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1.
Int J Mol Sci ; 22(15)2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34360628

RESUMO

Macroalgae are the source of many harmful allelopathic compounds, which are synthesized as a defense strategy against competitors and herbivores. Therefore, it can be predicted that certain species reduce aquaculture performance. Herein, the allelopathic ability of 123 different taxa of green, red, and brown algae have been summarized based on literature reports. Research on macroalgae and their allelopathic effects on other animal organisms was conducted primarily in Australia, Mexico, and the United States. Nevertheless, there are also several scientific reports in this field from South America and Asia; the study areas in the latter continents coincide with areas where aquaculture is highly developed and widely practiced. Therefore, the allelopathic activity of macroalgae on coexisting animals is an issue that is worth careful investigation. In this work, we characterize the distribution of allelopathic macroalgae and compare them with aquaculture locations, describe the methods for the study of macroalgal allelopathy, present the taxonomic position of allelopathic macroalgae and their impact on coexisting aquatic competitors (Cnidaria) and herbivores (Annelida, Echinodermata, Arthropoda, Mollusca, and Chordata), and compile information on allelopathic compounds produced by different macroalgae species. This work gathers the current knowledge on the phenomenon of macroalgal allelopathy and their allelochemicals affecting aquatic animal (competitors and predators) worldwide and it provides future research directions for this topic.


Assuntos
Alelopatia , Aquicultura , Invertebrados , Defesa das Plantas contra Herbivoria , Alga Marinha/metabolismo , Animais , Herbivoria , Alga Marinha/genética
2.
Harmful Algae ; 107: 102069, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34456024

RESUMO

In 2006, species of Cochlodinium geminatum were first recorded as new, harmful algal bloom (HAB)-forming dinoflagellate, in the Pearl River Estuary, China. Previous studies indicated that allelopathy (the release of chemical compounds) is an important competitive strategy for C. geminatum in inhibiting the growth of phytoplankton competitors, however, little is known about the allelochemicals produced by this species. In this study, allelopathic compounds were characterized using a series of chromatographic techniques. Methanol extracts from cultures showed significant inhibitory effects towards the co-occurring phytoplankton, Akashiwo sanguinea, and potent hemolytic activity against rabbit erythrocytes. Solid phase extraction (SPE) fractions from a reverse phase SPE column, exhibited inhibitory and synergistic effects on A. sanguinea growth, of which fractions eluted in 80% and 100% methanol showed the strongest allelopathic activity. These fractions were further purified using reverse phase high performance liquid chromatography (HPLC), and six fractions were collected. Three fractions displayed strong inhibitory effects towards A. sanguinea, with 14%-25% inhibitory rates, but a higher 35% inhibitory rate was observed when fractions were combined, suggesting allelochemicals had synergistic allelopathic effects. Allelopathic activity also exhibited time dependent reduction when stored at -20°C. Furthermore, trypsin digestion and dialysis assays indicated C. geminatum produced multiple allelopathic compounds. Our study demonstrated that species of C. geminatum produced and released multiple allelopathic compounds of low polarity and sufficient hydrophilicity, which elicit important competitive advantages by inhibiting co-occurring phytoplankton, and promoting population growth.


Assuntos
Dinoflagelados , Alelopatia , Animais , Estuários , Proliferação Nociva de Algas , Fitoplâncton , Coelhos
3.
Pestic Biochem Physiol ; 177: 104897, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34301359

RESUMO

To seek novel and safe protoporphyrinogen oxidase (PPO, EC 1.3.3.4) inhibitors with excellent herbicidal activity. A series of novel phenoxypyridine derivatives containing natural product coumarins with allelopathy were designed and synthesized based on bioisosterism and active subunit combination in this research. Compounds W3.1 and W3.4, with the half-maximal inhibitory concentration (IC50) value of 0.02653 mg/L and 0.01937 mg/L, respectively, displayed excellent herbicidal activity in greenhouse. Their herbicidal activity was similar to commercial herbicide oxyfluorfen (IC50 = 0.04943 mg/L). The best field inhibitory effect of compounds W3.1 and W3.4 recorded was at doses of 450 g ai/ha and 300 g ai/ha, respectively. Compound W3.4 had the best herbicidal activity among all the target compounds in this paper. Molecular docking analysis revealed that compounds W3.1 and W3.4 could form a hydrogen bonds with the amino acid AGR-98 and a π-π superposition with the amino acid PHE-398, respectively, which was similar to the oxyfluorfen. The crop selectivity tests results indicated that maize, cotton and soybean showed high tolerance to compound W3.4. Compound W3.4 reduced the Ca and Cb contents of wheat and rice, but had less effect on maize, cotton and soybean. Selectivity of compound W3.4 in maize, cotton and soybean were appeared to be due to reduced absorption of the herbicide compared to wheat and rice. Compound W3.4 deserves further attention as a candidate structure for new herbicides.


Assuntos
Produtos Biológicos , Herbicidas , Alelopatia , Cumarínicos/farmacologia , Inibidores Enzimáticos/farmacologia , Herbicidas/toxicidade , Simulação de Acoplamento Molecular , Oxirredutases , Plantas Daninhas , Relação Estrutura-Atividade
4.
Mar Pollut Bull ; 170: 112673, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34225191

RESUMO

In this study, we aim to explore the allelochemicals of marine brown algae Sargassum fusiforme and the mechanism of allelopathy effect on Heterosigma akashiwo. Six potential allelopathic substances, palmitic acid, arachidonic acid, α-linolenic acid (ALA), fucosterol, 24-hydroperoxy-24-vinylcholesterol, and saringosterowere, were isolated and identified from S. fusiforme by column chromatography, NMR, TOF-MS and GC-MS analyses. The ALA and 24-hydroperoxy-24-vinylcholesterol showed remarkable inhibitory activities on H. akashiwo growth. Besides, the allelopathic mechanism between the ALA and H. akashiwo was preliminarily investigated. The results indicated that the activities of SOD and POD of H. akashiwo gradually decreased under high ALA concentration. The reduction of photosynthetic pigments and chlorophyll fluorescence parameters, as well as apparent electron transport rate in H. akashiwo cells, aggravated gradually with increasing the concentration of the ALA. In summary, this study revealed the responses of morphology and physiology of H. akashiwo when exposed by ALA, while revealing the potential of macroalgae in red tide control.


Assuntos
Microalgas , Sargassum , Alelopatia , Proliferação Nociva de Algas , Feromônios
5.
Phytochemistry ; 189: 112826, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34102592

RESUMO

Chemical interactions between macroalgae and other organisms play an important role in determining species compositions and dominance patterns, and can explain the widespread success of some species in establishing their predominant populations in a specific coastal area. Allelopathy could act as a self-regulatory strategy of the algal community, being not only a succession regulator but also an active mechanism maintaining the species diversity especially in a delimited environment, such as the benthic ecosystem. Polyunsaturated aldehydes (PUAs) are among the most studied allelopathic compounds and are commonly released into the aquatic environment by different phytoplankton species in response to environmental stressors (e.g. wounding, grazing, or competition for nutrients). Diatom-released PUAs were observed to affect phytoplankton community dynamics and structure, and showed inhibitory effects on the reproduction and development of marine invertebrates. As for macroalgae, there are only a few reports that attest to the production of PUAs, and mostly refer to Ulva spp. In this study, the production of PUAs by several Mediterranean macroalgae was investigated at different sampling times, aiming at providing the first evidence of potential allelochemical activity. Results highlighted the potential production by macroalgae of a variety of aldehydes, among which some have never reported so far. Some species (i.e. D. polypodioides and U. cf. rigida) were found to produce higher PUAs amounts than others, and even a wider variety of structures (e.g. length of the carbon chain); these species might exert strong effects on epiphytic species or other organisms of the benthic community, especially considering the differential sensitivities of the various taxa. A high dPUA concentration (order of µM) potentially due to the release of PUAs by algal species was found, and might affect the population dynamics of the epiphytic organisms (e.g. microalgae, meiofauna), of grazers, as well as of the microbial community.


Assuntos
Diatomáceas , Alga Marinha , Aldeídos , Alelopatia , Ecossistema , Fitoplâncton
6.
Aquat Toxicol ; 237: 105878, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34102539

RESUMO

Interactions between Scrippsiella acuminata and three diatoms, Chaetoceros curvisetus, Phaeodactylum tricornutum, and Skeletonema dohrnii, were investigated using bi-algal co-cultures and cell-free and sonicated-cell filtrates in this study. Volatile aldehydes in sonicated filtrates of the three diatoms were analyzed by GC/MS. Furthermore, effects of 2E, 4E-decadienal (2,4-D) on the growth and the photosynthetic efficiency of the four microalgal species were studied. The growth of Sc. acuminata was significantly inhibited by the three diatoms in all co-cultures, and the inhibitory effects were higher under nutrient-rich conditions. Both cell-free and sonicated-cell filtrates of the three diatoms showed significant inhibitions on the growth of Sc. acuminata, which highlighted that diatoms produce allelopathic compounds not only to the surrounding environments but also inside the cells. Fifteen aldehydes were detected in the sonicated-cell filtrates of the three diatoms, and 5, 5, and 12 types of aldehydes were detected in C. curvisetus, P. tricornutum, and Sk. dohrnii, respectively. Polyunsaturated aldehydes (PUAs) composition differed among the three diatom species. Phenylglyoxal (C8H6O2) dominated in C. curvisetus, 2,4-D (C10H16O) predominated in P. tricornutum, and high proportions of 2-hexenal (C6H10O), 2E, 4E-heptadienal (C7H10O), and 2,4-D were detected in Sk. dohrnii. 2,4-D showed significantly inhibitory effects on the growth of algal cells including diatoms themselves in a dose-dependent manner, and photosynthetic efficiency was significantly decreased as well. Sc. acuminata was the most sensitive species. The 96 h EC50 values of 2,4-D on the growth of the four microalgae were 1.64 µmol/L for Sc. acuminata, 3.09 µmol/L for C. curvisetus, 4.93 µmol/L for P. tricornutum, and 8.54 µmol/L for Sk. dohrnii, respectively. The results suggest that PUAs produced by diatoms may help them to take the competitive advantages in phytoplankton community, and thus to sustain diatom-dominated community structure in nutrient rich coastal waters.


Assuntos
Diatomáceas , Dinoflagelados , Poluentes Químicos da Água , Alelopatia , Fitoplâncton , Poluentes Químicos da Água/toxicidade
7.
Nat Plants ; 7(6): 725-729, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34099902

RESUMO

Recent carbon dioxide (CO2) concentrations promoted higher parthenin concentrations in an invasive Parthenium hysterophorus biotype. Mean concentrations of parthenin, an allelopathic and defensive sesquiterpene lactone, were 49% higher at recent (~400 ppm) than at mid-twentieth-century (~300 ppm) CO2 concentrations, but did not vary in a non-invasive biotype, suggesting that recent increases in atmospheric CO2 may have already altered the chemistry of this destructive weed, potentially contributing to its invasive success.


Assuntos
Asteraceae/metabolismo , Dióxido de Carbono , Plantas Daninhas/metabolismo , Sesquiterpenos/metabolismo , Alelopatia , Asteraceae/fisiologia , Ecótipo , Espécies Introduzidas , Brotos de Planta/metabolismo , Plantas Daninhas/fisiologia , Toxinas Biológicas/metabolismo
8.
Am J Bot ; 108(6): 971-979, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34121189

RESUMO

PREMISE: Invasion processes involve several mechanisms, some of which have received little attention. Allelopathy has been invoked as an invasion driver according to the novel weapon hypothesis (NWH), and polyploidization can also be an important factor for invasion success. However, very few studies have addressed both topics together. We analyzed the allelopathic effect of the polyploid Oxalis pes-caprae, an invader in mediterranean-climate areas worldwide, from different origins and ploidy levels (native: South Africa; invaded: Chile, Australia, California, and the Mediterranean Basin) on Lactuca sativa as a model species. METHODS: We measured seed germination, initial plant height, and aboveground and belowground biomass of Lactuca grown in field soil mixed with Oxalis material and with or without activated carbon in a common garden experiment. We performed the experiment twice, when Oxalis was vigorous and when senescent. RESULTS: Vigorous plants of Oxalis tended to reduce Lactuca germination, but both vigorous and senescent Oxalis plants increased Lactuca biomass, probably due to an increase in nutrients provided by plant material. The highest increase in Lactuca traits occurred with Oxalis plants from the Iberian Peninsula. Allelopathy only happened when Oxalis was senescent and was especially strong with plants from Chile. CONCLUSIONS: Although we did not find broad evidence for the NWH considering all areas together, we reported differences in the allelopathic potential of Oxalis plants depending on their origin. These results highlight the independent evolution of invasiveness traits in distant introduced ranges and the importance of the invaders' origin when testing hypotheses about invasion drivers.


Assuntos
Espécies Introduzidas , Oxalidaceae , Alelopatia , Austrália , Chile , Europa (Continente) , África do Sul
9.
Braz J Biol ; 82: e235475, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34105661

RESUMO

Plants that produce secondary metabolites with allelopathic activity or phytotoxicity can be biotechnologically important, serving as sources of allelochemicals, and thus contributing to the agroindustrial sector. Vismia japurensis (Hypericaceae) is an Amazonian species that grows in clumps called vismiais, from which most other plants are absent. Accordingly, the objective of this study was to identify possible phytotoxicity effects of hexane and methanol extracts of Vismia japurensis leaves and branches in vivo and from seedlings grown in vitro on Lactuca sativa. In addition, fresh and dry leaves were assayed by the sandwich method in order to determine their ability to release allelochemicals. The hexanic extract from in vitro seedlings reduced germination by 10%, while the methanol extract produced a 16% reduction in germination speed. Root growth of Lactuca sativa was inhibited by 64.7% when subjected to hexane leaf extract, by 39.3% under the influence of hexane branch extract, and by 96.09% for in vitro seedling hexanic extract. When analysed by thin layer chromatography and 1H nuclear magnetic resonance, extracts showed evidence of terpenes, anthraquinones and flavonoids, with greater intensity of signals in the aromatic region of in vitro seedling hexanic extract. Clearly, Vismia japurensis has a high biotechnological potential in terms of the production of substances of low polarity with capacity to interfere in plant development.


Assuntos
Clusiaceae , Germinação , Alelopatia , Extratos Vegetais/toxicidade , Folhas de Planta , Plântula
10.
Chem Biodivers ; 18(7): e2100238, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34033700

RESUMO

Plants belonging to Euphorbia L. genus are considered very interesting from a medicinal point of view due to their diverse metabolites and bioactivities. The essential oil (EO) of Euphorbia mauritanica L. is not studied up to date. Therefore, the present study aimed to explore the chemical profile of this EO and evaluate its antioxidant, cytotoxic, and allelopathic potentialities. The EO was extracted from the whole plant via hydrodistillation and then, analyzed by gas chromatography/mass spectrometry (GC/MS). The correlation of E. mauritanica with the other Euphorbia plants was established using chemometric analysis. The antioxidant activity was determined based on scavenging of the free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The anti-proliferation of the EO on the Hep G2 and MCF-7 cells was evaluated. Finally the allelopathic activity of the EO was assessed against the two noxious weeds, Dactyloctenium aegyptium and Urospermum picroides. Forty-one compounds were identified using GC/MS analysis, with an abundance of terpenoids (91.54 %) that were categorized into mono- (30.75 %), sesqui- (15.23 %), and diterpenes (45.56 %). Interestingly, the results revealed the preponderance of diterpenoid constituents although they are rarely found in the EOs of the plant kingdom. The major compounds were (3E)-cembrene A (18.66 %), verticiol (17.05 %), limonene (7.91 %), eucalyptol (7.26 %), α-pinene (5.61 %), neo-cembrene A (3.52 %), kaur-16-ene (3.24 %), and cembrene (3.09 %). The EO showed moderate antioxidant activity where it attained IC50 values of 83.34 and 64.21 µg mL-1 for DPPH and ABTS compared to 23.01 and 19.23 µg mL-1 for ascorbic acid as standard, respectively. The EO exhibited very weak cytotoxic effect on MCF-7 and Hep G2 cells. The EO showed significant allelopathic activities against the weeds D. aegyptium and U. picroides in a concentration-dependent manner. EO was found more effective against U. picroides than D. aegyptium with IC50 values of 0.79, 0.45, and 0.67 mg mL-1 and 1.17, 0.55, and 1.08 mg mL-1 for germination, root, and shoot growth, respectively. Due to the high content of diterpenes in E. mauritanica, further study is recommended for more characterization of pure forms of the identified diterpenes as well as evaluating their bioactivity either solely or synergistically.


Assuntos
Alelopatia/efeitos dos fármacos , Antineoplásicos Fitogênicos/farmacologia , Antioxidantes/farmacologia , Diterpenos/farmacologia , Euphorbia/química , Óleos Voláteis/química , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Antioxidantes/química , Antioxidantes/isolamento & purificação , Benzotiazóis/antagonistas & inibidores , Compostos de Bifenilo/antagonistas & inibidores , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Diterpenos/química , Diterpenos/isolamento & purificação , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Picratos/antagonistas & inibidores , Ácidos Sulfônicos/antagonistas & inibidores , Células Tumorais Cultivadas
11.
Sci Total Environ ; 773: 145681, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33940759

RESUMO

Allelopathy is widespread in marine, brackish, and freshwater habitats. Literature data indicate that allelopathy could offer a competitive advantage for some phytoplankton species by reducing the growth of competitors. It is also believed that allelopathy may affect species succession. Thus, allelopathy may play a role in the development of blooms. Over the past few decades, the world's coastal waters have experienced increases in the numbers of cyanobacterial and microalgal blooming events. Understanding how allelopathy is implicated with other biological and environmental factors as a bloom-development mechanism is an important topic for future research. This review focuses on a taxonomic overview of allelopathic cyanobacteria and microalgae, the biological and environmental factors that affect allelochemical production, their role in ecological dynamics, and their physiological modes of action, as well as potential industrial applications of allelopathic compounds.


Assuntos
Cianobactérias , Fitoplâncton , Alelopatia , Ecossistema , Feromônios/toxicidade
12.
Environ Sci Pollut Res Int ; 28(33): 45714-45723, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33877523

RESUMO

Green tides have been increasing in frequency and severity in coastal areas in recent years, and thus, the adverse effects of green tides on the environment have attracted much research attention. Allelopathy is one of the most significant effects of green tide algae on the surrounding organisms. In this study, a series of experiments were developed to fully investigate the allelopathic effects of the green tide alga Ulva linza on two common coastal phytoplankton species and to isolate and identify the chemical compositions of the allelochemicals. Our results indicated that the fresh tissue, dry powder, and aqueous extracts all inhibited the population growth of the two experimental phytoplankton species, indicating the occurrence of allelopathy; further analysis of the allelochemicals identified multiple kinds of fatty acids as allelopathic compounds, in which the most abundant ones were hexadecanoic acid; 9Z, 12Z, 15Z-octadecatetrienoic acid; and 9E-octadecenoic acid. Our findings enrich the database for research on allelopathy between marine green tide algae and phytoplankton. Both algae and phytoplankton could increase their own competitive abilities during bloom formation, thereby changing the phytoplankton community structure.


Assuntos
Fitoplâncton , Ulva , Alelopatia , Feromônios/farmacologia
13.
Am J Bot ; 108(4): 607-615, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33860930

RESUMO

PREMISE: Sparse understory communities, in association with non-native tree species, are often attributed to allelopathy, the chemical inhibition of a plant by another. However, allelopathy is a difficult ecological phenomenon to demonstrate as many studies show conflicting results. Eucalyptus globulus, a tree native to Australia, is one of the most widely planted trees around the world. Sparse understories are common beneath E. globulus plantations and are often attributed to allelopathy, but the ecological impacts of E. globulus on native plant communities outside Austrialia are poorly understood. METHODS: To assess allelopathy as a mechanism of understory inhibition, we tested volatile- and water-soluble leaf extracts from E. globulus, Salvia apiana, and Quercus agrifolia on seed germination of California native plants. We also quantified germination rates and early seedling growth of California native plants grown in soil from E. globulus plantations versus soil from an adjacent native plant community. RESULTS: Volatile compounds from E. globulus did not significantly reduce germination for any species. Inhibition from water-soluble E. globulus compounds was comparable to that of a native tree, Quercus agrifolia (10%). Eucalyptus globulus soil supported germination and early seedling growth of native species equal to or better than coastal scrub soil, although species responses were variable. CONCLUSIONS: In contrast to previous studies, our results fail to support the hypothesis that E. globulus chemically inhibits germination of native species. California native plants germinate and grow well in soils from E. globulus plantations, which may have significant implications for management and restoration of land historically occupied by E. globulus plantations.


Assuntos
Eucalyptus , Alelopatia , Austrália , Solo , Árvores
14.
An Acad Bras Cienc ; 93(1): e20200129, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33852715

RESUMO

Eragrostis plana (Nees) (Tough Lovegrass) shows ability to interfere with other plants, a phenomenon known as allelopathy. This chemical interaction between plants occurs due to the release of compounds into the environment. Thus, a phytotoxicity study was carried out with E. plana roots collected during each season throughout the year, and the compounds were extracted with solvents of increasing polarity. The data from the bioassays were analyzed by GLM and PCA. In addition, a fingerprint of these extracts was obtained by HPLC-DAD. The extracts in petroleum ether from roots collected in the winter and summer showed greater phytotoxicity on Ipomoea grandifolia germination and growth. The PCA obtained from the chromatogram of the crude extract showed that the extracts in petroleum ether were chemically different from the extracts in ethyl acetate and methanol. Thus, continuing this study in order to develop a new generation of bio-herbicides is essential.


Assuntos
Eragrostis , Alelopatia , Bioensaio , Cromatografia Líquida de Alta Pressão , Extratos Vegetais/toxicidade , Raízes de Plantas
15.
Sci Total Environ ; 780: 146484, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33774286

RESUMO

The dinoflagellate genus Alexandrium has been well known for causing paralytic shellfish poisoning (PSP) worldwide. Several non-PSP toxin-producing species, however, have shown to exhibit fish-killing toxicity. Here, we report the allelopathic activity of Alexandrium leei from Malaysia to other algal species, and its toxicity to finfish and zooplankton, via laboratory bioassays. Thirteen microalgal species that co-cultured with Al. leei revealed large variability in the allelopathic effects of Al. leei on the test algae, with the growth inhibition rates ranging from 0 to 100%. The negative allelopathic effects of Al. leei on microalgae included loss of flagella and thus the motility, damages of chain structure, deformation in cell morphology, and eventually cell lysis. The finfish experienced 100% mortality within 24 h exposed to the live culture (2000-6710 cells·mL-1), while the rotifer and brine shrimp exhibited 96-100% and 90-100% mortalities within 48 h when exposed to 500-6000 cells·mL-1 of Al. leei. The mortality of the test animals depended on the Al. leei cell density exposed, leading to a linear relationship between mortality and cell density for the finfish, and a logarithmic relationship for the two zooplankters. When exposed to the treatments using Al. leei whole live culture, cell-free culture medium, extract of algal cells in the f/2-Si medium, extract of methanol, and the re-suspended freeze-and-thaw algal cells, the test organisms (Ak. sanguinea and rotifers) all died at the cell density of 8100 cells·mL-1 within 24 h. Toxin analyses by HILIC-ESI-TOF/MS and LC-ESI-MS/MS demonstrated that Al. leei did not produce PSP-toxins and 13-desmethyl spirolide C. Overall, our findings demonstrated potent allelopathy and toxicity of Al. leei, which do not only pose threats to the aquaculture industry, fisheries, and marine ecosystems but may also play a part role in the population dynamics and bloom formation of this species.


Assuntos
Dinoflagelados , Alelopatia , Animais , Bioensaio , Ecossistema , Laboratórios , Malásia , Fitoplâncton , Espectrometria de Massas em Tandem , Zooplâncton
16.
J Exp Bot ; 72(11): 4022-4037, 2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-33647935

RESUMO

In the struggle to secure nutrient access and to outperform competitors, some plant species have evolved a biochemical arsenal with which they inhibit the growth or development of neighbouring plants. This process, known as allelopathy, exists in many of today's major crops, including rice. Rice synthesizes momilactones, diterpenoids that are released into the rhizosphere and inhibit the growth of numerous plant species. While the allelopathic potential of rice was recognized decades ago, many questions remain unresolved regarding the biosynthesis, exudation, and biological activity of momilactones. Here, we review current knowledge on momilactones, their role in allelopathy, and their potential to serve as a basis for sustainable weed management. We emphasize the gaps in our current understanding of when and how momilactones are produced and of how they act in plant cells, and outline what we consider the next steps in momilactone and rice allelopathy research.


Assuntos
Diterpenos , Oryza , Alelopatia , Lactonas , Rizosfera
17.
Sci Rep ; 11(1): 7068, 2021 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-33782496

RESUMO

Although it is well-documented that invasion of invasive plants is promoted with allelopathic effects by inhibiting the growth and phenotypic performance of native plants, little is known conversely. In this study, the allelopathy effects of a native plant, Humulus scandens (Lour.) Merr., on a typical invasive species Alternanthera philoxeroides (Mart.) Griseb., was investigated by exposing A. philoxeroides seedlings to three chemical solvent extracts (i.e., petroleum ether extract (PE), ethyl acetate extract (EE), and n-butanol extract (NE) of H. scandens root (HR). The three chemical extracts inhibited the growth, stem length, node number, leaf number, leaf area, and root number, and increased malondialdehyde (MDA) content of A. philoxeroides seedlings, which indicated that the extracts inhibited the plant growth by damaging the membrane system of leaves. And the synthetical effect of allelopathy (SE) index indicated that EE had the greatest inhibition on the growth of A. philoxeroides. Fifty compounds were identified from the three extracts of HR using GC-MS analysis, among which 5 compounds (dibutyl phthalate, stigmasta-3,5-diene, 2,6-Di-tert-butylphenol campesterol, and neophytadiene) were identified from H. scandens root extracts for the first time. And n-hexadecanoic acid exists in all three extracts. The findings of the present study provide a novel method to potentially control the invasion of A. philoxeroides. However, field monitoring under natural conditions would be necessary to confirm in practice the results obtained with the bioassays.


Assuntos
Alelopatia , Amaranthaceae/crescimento & desenvolvimento , Humulus/química , Extratos Vegetais/isolamento & purificação , Raízes de Plantas/química
18.
Ecotoxicol Environ Saf ; 215: 112123, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33721666

RESUMO

Alexandrium pacificum is a toxin-producing dinoflagellate with allelopathic effects. The elucidation of allelopathic mechanism of A. pacificum is of great significance for understanding A. pacificum blooms. To this end, using the model diatom Thalassiosira pseudonana as a target species, we observed changes in physiological, biochemical and gene transcription of T. pseudonana upon being co-cultured with A. pacificum. We found reciprocal effects between A. pacificum and T. pseudonana, and corroborated A. pacificum's allelopathy on T. pseudonana by observing inhibitory effects of filtrate from A. pacificum culture on the growth of T. pseudonana. We also found that co-culturing with A. pacificum, the expression of T. pseudonana genes related to photosynthesis, oxidative phosphorylation, antioxidant system, nutrient absorption and energy metabolism were drastically influenced. Coupled with the alterations in Fv/Fm (the variable/maximum fluorescence ratio), activity of superoxide dismutase, contents of malondialdehyde, neutral lipid and total protein in T. pseudonana co-cultured with A. pacificum, we propose that A. pacificum allelopathy could reduce the efficiency of photosynthesis and energy metabolism of T. pseudonana and caused the oxidative stress, while the nutrient absorption was also affected by allelopathic effects. The resultant data potentially uncovered the allelopathic molecular mechanism of A. pacificum to model alga T. pseudonana. The changes in nutrient uptake and even energy metabolism in T. pseudonana, as an adaptation to environmental conditions, may prevent it from stress-related injuries. Our finding might advance the understanding of allelopathic mechanism of A. pacificum.


Assuntos
Alelopatia , Diatomáceas/fisiologia , Dinoflagelados/fisiologia , Dinoflagelados/metabolismo , Laboratórios , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos
19.
PLoS One ; 16(2): e0246685, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33561161

RESUMO

According to the 'novel weapons hypothesis', invasive success depends on harmful plant biochemicals, including allelopathic antimicrobial roots exudate that directly inhibit plant growth and soil microbial activity. However, the combination of direct and soil-mediated impacts of invasive plants via allelopathy remains poorly understood. Here, we addressed the allelopathic effects of an invasive plant species (Rhus typhina) on a cultivated plant (Tagetes erecta), soil properties and microbial communities. We grew T. erecta on soil samples at increasing concentrations of R. typhina root extracts and measured both plant growth and soil physiological profile with community-level physiological profiles (CLPP) using Biolog Eco-plates incubation. We found that R. typhina root extracts inhibit both plant growth and soil microbial activity. Plant height, Root length, soil organic carbon (SOC), total nitrogen (TN) and AWCD were significantly decreased with increasing root extract concentration, and plant above-ground biomass (AGB), below-ground biomass (BGB) and total biomass (TB) were significantly decreased at 10 mg·mL-1 of root extracts. In particular, root extracts significantly reduced the carbon source utilization of carbohydrates, carboxylic acids and polymers, but enhanced phenolic acid. Redundancy analysis shows that soil pH, TN, SOC and EC were the major driving factors of soil microbial activity. Our results indicate that strong allelopathic impact of root extracts on plant growth and soil microbial activity by mimicking roots exudate, providing novel insights into the role of plant-soil microbe interactions in mediating invasion success.


Assuntos
Alelopatia/fisiologia , Desenvolvimento Vegetal/fisiologia , Solo/química , Biomassa , Carbono/metabolismo , Espécies Introduzidas/tendências , Microbiota/fisiologia , Nitrogênio/metabolismo , Raízes de Plantas/fisiologia , Plantas/metabolismo , Plantas/microbiologia , Rhus/metabolismo , Rhus/toxicidade , Microbiologia do Solo , Tagetes/crescimento & desenvolvimento , Tagetes/metabolismo
20.
Sci Total Environ ; 776: 145942, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33640554

RESUMO

Having a pivotal role in biogeochemical cycles, litter decomposition affects plant growth and regeneration by inducing the release of allelochemicals. The aim of this study was to assess the role of the microbiota in modulating the allelopathic effects of freshly fallen and decomposed leaf litter. To disentangle the chemical and microbial effects, bioassays were carried out on four target plants in sterile and non-sterile conditions. All litter types were characterized by carbon-13 cross polarization magic-angle spinning nuclear magnetic resonance (13C-CPMAS NMR) spectroscopy, and the associated fungal and bacterial microbiota were described by next-generation sequencing. When the litter extract was sterilized, freshly fallen litter severely inhibited the plant root growth, but during decomposition, the allelopathic effect rapidly decreased. Root growth was negatively correlated with extractable carbon and positively correlated with parameters associated with tissue lignification. In non-sterile conditions, the living microbiota modulated the leaf litter allelopathic effects of mitigation (26.5% of cases) and exacerbation (26.6% of cases). The mitigation effect was more frequent and intense in stressful conditions, i.e., highly phytotoxic freshly fallen litter, than in benign environments, i.e., decomposed litter. Finally, we identified specific bacterial and fungal operational taxonomic units (OTUs) that could be involved in the mediation of the litter allelopathic effect. This study highlights the importance of studying allelopathy in both sterile conditions and in the presence of a living microbiota to assess the role of litter chemistry and the potential impact of plant detritus on the agro-ecosystem and natural plant communities.


Assuntos
Ecossistema , Microbiota , Alelopatia , Bactérias , Fungos , Folhas de Planta , Plantas
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