scholarly journals Antifungal potency and modes of action of a novel olive tree defensin against closely related ascomycete fungal pathogens

2019 ◽  
Author(s):  
Hui Li ◽  
Siva L. S. Velivelli ◽  
Dilip M. Shah
Keyword(s):  
Antifungal Activity ◽  
Fungal Pathogen ◽  
Fungal Pathogens ◽  
Olive Tree ◽  
In Planta ◽  
Core Motif ◽  
Antifungal Peptides ◽  
Cultivated Species ◽  
High Concentrations

AbstractAntimicrobial peptides play a pivotal role in the innate immunity of plants. Defensins are cysteine-rich antifungal peptides with multiple mechanisms of action (MOA). A novel Oleaceae-specific defensin gene family was discovered in the genome sequences of the wild and cultivated species of a perennial olive tree, Olea europaea. Antifungal properties of an olive tree defensin OefDef1.1 were investigated against a necrotrophic ascomycete fungal pathogen Botrytis cinerea in vitro and in planta. OefDef1.1 displayed potent antifungal activity against this pathogen by rapidly permeabilizing the plasma membrane of the conidial and germling cells. Interestingly, it was translocated to the cytoplasm and induced reactive oxygen species in the germlings, but not in the conidia. In medium containing high concentrations of Na1+, antifungal activity of OefDef1.1 against B. cinerea was significantly reduced. In contrast, OefDef1.1_V1 variant in which the γ-core motif of OefDef1.1 was replaced by that of a Medicago truncatula defensin MtDef4 displayed Na1+-tolerant antifungal activity and was more potent in reducing the virulence of B. cinerea in planta. OefDef1.1 also exhibited potent antifungal activity against three hemibiotrophic ascomycete pathogens Fusarium graminearum, F. oxysporum and F. virguliforme. Significant differences were observed among the four pathogens in their responses to OefDef1.1 in growth medium with or without the high concentrations of Na1+. The varied responses of closely related ascomycete pathogens to this defensin have implications for engineering disease resistance in plants.

scholarly journals Antifungal Potency and Modes of Action of a Novel Olive Tree Defensin Against Closely Related Ascomycete Fungal Pathogens

2019 ◽  
Vol 32 (12) ◽  
pp. 1649-1664 ◽  
Author(s):  
Hui Li ◽  
Siva L. S. Velivelli ◽  
Dilip M. Shah
Keyword(s):  
Antifungal Activity ◽  
Fungal Pathogens ◽  
Olive Tree ◽  
Gray Mold ◽  
Elevated Concentration ◽  
High Concentration ◽  
Core Motif ◽  
Modes Of Action ◽  
Cultivated Species

Antimicrobial peptides play a pivotal role in the innate immunity of plants. Defensins are cysteine-rich antifungal peptides with multiple modes of action. A novel Oleaceae-specific defensin gene family has been discovered in the genome sequences of wild and cultivated species of a perennial olive tree, Olea europaea. OefDef1.1, a member of this defensin family, potently inhibits the in-vitro growth of ascomycete fungal pathogens Botrytis cinerea and three Fusarium spp. OefDef1.1 rapidly permeabilizes the plasma membrane of the conidial and germling cells of B. cinerea. Interestingly, it induces reactive oxygen species and translocates to the cytoplasm only in the germlings but not in the conidia. In medium containing a high concentration of Na1+, antifungal activity of OefDef1.1 is significantly reduced. Surprisingly, a chimeric OefDef1.1 peptide containing the γ-core motif of a Medicago truncatula defensin, MtDef4, displays Na1+-tolerant antifungal activity. In a phospholipid-protein overlay assay, the chimeric peptide exhibits stronger binding to its phosphoinositide partners than OefDef1.1 and is also more potent in inhibiting gray mold disease on the surface of Nicotiana benthamiana and lettuce leaves than OefDef1.1. Significant differences are observed among the four ascomycete pathogens in their responses to OefDef1.1 in growth medium with or without the elevated concentration of Na1+. The varied responses of closely related ascomycete pathogens to this defensin have implications for engineering disease resistance in plants.

Investigating the potential of unsaturated fatty acids as antifungal crop protective agents

2020 ◽  
pp. 1-13
Author(s):  
Azadeh Yasari ◽  
Nuanyi Liang ◽  
Aidin Foroutan ◽  
Michael G. Gänzle ◽  
Stephen E. Strelkov ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Disease Severity ◽  
Fungal Pathogens ◽  
Unsaturated Fatty Acids ◽  
Crop Protection ◽  
Leptosphaeria Maculans ◽  
Pathogenic Fungi ◽  
In Planta ◽  
High Concentrations

Pathogenic fungi cause significant yield losses and quality reductions to many crops including canola, wheat, and barley. Toxic metabolites produced by fungal pathogens, along with excessive application of synthetic fungicides, can also pose risks to human and livestock health. Hydroxy unsaturated fatty acids (HUFAs) are novel alternatives to commonly used fungicides. Here, the antifungal activities of two HUFAs, coriolic acid (CA) and ricinoleic acid (RA), were assessed in vitro and in planta for their activity against the important phytopathogens Fusarium graminearum Schwabe, Pyrenophora tritici-repentis (Died.) Drechsler, Pyrenophora teres f. teres Drechsler, Sclerotinia sclerotiorum (Lib.) de Bary, Leptosphaeria maculans Ces. & De Not., and Aspergillus niger Tiegh. on selected media, monocots or dicots. The results in vitro indicated that both CA and RA showed the strongest inhibitory activity against L. maculans and A. niger, but their activities varied with different fungi. On wheat and barley, CA but not RA reduced disease severity caused by Pyrenophora spp.; on canola, treatment with high levels of CA and RA led to oxidative damage of the plant tissues, and treatment with low concentrations of CA and RA did not reduce disease severity caused by L. maculans or S. sclerotiorum on canola. Our findings suggest that the utility of HUFAs in reducing disease severity caused by pathogenic fungi depends on the dosage and the plant and fungus targeted. High concentrations of HUFA can be phytotoxic on certain plants. In addition to their direct antifungal properties, additional mechanisms may be involved in the disease reduction of CA, suggesting the need for further evaluation of its potential use in crop protection.

scholarly journals Crinipellins A and I, Two Diterpenoids from the Basidiomycete Fungus Crinipellis rhizomaticola, as Potential Natural Fungicides

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2377 ◽  
Author(s):  
Jae Han ◽  
Mira Oh ◽  
Yu Lee ◽  
Jaehyuk Choi ◽  
Gyung Choi ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Ethyl Acetate ◽  
Culture Filtrate ◽  
Fungal Pathogens ◽  
Its Region ◽  
In Planta ◽  
Chemical Structures ◽  
Wide Range ◽  
Wheat Leaf

In the course of screening for microbes with antifungal activity, we found that the culture filtrate of the IUM00035 isolate exhibited strong antifungal activity against Magnaporthe oryzae and Colletotrichum coccodes in planta. Based on the phylogenetic analysis with the ITS region, the IUM00035 isolate was identified as Crinipellis rhizomaticola. To identify antifungal compounds from the C. rhizomaticola IUM00035 isolate, the culture filtrate of the isolate was partitioned with ethyl acetate and n-butanol and, consequently, two active compounds were isolated from the ethyl acetate extract. The chemical structures of the isolated compounds were determined as crinipellin A (1) and a new crinipellin derivative, crinipellin I (2), by NMR spectral analyses and a comparison of their NMR and MS data with those reported in the literature. Crinipellin A (1) exhibited a wide range of antifungal activity in vitro against C. coccodes, M. oryzae, Botrytis cinerea, and Phytophthora infestans (MICs = 1, 8, 31, and 31 µg/mL, respectively). Furthermore, when plants were treated with crinipellin A (1) (500 µg/mL) prior to inoculation with fungal pathogens, crinipellin A (1) exhibited disease control values of 88%, 65%, and 60% compared with non-treatment control against tomato late blight, pepper anthracnose, and wheat leaf rust, respectively. In contrast to crinipellin A (1), crinipellin I (2) showed weak or no activity (MICs > 250 µg/mL). Taken together, our results show that the C. rhizomaticola IUM00035 isolate suppresses the development of plant fungal diseases, in part through the production of crinipellin A (1).

scholarly journals Rhizosphere-enriched microbes as a pool to design synthetic communities for reproducible beneficial outputs

2019 ◽  
Author(s):  
Maria-Dimitra Tsolakidou ◽  
Ioannis A Stringlis ◽  
Natalia Fanega-Sleziak ◽  
Stella Papageorgiou ◽  
Antria Tsalakou ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Fungal Pathogens ◽  
Growth Parameters ◽  
Tomato Plants ◽  
Beneficial Effects ◽  
Negative Effect ◽  
Tomato Growth ◽  
In Vitro Antifungal Activity

Abstract Composts represent a sustainable way to suppress diseases and improve plant growth. Identification of compost-derived microbial communities enriched in the rhizosphere of plants and characterization of their traits, could facilitate the design of microbial synthetic communities (SynComs) that upon soil inoculation could yield consistent beneficial effects towards plants. Here, we characterized a collection of compost-derived bacteria, previously isolated from tomato rhizosphere, for in vitro antifungal activity against soil-borne fungal pathogens and for their potential to change growth parameters in Arabidopsis. We further assessed root-competitive traits in the dominant rhizospheric genus Bacillus. Certain isolated rhizobacteria displayed antifungal activity against the tested pathogens and affected growth of Arabidopsis, and Bacilli members possessed several enzymatic activities. Subsequently, we designed two SynComs with different composition and tested their effect on Arabidopsis and tomato growth and health. SynCom1, consisting of different bacterial genera, displayed negative effect on Arabidopsis in vitro, but promoted tomato growth in pots. SynCom2, consisting of Bacilli, didn't affect Arabidopsis growth, enhanced tomato growth and suppressed Fusarium wilt symptoms. Overall, we found selection of compost-derived microbes with beneficial properties in the rhizosphere of tomato plants, and observed that application of SynComs on poor substrates can yield reproducible plant phenotypes.

scholarly journals A Microbial Fermentation Mixture Reduces Fusarium Head Blight and Promotes Grain Weight but does not impact Septoria tritici blotch

2021 ◽  
Author(s):  
Tony Twamley ◽  
Mark Gaffney ◽  
Angela Feechan
Keyword(s):  
Fusarium Head Blight ◽  
Fungal Pathogens ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Microbial Fermentation ◽  
In Planta ◽  
Head Blight ◽  
Zymoseptoria Tritici ◽  
The Impact

AbstractFusarium graminearum and Zymoseptoria tritici cause economically important diseases of wheat. F. graminearum is one of the primary causal agents of Fusarium head blight (FHB) and Z. tritici is the causal agent of Septoria tritici blotch (STB). Alternative control methods are required in the face of fungicide resistance and EU legislation which seek to cut pesticide use by 2030. Both fungal pathogens have been described as either hemibiotrophs or necrotrophs. A microbial fermentation-based product (MFP) was previously demonstrated to control the biotrophic pathogen powdery mildew, on wheat. Here we investigated if MFP would be effective against the non-biotrophic fungal pathogens of wheat, F. graminearum and Z. tritici. We assessed the impact of MFP on fungal growth, disease control and also evaluated the individual constituent parts of MFP. Antifungal activity towards both pathogens was found in vitro but MFP only significantly decreased disease symptoms of FHB in planta. In addition, MFP was found to improve the grain number and weight, of uninfected and F. graminearum infected wheat heads.

scholarly journals Rhizosphere-enriched microbes as a pool to design synthetic communities for reproducible beneficial outputs

2018 ◽  
Author(s):  
Maria-Dimitra Tsolakidou ◽  
Ioannis A. Stringlis ◽  
Natalia Fanega-Sleziak ◽  
Stella Papageorgiou ◽  
Antria Tsalakou ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Fungal Pathogens ◽  
Growth Parameters ◽  
Tomato Plants ◽  
Beneficial Effects ◽  
Negative Effect ◽  
Tomato Growth ◽  
Selection Of

AbstractComposts represent a sustainable way to suppress diseases and improve plant growth. Identification of compost-derived microbial communities enriched in the rhizosphere of plants and characterization of their traits, could facilitate the design of microbial synthetic communities (SynComs) that upon soil inoculation could yield consistent beneficial effects towards plants. Here, we characterized a collection of compost-derived bacteria, previously isolated from tomato rhizosphere, forin vitroantifungal activity against soil-borne fungal pathogens and for their potential to change growth parameters inArabidopsis. We further assessed root-competitive traits in the dominant rhizospheric genusBacillus. Certain isolated rhizobacteria displayed antifungal activity against the tested pathogens and affected growth ofArabidopsis, and Bacilli members possessed several enzymatic activities. Subsequently, we designed two SynComs with different composition and tested their effect onArabidopsisand tomato growth and health. SynCom1, consisting of different bacterial genera, displayed negative effect onArabidopsis in vitro, but promoted tomato growth in pots. SynCom2, consisting of Bacilli, didn’t affectArabidopsisgrowth, enhanced tomato growth and suppressed Fusarium wilt symptoms. Overall, we found selection of compost-derived microbes with beneficial properties in the rhizosphere of tomato plants, and observed that application of SynComs on poor substrates can yield reproducible plant phenotypes.

scholarly journals Antifungal Activity of Silver Ions and Nanoparticles on Phytopathogenic Fungi

Plant Disease ◽  
2009 ◽  
Vol 93 (10) ◽  
pp. 1037-1043 ◽  
Author(s):  
Young-Ki Jo ◽  
Byung H. Kim ◽  
Geunhwa Jung
Keyword(s):  
Antifungal Activity ◽  
Colony Formation ◽  
Magnaporthe Grisea ◽  
Silver Ions ◽  
Pathogenic Fungi ◽  
Chloride Ions ◽  
Plant Diseases ◽  
Plant Pathogenic Fungi ◽  
In Planta

Silver in ionic or nanoparticle forms has a high antimicrobial activity and is therefore widely used for various sterilization purposes including materials of medical devices and water sanitization. There have been relatively few studies on the applicability of silver to control plant diseases. Various forms of silver ions and nanoparticles were tested in the current study to examine the antifungal activity on two plant-pathogenic fungi, Bipolaris sorokiniana and Magnaporthe grisea. In vitro petri dish assays indicated that silver ions and nanoparticles had a significant effect on the colony formation of these two pathogens. Effective concentrations of the silver compounds inhibiting colony formation by 50% (EC50) were higher for B. sorokiniana than for M. grisea. The inhibitory effect on colony formation significantly diminished after silver cations were neutralized with chloride ions. Growth chamber inoculation assays further confirmed that both ionic and nanoparticle silver significantly reduced these two fungal diseases on perennial ryegrass (Lolium perenne). Particularly, silver ions and nanoparticles effectively reduced disease severity with an application at 3 h before spore inoculation, but their efficacy significantly diminished when applied at 24 h after inoculation. The in vitro and in planta evaluations of silver indicated that both silver ions and nanoparticles influence colony formation of spores and disease progress of plant-pathogenic fungi. In planta efficacy of silver ions and nanoparticles is much greater with preventative application, which may promote the direct contact of silver with spores and germ tubes, and inhibit their viability.

scholarly journals Copper Supplementation in Watering Solution Reaches the Xylem But Does Not Protect Tobacco Plants Against Xylella fastidiosa Infection

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 724-730 ◽  
Author(s):  
Qing Ge ◽  
Paul A. Cobine ◽  
Leonardo De La Fuente
Keyword(s):  
Biofilm Formation ◽  
Inductively Coupled Plasma ◽  
Tap Water ◽  
Xylella Fastidiosa ◽  
In Vitro Study ◽  
Optical Emission ◽  
In Planta ◽  
Inductively Coupled ◽  
High Concentrations

Xylella fastidiosa is a xylem-limited plant pathogenic bacterium that causes disease in many crops worldwide. Copper (Cu) is an antimicrobial agent widely used on X. fastidiosa hosts to control other diseases. Although the effects of Cu for control of foliar pathogens are well known, it is less studied on xylem-colonizing pathogens. Previous results from our group showed that low concentrations of CuSO4 increased biofilm formation, whereas high concentrations inhibited biofilm formation and growth in vitro. In this study, we conducted in planta experiments to determine the influence of Cu in X. fastidiosa infection using tobacco as a model. X. fastidiosa-infected and noninfected plants were watered with tap water or with water supplemented with 4 mM or 8 mM of CuSO4. Symptom progression was assessed, and sap and leaf ionome analysis was performed by inductively coupled plasma with optical emission spectroscopy. Cu uptake was confirmed by increased concentrations of Cu in the sap of plants treated with CuSO4-amended water. Leaf scorch symptoms in Cu-supplemented plants showed a trend toward more severe at later time points. Quantification of total and viable X. fastidiosa in planta indicated that CuSO4-amended treatments did not inhibit but slightly increased the growth of X. fastidiosa. Cu in sap was in the range of concentrations that promote X. fastidiosa biofilm formation according to our previous in vitro study. Based on these results, we proposed that the plant Cu homeostasis machinery controls the level of Cu in the xylem, preventing it from becoming elevated to a level that would lead to bacterial inhibition.

scholarly journals Application of Plant Extracts to Control Postharvest Gray Mold and Susceptibility of Apple Fruits to B. cinerea from Different Plant Hosts

Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1430 ◽  
Author(s):  
Lina Šernaitė ◽  
Neringa Rasiukevičiūtė ◽  
Alma Valiuškaitė
Keyword(s):  
Antifungal Activity ◽  
Fungal Pathogens ◽  
Plant Protection ◽  
Gray Mold ◽  
Postharvest Disease ◽  
Cinnamon Extract ◽  
Wide Range ◽  
Plant Hosts ◽  
Apple Fruits

Sustainable plant protection can be applied on apples against fungal pathogens such as Botrytis cinerea (which is responsible for gray mold)—a significant global postharvest disease. This pathogen can affect a wide range of hosts; and fruits may have variable susceptibilities to B. cinerea from different plant hosts. New possibilities to control gray mold in food production are under demand due to the emergence of resistance against antifungal agents in fungal pathogens. Cinnamon, pimento, and laurel extracts were previously assessed for antifungal activities under in vitro conditions and were found to have the potential to be effective against postharvest gray mold. Therefore, this study aimed to investigate the antifungal activity of cinnamon, pimento, and laurel extracts in vitro and against postharvest gray mold on apples to determine the susceptibility of apple fruits to B. cinerea from different plant hosts, and to analyze the chemical composition of the extracts. Apples (cv. “Connell Red”) were treated with different concentrations of extracts and inoculated with B. cinerea isolates from apple and strawberry followed by evaluation of in vitro antifungal activity. The results reveal that most of the concentrations of the extracts that were investigated were not efficient enough when assessed in the postharvest assay, despite having demonstrated a high in vitro antifungal effect. Apples were less susceptible to B. cinerea isolated from strawberry. To conclude, cinnamon extract was found to be the most effective against apple gray mold; however, higher concentrations of the extracts are required for the efficient inhibition of B. cinerea in fruits during storage.

scholarly journals Antifungal Activity of Saponins from the Fruit Pericarp of Sapindus mukorossi against Venturia inaequalis and Botrytis cinerea

Plant Disease ◽  
2018 ◽  
Vol 102 (5) ◽  
pp. 991-1000 ◽  
Author(s):  
Franziska M. Porsche ◽  
Daniel Molitor ◽  
Marco Beyer ◽  
Sophie Charton ◽  
Christelle André ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Antifungal Activity ◽  
Botrytis Cinerea ◽  
Fungal Pathogens ◽  
High Performance ◽  
High Resolution Mass Spectrometry ◽  
Venturia Inaequalis ◽  
Field Trials ◽  
Fruit Pericarp

The antifungal activity of an aqueous extract (AE) and the solid fraction of a chloroform-methanol fruit pericarp extract (CME) of Sapindus mukorossi resolved in water was tested for the first time against Venturia inaequalis and Botrytis cinerea—two important fungal pathogens worldwide. In the greenhouse, a CME (1% vol/vol) spray significantly reduced V. inaequalis symptoms and sporulation (99%) on apple seedling leaves (P ≤ 0.05). In field trials, applications of AE (1% vol/vol) reduced the disease severity of B. cinerea on grape, on average, by 63%. Extracts were fractionated by high-performance liquid chromatography and the bioefficacy of the fractions was tested in vitro. Some components of the most fungicidal fraction were identified by liquid chromatography-high resolution mass spectrometry as saponins: sapindoside B (accounting for ≥98% of the total constituents), hederagenin-pentosylhexoside, and oleanolic acid-hexosyl-deoxyhexosyl-hexoside. This fraction inhibited the mycelial growth of V. inaequalis and B. cinerea by 45 and 43%, respectively.

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