.1.10197] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2009] [Accepted: 09/28/2009] [Indexed: 05/20/2023]
Abstract
Iron is a transition metal that forms chelates and complexes with various organic compounds, also with phenolic plant secondary metabolites. The ligands of iron affect the redox potential of iron. Electrons may be transferred either to hydroxyl radicals, hydrogen peroxide or molecular oxygen. In the first case, oxidative stress is decreased, in the latter two cases, oxidative stress is increased. This milieu-dependent mode of action may explain the non-linear mode of action of juglone and other secondary metabolites. Attention to this phenomenon may help to explain idiosyncratic and often nonlinear effects that result in biological assays. Current chemical assays are discussed that help to explore these aspects of redox chemistry.
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Affiliation(s)
- Vladimir Chobot
- Department of Chemical Ecology and Ecosystem Research, Faculty of Life Sciences, University of Vienna, Vienna, Austria
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Soil degradation of parthenin-does it contradict the role of allelopathy in the invasive weed Parthenium hysterophorus L.? J Chem Ecol 2009; 35:1137-50. [PMID: 19795173 DOI: 10.1007/s10886-009-9698-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 09/15/2009] [Accepted: 09/21/2009] [Indexed: 10/20/2022]
Abstract
The invasive success of Parthenium hysterophorus L. is thought to be partially attributable to allelopathy mediated by the plant metabolite parthenin. To assess the ecological significance of parthenin release from plant material, its persistence and phytotoxicity in soil was studied. Results show parthenin is rapidly degraded with an average DT (50) of 59 h under standard experimental conditions. Degradation was delayed in sterilized soils, at lower soil moisture, and higher parthenin concentrations. Higher temperatures, higher CEC(pot)/clay content of soils, soil preconditioning with parthenin, and P. hysterophorus infestation accelerated degradation. Physico-chemical and biological processes are, therefore, expected to govern the fate of parthenin in soil. Parthenin exhibited low soil phytotoxicity and did not accumulate over time. Along with the indicated reduction in bioavailability and development of hormetic effects, results suggest that for parthenin to have detrimental allelopathic effects, it requires high P. hysterophorus densities that result in high soil levels of parthenin and soil conditions that favor the persistence of parthenin. In light of this, the ecological significance of parthenin is discussed.
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Blair AC, Hufbauer RA. Hybridization and invasion: one of North America's most devastating invasive plants shows evidence for a history of interspecific hybridization. Evol Appl 2009; 3:40-51. [PMID: 25567902 PMCID: PMC3352454 DOI: 10.1111/j.1752-4571.2009.00097.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 07/28/2009] [Indexed: 11/27/2022] Open
Abstract
Hybridization has been hypothesized to influence invasion through the generation of novel phenotypes and/or increased levels of genetic variance. Based on morphology, hybrids between diffuse knapweed and spotted knapweed, two invasive plants in North America, are present in the invaded range. Some individuals within most diffuse knapweed sites in North America exhibit intermediate diffuse × spotted floral morphology. We examined hybridization at the molecular level, using amplified fragment length polymorphisms. Approximately a quarter of the assayed North American diffuse knapweed individuals exhibited evidence of introgression from spotted knapweed. However, plants with intermediate morphology did not show evidence of mixed ancestry more often than the plants with typical diffuse knapweed morphology. The high proportion of hybrid individuals in North American diffuse knapweed sites found here, combined with evidence from recent studies, suggests that diffuse knapweed was likely introduced with admixed individuals, and the hybrids are not newly created postintroduction. A century of backcrossing with diffuse knapweed has likely decoupled the relationship between morphology and admixture at the molecular level. In contrast to the scenario encountered in North America, in the native range where diploid diffuse and spotted knapweed overlap, hybrid swarms are common. In such sites, the floral phenotype aligns more closely with the genotype.
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Affiliation(s)
- Amy C Blair
- Graduate Degree Program in Ecology and Department of Bioagricultural Sciences and Pest Management, Colorado State University Fort Collins, CO, USA
| | - Ruth A Hufbauer
- Graduate Degree Program in Ecology and Department of Bioagricultural Sciences and Pest Management, Colorado State University Fort Collins, CO, USA ; Centre de Biologie et Gestion des Populations Campus International de Baillarguet CS 30016, Montferrier-sur-Lez cedex, France
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Chobot V, Huber C, Trettenhahn G, Hadacek F. (+/-)-catechin: chemical weapon, antioxidant, or stress regulator? J Chem Ecol 2009; 35:980-96. [PMID: 19701725 PMCID: PMC2746304 DOI: 10.1007/s10886-009-9681-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 07/23/2009] [Accepted: 08/06/2009] [Indexed: 01/23/2023]
Abstract
(+/-)-Catechin is a flavan-3-ol that occurs in the organs of many plant species, especially fruits. Health-beneficial effects have been studied extensively, and notable toxic effects have not been found. In contrast, (+/-)-catechin has been implicated as a 'chemical weapon' that is exuded by the roots of Centaurea stoebe, an invasive knapweed of northern America. Recently, this hypothesis has been rejected based on (+/-)-catechin's low phytotoxicity, instability at pH levels higher than 5, and poor recovery from soil. In the current study, (+/-)-catechin did not inhibit the development of white and black mustard to an extent that was comparable to the highly phytotoxic juglone, a naphthoquinone that is allegedly responsible for the allelopathy of the walnut tree. At high stress levels, caused by sub-lethal methanol concentrations in the medium, and a 12 h photoperiod, (+/-)-catechin even attenuated growth retardation. A similar effect was observed when (+/-)-catechin was assayed for brine shrimp mortality. Higher concentrations reduced the mortality caused by toxic concentrations of methanol. Further, when (+/-)-catechin was tested in variants of the deoxyribose degradation assay, it was an efficient scavenger of reactive oxygen species (ROS) when they were present in higher concentrations. This antioxidant effect was enhanced when iron was chelated directly by (+/-)-catechin. Conversely, if iron was chelated to EDTA, pro-oxidative effects were demonstrated at higher concentrations; in this case (+/-)-catechin reduced molecular oxygen and iron to reagents required by the Fenton reaction to produce hydroxyl radicals. A comparison of cyclic voltammograms of (+/-)-catechin with the phytotoxic naphthoquinone juglone indicated similar redox-cycling properties for both compounds although juglone required lower electrochemical potentials to enter redox reactions. In buffer solutions, (+/-)-catechin remained stable at pH 3.6 (vacuole) and decomposed at pH 7.4 (cytoplasm) after 24 h. The results support the recent rejection of the hypothesis that (+/-)-catechin may serve as a 'chemical weapon' for invasive plants. Instead, accumulation and exudation of (+/-)-catechin may help plants survive periods of stress.
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Affiliation(s)
- Vladimir Chobot
- Department of Chemical Ecology and Ecosystem Research, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria
| | - Christoph Huber
- Department of Physical Chemistry, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Guenter Trettenhahn
- Department of Physical Chemistry, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Franz Hadacek
- Department of Chemical Ecology and Ecosystem Research, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria
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Tharayil N. To survive or to slay: Resource-foraging role of metabolites implicated in allelopathy. PLANT SIGNALING & BEHAVIOR 2009; 4:580-3. [PMID: 19820349 PMCID: PMC2710547 DOI: 10.4161/psb.4.7.8915] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The ecological relevance of allelopathy is highly debated due to the lack of phytotoxic concentrations of allelochemical in natural field conditions. Most of the putative allelochemicals are exuded at low concentrations, and subsequently undergo rapid chemical and biological degradation in soil matrices. At sub-toxic concentrations, due to hormesis effect, these compounds could possibly have a stimulatory effect on plant growth. Many of the suggested allelopathic compounds are chelants and can complex-with and mobilize metal ions in soil. These complexation reactions will detoxify the compound, but will increase the chemical-nutrient-foraging ability of the donor plant. The concentration in which these compounds are exuded matches with other similar secondary metabolites facilitating plant nutrient acquisition. Irrespective of whether the implicated PSMs facilitate donor plant in chemical nutrient-foraging or in poisoning the neighbors, the conferred advantage translates in terms of resource availability-in first case the donor enjoys uncontested nutrient uptake efficiency, where as in the latter the donor gain an uncontested access to resources. This further reaffirms the notion that resource competition and allelopathy are inextricable. Since most of the secondary metabolites could mobilize nutrients from soil, along with its phytotoxic effect, complementary self-facilitation roles of these compounds should be investigated.
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Affiliation(s)
- Nishanth Tharayil
- Entomology, Soils & Plant Sciences, Clemson University, Clemson, SC 29634, USA.
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Duke SO, Dayan FE, Bajsa J, Meepagala KM, Hufbauer RA, Blair AC. The case against (-)-catechin involvement in allelopathy of Centaurea stoebe (spotted knapweed). PLANT SIGNALING & BEHAVIOR 2009; 4:422-424. [PMID: 19816095 PMCID: PMC2676754 DOI: 10.4161/psb.4.5.8273] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Accepted: 02/25/2009] [Indexed: 05/28/2023]
Abstract
Proving allelopathic chemical interference is a daunting endeavor, in that production and movement of a phytotoxin from a donor plant to a receiving plant must be demonstrated in the substrate in which the plants grow, which is usually a complex soil matrix. The soil levels or soil flux levels of the compound generated by the donor must be proven to be sufficient to adversely affect the receiving plant. Reports of (-)-catechin to be the novel weapon used by Centaurea stoebe (spotted knapweed) to invade new territories are not supported by the paper featured in this Addendum, nor by papers produced by two other laboratories. These papers find that (-)-catechin levels in soil in which C. stoebe grows are orders of magnitude below levels that cause only minor growth effects on reported sensitive species. Furthermore, the claim that (-)-catechin acts as a phytotoxin through causing oxidative damage is refuted by the fact that the molecule is a strong antioxidant and is quickly degraded by extracellular root enzymes.
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Affiliation(s)
- Stephen O Duke
- Natural Products Utilization Research Unit, Agricultural Research Service, United States Department of Agriculture, Oxford, MI, USA.
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