Special Issue "Secondary Metabolites and Eco-friendly Techniques for Agricultural Weed/Pest Management"

A special issue of Plants (ISSN 2223-7747). This special issue belongs to the section "Plant Physiology and Metabolism".

Deadline for manuscript submissions: closed (20 September 2020).

Special Issue Editors

Dr. Fabrizio Araniti
Website
Guest Editor
Locality Feo di Vito, Department AGRARIA, University Mediterranea of Reggio Calabria, 89124 SNC, Reggio Calabria, Italy
Interests: allelopathy; secondary metabolites; essential oils; weed management; plant nutrition; metabolomics; mode of action; chemical interaction; bio-herbicides
Special Issues and Collections in MDPI journals
Dr. Marco Landi
Website
Co-Guest Editor
1 Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124, Pisa, Italy
2 CIRSEC, Centre for Climatic Change Impact, University of Pisa, Via del Borghetto 80, I-56124, Pisa, Italy
Interests: anthocyanin; chemical ecology; nutraceutic; plant ecophysiology; secondary metabolism; wild edible species
Special Issues and Collections in MDPI journals
Dr. Vito Armando Laudicina
Website
Co-Guest Editor
University of Palermo; Department of agricultural, food and forestry science, Viale delle Scienze, Palermo, Italy
Interests: soil fertility; sustainable agriculture; plant–soil–microbial interactions; essential oils; phytotoxicity; bioherbicides; weed management
Prof. Maria Rosa Abenavoli
Website
Co-Guest Editor
Università degli Studi di Reggio Calabria, Reggio Calabria, Italy
Interests: allelopathy; phytotoxicity; mode of action; secondary metabolites; natural herbicides; mineral nutrition

Special Issue Information

Dear Colleagues,

In agro-ecosystems, pests (insects, weeds, etc.) compete with crops for edaphic resources, negatively affecting both quality and crop yields. Presently, the use of synthetic herbicides and pesticides, which are easy to apply and accessible to farmers, is the most common and effective method for pest management. Nevertheless, the negative impact of these synthetic chemicals on the environment and human health together with the development of herbicide/pesticide-resistant pests are shifting the attention to alternative pest control technologies based on natural compounds. Natural or natural-like molecules, characterized by less toxicity, new sites, and multimechanisms of action, could represent a valid alternative strategy for pest control in the framework of a sustainable agriculture. Further, the diversity of molecular structures from living sources should provide novel chemical skeletons or templates that are unlikely to be produced by traditional pesticide synthesis programs. In recent years, many natural herbicides/pesticides have been isolated from bacteria to fungi; on the other hand, few natural compounds employable as herbicides for weed control have been obtained from higher plants. Therefore, this Special Issue deals with the use of secondary metabolites produced by plants for the isolation and identification of new candidates for the production of novel bioherbicides/-pesticides with new modes of action and low toxicity for the environment and human health. The Special Issue is mainly focused, but not restricted on:

  • Allelopathy;
  • Isolation and identification of natural compounds from plants with biological activity against pests;
  • Identification of the target and mode of action of pure natural molecules and/or mixtures on weed/pest physiology and metabolism;
  • Use of natural products against stored products insects;
  • Use of natural products as repellent/attractive agents against parasites (e.g., Cuscuta sp.; Orobanche sp.; Striga sp.) and pests (insects, nematodes, mites, etc.);
  • Use of allelopathic crops in crop rotation; 
  • Use of glucosinolates and/or others natural compounds as biofumigants for the management of soil-borne pathogens;
  • Synthesis of ecofriendly natural-like compounds with biological activity against weeds/pests;
  • Use of eco-friendly techniques in weed/pest management.

Prof. Maria Rosa Abenavoli
Dr. Fabrizio Araniti
Dr. Marco Landi
Dr. Vito Armando Laudicina
Guest Editors

Manuscript Submission Information

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Keywords

  • Sustainable agriculture
  • Secondary metabolites
  • Natural compounds as elicitors
  • Allelopathy
  • Essential oils in crop protection
  • Allelopathic crops
  • Botanical herbicide
  • Phytotoxins
  • Natural herbicide
  • Natural fungicide
  • Natural insecticide
  • Natural nematocide
  • Biological control
  • Omics
  • Mode of action

Published Papers (12 papers)

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Research

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Open AccessArticle
Profiling Volatile Terpenoids from Calabrian Pine Stands Infested by the Pine Processionary Moth
Plants 2020, 9(10), 1362; https://doi.org/10.3390/plants9101362 - 14 Oct 2020
Abstract
Terpenoids make up the biggest and most diversified class of chemical substances discovered in plants, encompassing over 40,000 individual compounds. In conifers, the production of terpenoids, either as oleoresin or emitted as volatile compounds, play an important role in the physical and chemical [...] Read more.
Terpenoids make up the biggest and most diversified class of chemical substances discovered in plants, encompassing over 40,000 individual compounds. In conifers, the production of terpenoids, either as oleoresin or emitted as volatile compounds, play an important role in the physical and chemical defence responses against pathogens and herbivores. In the present work, we examined, for the first time to the best of our knowledge, the terpenic defensive relations of Calabrian pine (Pinus nigra subsp. laricio (Poiret) Maire), facing the attack of the pine processionary moth (Thaumetopoea pityocampa (Denis and Schiffermüller, 1775)), brought about in the open on adult plant individuals growing at two distinct forest sites. Among the volatile terpenoids emitted from pine needles, bornyl acetate [(4,7,7-trimethyl-3-bicyclo[2.2.1]heptanyl) acetate] was the most frequently and selectively associated with the infestation, increasing during the period of most intense trophic activity of the caterpillars (defoliation), and decreasing thereafter. Although further work is needed to clarify whether the observed response reflects defence reactions and/or they are involved in communication among the infested plants and their biotic environment, the present results boost the currently growing interest in the isolation and characterization of plant secondary metabolites that can be used to control pests, pathogens, and weeds. Full article
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Open AccessArticle
Phytotoxicity, Morphological, and Metabolic Effects of the Sesquiterpenoid Nerolidol on Arabidopsis thaliana Seedling Roots
Plants 2020, 9(10), 1347; https://doi.org/10.3390/plants9101347 - 12 Oct 2020
Abstract
Natural herbicides that are based on allelopathy of compounds, can offer effective alternatives to chemical herbicides towards sustainable agricultural practices. Nerolidol, a sesquiterpenoid alcohol synthesized by many plant families, was shown to be the most effective allelopathic compound in a preliminary screening performed [...] Read more.
Natural herbicides that are based on allelopathy of compounds, can offer effective alternatives to chemical herbicides towards sustainable agricultural practices. Nerolidol, a sesquiterpenoid alcohol synthesized by many plant families, was shown to be the most effective allelopathic compound in a preliminary screening performed with several other sesquiterpenoids. In the present study, Arabidopsis thaliana seedlings were treated for 14 d with various cis-nerolidol concentrations (0, 50, 100, 200, 400, and 800 µM) to investigate its effects on root growth and morphology. To probe the underlying changes in root metabolome, we conducted untargeted gas chromatography mass spectrometry (GC-MS) based metabolomics to find out the specificity or multi-target action of this sesquiterpenoid alcohol. Oxidative stress (measured as levels of H2O2 and malondialdehyde (MDA) by-product) and antioxidant enzyme activities, i.e., superoxide dismutase (SOD) and catalase (CAT) were also evaluated in the roots. Nerolidol showed an IC50 (120 µM), which can be considered low for natural products. Nerolidol caused alterations in root morphology, brought changes in auxin balance, induced changes in sugar, amino acid, and carboxylic acid profiles, and increased the levels of H2O2 and MDA in root tissues in a dose-dependent manner. Several metabolomic-scale changes induced by nerolidol support the multi-target action of nerolidol, which is a positive feature for a botanical herbicide. Though it warrants further mechanistic investigation, nerolidol is a promising compound for developing a new natural herbicide. Full article
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Open AccessArticle
Phytotoxic Activity of the Natural Compound Norharmane on Crops, Weeds and Model Plants
Plants 2020, 9(10), 1328; https://doi.org/10.3390/plants9101328 - 09 Oct 2020
Abstract
Norharmane is a secondary metabolite that appears in different species of land plants. In this paper, we investigated for the first time the specificity of norharmane through germination and growth tests on some crops as Zea mays L. (maize), Triticum aestivum L. (wheat), [...] Read more.
Norharmane is a secondary metabolite that appears in different species of land plants. In this paper, we investigated for the first time the specificity of norharmane through germination and growth tests on some crops as Zea mays L. (maize), Triticum aestivum L. (wheat), Oryza sativa L. (rice) and Lactuca sativa L. (lettuce) and weeds as Amaranthus retroflexus L. (amaranth), Echinochloa crus-galli L. (barnyard grass), Plantago lanceolata L. (ribwort), Portulaca oleracea L. (common purslane) and Avena fatua L. (wild oat), and its phytotoxic capacity on the metabolism of adult Arabidopsis thaliana L. (thale cress) by measuring chlorophyll a fluorescence, pigment content, total proteins, osmotic potential and morphological analysis. Norharmane had an inhibitory effect on the germination of A. fatua and P. lanceolata, and the growth of P. oleracea, E. crus-galli and A. retroflexus. On adult A. thaliana plants, the compound was more effective to watering, leading to water stress that compromised the growth of the plants and ultimately affected the photosynthetic apparatus. Therefore, this research shows that norharmane not only affects seedlings’ metabolism, but also damages the metabolism of adult plants and can be a potential model for a future bioherbicide given its specificity. Full article
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Open AccessArticle
Potential Effects of Essential Oils Extracted from Mediterranean Aromatic Plants on Target Weeds and Soil Microorganisms
Plants 2020, 9(10), 1289; https://doi.org/10.3390/plants9101289 - 29 Sep 2020
Abstract
Essential oils (EOs), extracted from aromatic plants, have been proposed as candidates to develop natural herbicides. This study aimed to evaluate the herbicidal potential of Thymbra capitata (L.) Cav., Mentha × piperita L. and Santolina chamaecyparissus L. essential oils (EOs) on Avena fatua [...] Read more.
Essential oils (EOs), extracted from aromatic plants, have been proposed as candidates to develop natural herbicides. This study aimed to evaluate the herbicidal potential of Thymbra capitata (L.) Cav., Mentha × piperita L. and Santolina chamaecyparissus L. essential oils (EOs) on Avena fatua L., Echinochloa crus-galli (L.) P. Beauv, Portulaca oleracea L. and Amaranthus retroflexus L. and their effects on soil microorganisms. A pot experiment was set up and three EOs at three doses were applied by irrigation. Efficacy and effects of EOs on weed growth were determined. Soil microbial biomass carbon and nitrogen, microbial respiration, and the main microbial groups were determined at days 7, 28 and 56. EOs demonstrated herbicidal activity, increasing their toxicity with the dose. T. capitata was the most effective against all weeds at the maximum dose. P. oleracea was the most resistant weed. Soil microorganisms, after a transient upheaval period induced by the addition of EOs, recovered their initial function and biomass. T. capitata EO at the highest dose did not allow soil microorganisms to recover their initial functionality. EOs exhibited great potential as natural herbicides but the optimum dose of application must be identified to control weeds and not negatively affect soil microorganisms. Full article
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Open AccessArticle
Chemical Composition of a Supercritical Fluid (Sfe-CO2) Extract from Baeckea frutescens L. Leaves and Its Bioactivity Against Two Pathogenic Fungi Isolated from the Tea Plant (Camellia sinensis (L.) O. Kuntze)
Plants 2020, 9(9), 1119; https://doi.org/10.3390/plants9091119 - 29 Aug 2020
Abstract
Colletotrichum gloeosporioides and Pseudopestalotiopsis camelliae-sinensis are the two most important tea plant (Camellia sinensis L.) pathogenic fungi. Interest in natural plant extracts as alternatives to synthetic chemical fungicides to control plant pathogens is growing. In this study, the volatile fraction of Baeckea [...] Read more.
Colletotrichum gloeosporioides and Pseudopestalotiopsis camelliae-sinensis are the two most important tea plant (Camellia sinensis L.) pathogenic fungi. Interest in natural plant extracts as alternatives to synthetic chemical fungicides to control plant pathogens is growing. In this study, the volatile fraction of Baeckea frutescens L. was extracted by supercritical fluid extraction (SFE-CO2), and its chemical composition was analyzed, and investigated for its antifungal activity against C. gloeosporioides and P. camelliae. The major constituents of the volatile fraction were β-caryophyllene (28.05%), α-caryophyllene (24.02%), δ-cadinene (6.29%) and eucalyptol (5.46%) in B. frutescens SFE-CO2 extracts. The terpineol, linalool, terpinen-4-ol and eucalyptol showed strong contact antifungal activity against P. camelliae and C. gloeosporioides with median inhibitory concentration (MIC50) in the range of 0.69 μL/mL to 2.79 μL/mL and 0.62 μL/mL to 2.18 μL/mL, respectively. Additionally, the volatile fraction had high fumigation antifungal activity against P. camelliae and C. gloeosporioides with an inhibition rate between 20.87% and 92.91%. Terpineol presented the highest antifungal activity in the contact and fumigation toxicity assays. Terpineol, linalool, terpinen-4-ol and eucalyptol were associated with the most active chemical compounds in the volatile fraction against the fungi. The results suggest that B. frutescens SFE-CO2 extracts are potential ingredients to develop a natural fungicide for control of tea plant pathogens. Full article
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Open AccessArticle
Essential Oil Enriched with Oxygenated Constituents from Invasive Plant Argemone ochroleuca Exhibited Potent Phytotoxic Effects
Plants 2020, 9(8), 998; https://doi.org/10.3390/plants9080998 - 05 Aug 2020
Cited by 4
Abstract
Invasive species are considered as one of the major threats to ecosystems worldwide. Although invasive plants are regarded as a foe, they could be considered as natural resources for valuable bioactive compounds. The present study aimed to characterize the chemical composition of the [...] Read more.
Invasive species are considered as one of the major threats to ecosystems worldwide. Although invasive plants are regarded as a foe, they could be considered as natural resources for valuable bioactive compounds. The present study aimed to characterize the chemical composition of the essential oil (EO) from the invasive plant Argemone ochroleuca Sweet, collected from Saudi Arabia, as well as to evaluate its phytotoxic activity. Seventy-four compounds were characterized via GC-MS analysis of EO representing 98.75% of the overall mass. The oxygenated constituents (79.01%) were found as the main constituents, including mono- (43.27%), sesqui- (17.67%), and di-terpenes (0.53%), as well as hydrocarbons (16.81%) and carotenoids (0.73%). Additionally, 19.69% from the overall mass was characterized as non-oxygenated compounds with mono- (1.77%), sesquiterpenes (17.41%), and hydrocarbons (0.56%) as minors. From all identified constituents, trans-chrysanthenyl acetate (25.71%), γ-cadinene (11.70%), oleic acid, methyl ester (7.37%), terpinene-4-ol (4.77%), dihydromyrcenol (2.90%), α-muurolene (1.77%), and γ-himachalene (1.56%) were found as abundant. The EO of A. ochroleuca showed significant phytotoxic activity against the test plant Lactuca sativa and the noxious weed Peganum harmala. The EO attained IC50 values of 92.1, 128.6, and 131.6 µL L−1 for seedling root growth, germination, and shoot growth of L. sativa, respectively, while it had IC50 values of 134.8, 145.7, and 147.9 µL L−1, respectively, for P. harmala. Therefore, this EO could be used as a bioherbicide against weeds, while further study is recommended for the characterization of the authentic materials of the main compounds in the EO as well as for the evaluation of potency of this oil on a field scale and the determination of its biosafety. Full article
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Open AccessArticle
Evaluation of Allelopathic Activity of Chinese Medicinal Plants and Identification of Shikimic Acid as an Allelochemical from Illicium verum Hook. f.
Plants 2020, 9(6), 684; https://doi.org/10.3390/plants9060684 - 28 May 2020
Abstract
This study focused on the potential allelopathy of 50 species of Chinese medicinal plants, which are mainly distributed in the Xinjiang Uyghur Autonomous Region, Inner Mongolia, and Yunnan Province. The “sandwich method” was adopted and used for the screening for allelopathic potential among [...] Read more.
This study focused on the potential allelopathy of 50 species of Chinese medicinal plants, which are mainly distributed in the Xinjiang Uyghur Autonomous Region, Inner Mongolia, and Yunnan Province. The “sandwich method” was adopted and used for the screening for allelopathic potential among these plant species. Further phytotoxic evaluation of the candidate species was conducted by applying plant extracts to crops and weed species. The results of this study indicated that among the 50 medicinal plant species evaluated, the fruits of Illicium verum Hook. f. (star anise) showed the most significant allelopathic potential through the leaf leachates. Shikimic acid was identified to be the main bioactive compound (about 7% dry weight) in star anise by reversed-phase High Performance Liquid Chromatography (RP-HPLC) analysis. The phytotoxic bioassay indicated that both the crude extract of the Chinese star anise and the synthetic shikimic acid showed strong inhibitory activity on the radicle and hypocotyl growth of lettuce. The radicle growth inhibition of lettuce caused by the crude extract of star anise could be explained by the contribution of the biological activity of shikimic acid. In conclusion, shikimic acid could be a putative allelochemical in the fruits of Illicium verum and could be utilized in sustainable weed management. Full article
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Open AccessArticle
Weed Classification for Site-Specific Weed Management Using an Automated Stereo Computer-Vision Machine-Learning System in Rice Fields
Plants 2020, 9(5), 559; https://doi.org/10.3390/plants9050559 - 27 Apr 2020
Abstract
Site-specific weed management and selective application of herbicides as eco-friendly techniques are still challenging tasks to perform, especially for densely cultivated crops, such as rice. This study is aimed at developing a stereo vision system for distinguishing between rice plants and weeds and [...] Read more.
Site-specific weed management and selective application of herbicides as eco-friendly techniques are still challenging tasks to perform, especially for densely cultivated crops, such as rice. This study is aimed at developing a stereo vision system for distinguishing between rice plants and weeds and further discriminating two types of weeds in a rice field by using artificial neural networks (ANNs) and two metaheuristic algorithms. For this purpose, stereo videos were recorded across the rice field and different channels were extracted and decomposed into the constituent frames. Next, upon pre-processing and segmentation of the frames, green plants were extracted out of the background. For accurate discrimination of the rice and weeds, a total of 302 color, shape, and texture features were identified. Two metaheuristic algorithms, namely particle swarm optimization (PSO) and the bee algorithm (BA), were used to optimize the neural network for selecting the most effective features and classifying different types of weeds, respectively. Comparing the proposed classification method with the K-nearest neighbors (KNN) classifier, it was found that the proposed ANN-BA classifier reached accuracies of 88.74% and 87.96% for right and left channels, respectively, over the test set. Taking into account either the arithmetic or the geometric means as the basis, the accuracies were increased up to 92.02% and 90.7%, respectively, over the test set. On the other hand, the KNN suffered from more cases of misclassification, as compared to the proposed ANN-BA classifier, generating an overall accuracy of 76.62% and 85.59% for the classification of the right and left channel data, respectively, and 85.84% and 84.07% for the arithmetic and geometric mean values, respectively. Full article
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Open AccessCommunication
Soil or Vermiculite-Applied Microencapsulated Peppermint Oil Effects on White Mustard Initial Growth and Performance
Plants 2020, 9(4), 448; https://doi.org/10.3390/plants9040448 - 03 Apr 2020
Cited by 1
Abstract
Microencapsulated peppermint (Mentha x piperita L.) essential oil (MPEO) is a prospective botanical herbicide. A hypothesis was formulated, that the type of growth medium (vermiculite or silty clay loam soil substrate) affects the phytotoxic potential of MPEO. A pot experiment in a [...] Read more.
Microencapsulated peppermint (Mentha x piperita L.) essential oil (MPEO) is a prospective botanical herbicide. A hypothesis was formulated, that the type of growth medium (vermiculite or silty clay loam soil substrate) affects the phytotoxic potential of MPEO. A pot experiment in a randomized design assessed the effect of five doses of MPEO in a range of 0–108 g m−2 or 0–145 g m−2, mixed with vermiculite or with soil, respectively, on early growth of white mustard (Sinapis alba L. cv. Zlata), tested here as a model “weed” species. The morphologic analyses were supported by selected biochemical measurements. The two highest doses of microcapsules (from 73 to 145 g m−2) caused a significant decrease of plants’ height and biomass. An increase of anthocyanin content in the aboveground parts of mustard is supportive for the induction of defense mechanisms against MPEO-triggered stress in mustard leaves. In conclusion, MPEO appears as a promising bio-herbicide. However, we are aware that further studies on the mechanisms of action of MPEO in different weed species are necessary to test (i) whether or not the effect is consistent to be proficiently exploited for weed control in field and (ii) to deepen the biochemical and physiological reactions by the plants against MPEO treatments. Full article
Open AccessArticle
Physiological Responses to the Foliar Application of Synthetic Resistance Elicitors in Cape Gooseberry Seedlings Infected with Fusarium oxysporum f. sp. physali
Plants 2020, 9(2), 176; https://doi.org/10.3390/plants9020176 - 01 Feb 2020
Abstract
Vascular wilt caused by Fusarium oxysporum is the most limiting disease that affects cape gooseberry (Physalis peruviana L.) crops in Colombia. The use of synthetic elicitors for vascular wilt management is still scarce in Andean fruit species. The objective of the present [...] Read more.
Vascular wilt caused by Fusarium oxysporum is the most limiting disease that affects cape gooseberry (Physalis peruviana L.) crops in Colombia. The use of synthetic elicitors for vascular wilt management is still scarce in Andean fruit species. The objective of the present study was to evaluate the effect and number of foliar applications of synthetic elicitors such as jasmonic acid (JA), salicylic acid (SA), brassinosteroids (BR), or a commercial resistance elicitor based on botanical extracts (BE) on disease progress and their effect on the physiology of cape gooseberry plants inoculated with F. oxysporum f. sp. physali. Groups of ten plants were separately sprayed once, twice, or three times with a foliar synthetic elicitor, respectively. Elicitor applications were performed at the following concentrations: JA (10 mL L−1), SA (100 mg L−1), BR (1 mL L−1) and BE (2.5 mL of commercial product (Loker®) L−1). The results showed that three foliar BR, SA, or BE applications reduced the area under the disease progress, severity index, and vascular browning in comparison to inoculated plants without any elicitor spray. Three BR, SA, or BE sprays also favored stomatal conductance, water potential, growth (total dry weight and leaf area) and fluorescence parameters of chlorophyll compared with inoculated and untreated plants with no elicitor sprays. Three foliar sprays of SA, BR, or BE enhanced photosynthetic pigments (leaf total chlorophyll and carotenoid content) and proline synthesis and decreased oxidative stress in Foph-inoculated plants. In addition, the effectiveness of three foliar BR, SA, or BE sprays was corroborated by three-dimensional plot and biplot analysis, in which it can evidence that stomatal conductance, proline synthesis, and efficacy percentage were accurate parameters to predict Foph management. On the hand, JA showed the lowest level of amelioration of the negative effects of Foph inoculation. In conclusion, the use of the synthetic elicitors BR, SA, or BE can be considered as a tool complementary for the commercial management of vascular wilt in areas where this disease is a limiting factor. Full article
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Open AccessArticle
Exploiting the Allelopathic Potential of Aqueous Leaf Extracts of Artemisia absinthium and Psidium guajava against Parthenium hysterophorus, a Widespread Weed in India
Plants 2019, 8(12), 552; https://doi.org/10.3390/plants8120552 - 28 Nov 2019
Abstract
Artemisia absinthium and Psidium guajava are powerful sources of secondary metabolites, some of them with potential allelopathic activity. Both the species grow together in India with a weed (Parthenium hysterophorus) that is becoming extremely invasive. The aim of the present research [...] Read more.
Artemisia absinthium and Psidium guajava are powerful sources of secondary metabolites, some of them with potential allelopathic activity. Both the species grow together in India with a weed (Parthenium hysterophorus) that is becoming extremely invasive. The aim of the present research was to test the allelopathic effect of A. absinthium and P. guajava aqueous leaf extracts on seed germination, seedling growth (shoot and root length), as well as some biochemical parameters (enzymatic and non-enzymatic antioxidants, photosynthetic pigments, osmolytes, and malondialdehyde by-products) of P. hysterophorus plants. Leaf extracts of both A. absinthium and P. guajava constrained the germination and seedling development (root and shoot length), affected pigment content (chlorophylls, carotenoids), stimulated the activity of antioxidant enzymes, and increased the level of malondialdehyde by-products of P. hysterophorus plants. Non-enzymatic antioxidants (glutathione and ascorbic acid) in P. hysterophorus leaves were, conversely, negatively affected by both leaf extracts tested in the present experiment. Although A. absinthium was more effective than P. guajava in impacting some biochemical parameters of P. hysterophorus leaves (including a higher EC50 for seed germination), P. guajava extract showed a higher EC50 in terms of root inhibition of P. hysterophorus seedlings. The present study provides the evidence that A. absinthium and P. guajava extract could be proficiently exploited as a botanical herbicide against P. hysterophorus. Full article
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Review

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Open AccessReview
Trichoderma: The “Secrets” of a Multitalented Biocontrol Agent
Plants 2020, 9(6), 762; https://doi.org/10.3390/plants9060762 - 18 Jun 2020
Cited by 3
Abstract
The plant-Trichoderma-pathogen triangle is a complicated web of numerous processes. Trichoderma spp. are avirulent opportunistic plant symbionts. In addition to being successful plant symbiotic organisms, Trichoderma spp. also behave as a low cost, effective and ecofriendly biocontrol agent. They can set [...] Read more.
The plant-Trichoderma-pathogen triangle is a complicated web of numerous processes. Trichoderma spp. are avirulent opportunistic plant symbionts. In addition to being successful plant symbiotic organisms, Trichoderma spp. also behave as a low cost, effective and ecofriendly biocontrol agent. They can set themselves up in various patho-systems, have minimal impact on the soil equilibrium and do not impair useful organisms that contribute to the control of pathogens. This symbiotic association in plants leads to the acquisition of plant resistance to pathogens, improves developmental processes and yields and promotes absorption of nutrient and fertilizer use efficiency. Among other biocontrol mechanisms, antibiosis, competition and mycoparasitism are among the main features through which microorganisms, including Thrichoderma, react to the presence of other competitive pathogenic organisms, thereby preventing or obstructing their development. Stimulation of every process involves the biosynthesis of targeted metabolites like plant growth regulators, enzymes, siderophores, antibiotics, etc. This review summarizes the biological control activity exerted by Trichoderma spp. and sheds light on the recent progress in pinpointing the ecological significance of Trichoderma at the biochemical and molecular level in the rhizosphere as well as the benefits of symbiosis to the plant host in terms of physiological and biochemical mechanisms. From an applicative point of view, the evidence provided herein strongly supports the possibility to use Trichoderma as a safe, ecofriendly and effective biocontrol agent for different crop species. Full article
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