scholarly journals Fungal Resistance to Plant Antibiotics as a Mechanism of Pathogenesis

1999 ◽  
Vol 63 (3) ◽  
pp. 708-724 ◽  
Author(s):  
John P. Morrissey ◽  
Anne E. Osbourn
Keyword(s):  
Secondary Metabolites ◽  
Fungal Pathogens ◽  
Phytopathogenic Fungi ◽  
Rapid Expansion ◽  
Fungal Resistance ◽  
Low Molecular Weight ◽  
Plant Interactions ◽  
Mechanisms Of Resistance ◽  
Degradative Enzymes

SUMMARY Many plants produce low-molecular-weight compounds which inhibit the growth of phytopathogenic fungi in vitro. These compounds may be preformed inhibitors that are present constitutively in healthy plants (also known as phytoanticipins), or they may be synthesized in response to pathogen attack (phytoalexins). Successful pathogens must be able to circumvent or overcome these antifungal defenses, and this review focuses on the significance of fungal resistance to plant antibiotics as a mechanism of pathogenesis. There is increasing evidence that resistance of fungal pathogens to plant antibiotics can be important for pathogenicity, at least for some fungus-plant interactions. This evidence has emerged largely from studies of fungal degradative enzymes and also from experiments in which plants with altered levels of antifungal secondary metabolites were generated. Whereas the emphasis to date has been on degradative mechanisms of resistance of phytopathogenic fungi to antifungal secondary metabolites, in the future we are likely to see a rapid expansion in our knowledge of alternative mechanisms of resistance. These may include membrane efflux systems of the kind associated with multidrug resistance and innate resistance due to insensitivity of the target site. The manipulation of plant biosynthetic pathways to give altered antibiotic profiles will also be valuable in telling us more about the significance of antifungal secondary metabolites for plant defense and clearly has great potential for enhancing disease resistance for commercial purposes.

scholarly journals Natural compounds: A sustainable alternative for controlling phytopathogens

2018 ◽  
Author(s):  
María Fernanda Jiménez-Reyes ◽  
Héctor Carrasco ◽  
Andrés Olea ◽  
Evelyn Silva-Moreno
Keyword(s):  
Natural Products ◽  
Secondary Metabolites ◽  
Antifungal Agents ◽  
Phytopathogenic Fungi ◽  
Direct Application ◽  
Economic Losses ◽  
Infectious Agents ◽  
Active Compounds

Fungi are the primary infectious agents in plants causing significant economic losses in agroindustry. Traditionally, these pathogens have been treated with different synthetic fungicides such as hydroxianilides, anilinopyrimidines, and azoles, to name a few. However, the indiscriminate use of these chemicals has increased fungi resistance in plants. Natural products have been researched as a control, and an alternative to these synthetic fungicides since they are not harmful to health and contribute to the environment caring. This review describes plants extracts, essential oils, and active compounds or secondary metabolites as antifungal agents both, in vitro and in vivo. Active compounds have been recently described as the best candidates for the control of phytopathogenic fungi. When metabolized by plants, these compounds concentrations rely on the environmental conditions and pathogens incidence. However, one issue regarding the direct application of these preformed compounds in plants touch upon their low persistence in the environment, and their even lower bioavailability than synthetic fungicides. Hence the challenge is to develop useful formulations based on natural products to increase the compounds solubility facilitating thus their application in the field while maintaining their properties.

scholarly journals Heterologous Expression of Septoria lycopersici Tomatinase in Cladosporium fulvum: Effects on Compatible and Incompatible Interactions with Tomato Seedlings

1998 ◽  
Vol 11 (3) ◽  
pp. 228-236 ◽  
Author(s):  
Rachel E. Melton ◽  
Lynda M. Flegg ◽  
James K. M. Brown ◽  
Richard P. Oliver ◽  
Michael J. Daniels ◽  
...  
Keyword(s):  
Heterologous Expression ◽  
Fungal Pathogens ◽  
Phytopathogenic Fungi ◽  
Cladosporium Fulvum ◽  
Tomato Plants ◽  
Septoria Lycopersici ◽  
Tomato Pathogen ◽  
Anti Fungal ◽  
Incompatible Interactions

The anti-fungal, steroidal, glycoalkaloid saponin, α-tomatine, is present in uninfected tomato plants in substantial concentrations, and may contribute to the protection of tomato plants against attack by phytopathogenic fungi. In general, successful fungal pathogens of tomato are more resistant to α-tomatine in vitro than fungi that do not infect this plant. For a number of tomato pathogens, this resistance has been associated with the ability to detoxify α-tomatine through the action of enzymes known as tomatinases. In contrast, the biotrophic tomato pathogen Cladosporium fulvum is sensitive to α-tomatine and is unable to detoxify this saponin. This paper describes the effects of heterologous expression of the cDNA encoding tomatinase from the necrotroph Septoria lycopersici in two different physiological races of C. fulvum. Tomatinase-producing C. fulvum transformants showed increased sporulation on cotyledons of susceptible tomato lines. They also caused more extensive infection of seedlings of resistant tomato lines. Thus, α-tomatine may contribute to the ability of tomato to restrict the growth of C. fulvum in both compatible and incompatible interactions.

scholarly journals Bioactive Secondary Metabolites from Trichoderma spp. against Phytopathogenic Fungi

2020 ◽  
Vol 8 (6) ◽  
pp. 817 ◽  
Author(s):  
Raja Asad Ali Khan ◽  
Saba Najeeb ◽  
Shaukat Hussain ◽  
Bingyan Xie ◽  
Yan Li
Keyword(s):  
Secondary Metabolites ◽  
Management Strategies ◽  
Pathogenic Fungi ◽  
Phytopathogenic Fungi ◽  
Biocontrol Agents ◽  
Fungal Resistance ◽  
Comprehensive Overview ◽  
Trichoderma Spp ◽  
Trichoderma Species ◽  
Global Food Security

Phytopathogenic fungi, causing significant economic and production losses, are becoming a serious threat to global food security. Due to an increase in fungal resistance and the hazardous effects of chemical fungicides to human and environmental health, scientists are now engaged to explore alternate non-chemical and ecofriendly management strategies. The use of biocontrol agents and their secondary metabolites (SMs) is one of the potential approaches used today. Trichoderma spp. are well known biocontrol agents used globally. Many Trichoderma species are the most prominent producers of SMs with antimicrobial activity against phytopathogenic fungi. Detailed information about these secondary metabolites, when grouped together, enhances the understanding of their efficient utilization and further exploration of new bioactive compounds for the management of plant pathogenic fungi. The current literature provides the information about SMs of Trichoderma spp. in a different context. In this review, we summarize and group different antifungal SMs of Trichoderma spp. against phytopathogenic fungi along with a comprehensive overview of some aspects related to their chemistry and biosynthesis. Moreover, a brief overview of the biosynthesis pathway, action mechanism, and different approaches for the analysis of SMs and the factors affecting the regulation of SMs in Trichoderma is also discussed.

scholarly journals Regional Evaluation of Fungal Pathogen Incidence in Colombian Cocoa Crops

Agriculture ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 44
Author(s):  
Raquel Villamizar-Gallardo ◽  
Johann Osma ◽  
Oscar Ortíz-Rodriguez
Keyword(s):  
Fungal Pathogens ◽  
Morphological Variability ◽  
Phytopathogenic Fungi ◽  
Phytophthora Palmivora ◽  
In Vitro Assays ◽  
Post Conflict ◽  
Solid Media ◽  
Black Pod

The production of cocoa (Theobroma cacao L.) in Colombia has a significant environmental and socioeconomic importance as a promissory crop in the post-conflict process. The department of Norte de Santander has cocoa crops that are dramatically affected by fungal pathogens causing important losses during harvest and post-harvest. Therefore, the current study focused on the determination of the incidence of diseases caused by phytopathogenic fungi in cocoa crops, and the identification of primary phytopathogenic fungi found in biological material from different farms of the region. The study was conducted in four municipalities of the department, by sampling fruits infected with frosty pod rot (FPR) and black pod rot (BPR) that presented in situ incidence ranging from 0.37 to 21.58% and from 1.75 to 35.59%, respectively. The studied hybrid materials, together with clone TSH 65, were found to be the most susceptible, while the remaining clones were more tolerant, especially CCN 51, IMC 67, and ICS95. Fifteen strains were isolated using in vitro assays and then morphologically characterized both in solid media and by microscopy. Nine of them corresponded to the pathogen Moniliophthora roreri, and other six to Phytophthora palmivora. The isolated agents showed in vitro morphological variability, as well as the ability to adapt to different environments when growing in situ.

scholarly journals Octyl Gallate as an Intervention Catalyst to Augment Antifungal Efficacy of Caspofungin

J ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Jong Kim ◽  
Kathleen Chan ◽  
Luisa Cheng
Keyword(s):  
Cell Wall ◽  
Filamentous Fungi ◽  
Fungal Pathogens ◽  
Intervention Strategy ◽  
Cell Wall Integrity ◽  
Fungal Resistance ◽  
Alternative Intervention ◽  
Invasive Infections ◽  
Application Of Cas

Filamentous fungi such as Aspergillus spp. are opportunistic pathogens, which cause highly invasive infections, especially in immunocompromised individuals. Control of such fungal pathogens is increasingly problematic due to the small number of effective drugs available for treatment. Moreover, the increased incidence of fungal resistance to antifungal agents makes this problem a global human health issue. The cell wall integrity system of fungi is the target of antimycotic drugs echinocandins, such as caspofungin (CAS). However, echinocandins cannot completely inhibit the growth of filamentous fungal pathogens, which results in survival/escape of fungi during treatment. Chemosensitization was developed as an alternative intervention strategy, where co-application of CAS with the intervention catalyst octyl gallate (OG; chemosensitizer) greatly enhanced CAS efficacy, thus achieved ≥99.9% elimination of filamentous fungi in vitro. Based on hypersensitive responses of Aspergillus antioxidant mutants to OG, it is hypothesized that, besides destabilizing cell wall integrity, the redox-active characteristic of OG may further debilitate the fungal antioxidant system.

scholarly journals In Vitro Antibacterial, Antifungal, Nematocidal and Growth Promoting Activities of Trichoderma hamatum FB10 and Its Secondary Metabolites

2021 ◽  
Vol 7 (5) ◽  
pp. 331
Author(s):  
Alaa Baazeem ◽  
Abdulaziz Almanea ◽  
Palanisamy Manikandan ◽  
Mohammed Alorabi ◽  
Ponnuswamy Vijayaraghavan ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Secondary Metabolite ◽  
Fungal Pathogens ◽  
Xanthomonas Campestris ◽  
Green Gram ◽  
Control Group ◽  
Cell Free Extract ◽  
Trichoderma Hamatum ◽  
Growth Promoting

Microbial natural biocides have attracted much more attention in recent years in order to avoid the unrestricted use of chemical biocides in the environment. The aim of this study is to analyze the antibacterial and antifungal activities of secondary metabolites and growth promoting, nematicidal, and soil enzyme activity mediated by Trichoderma hamatum FB10. The bactericidal and fungicidal activities were performed using cell-free extract. Results revealed that the selected strain exert antibacterial activity against Acidovorax avenae, Erutimacarafavora, and Xanthomonas campestris. The selected fungal strain FB10 showed antagonistic activity against fungal pathogens such as, S. sclerotiorum, Rhizoctonia solani, Alternaria radicina, Alternaria citri, and Alternaria dauci. Among the bacterial pathogens, A. avenae showed least MIC (30 ± 2.5 µg/mL) and MBC (70 ± 1.25 µg/mL) values. T. hamatum FB10 strain synthesized bioactive volatile secondary metabolite, which effectively inhibited the growth of bacteria and fungi and indicated the presence of 6-pentyl-alpha-pyrone as the major compound (67.05%). The secondary metabolite synthesized by T. hamatum FB10 showed nematicidal activity against M. incognita eggs. Egg hatch inhibition was 78 ± 2.6% and juvenile stage mortality rate was 89 ± 2.5% when the strain FB10 was treated with nematode. The cell free extract of T. hamatum FB10 showed protease, amylase, cellulase, chitinase, glucanase activities. T. hamatum FB10 inoculated with green gram increased 11% plant height, compared to the control. The fresh weight of the experimental group inoculated with T. hamatum FB10 increased 33.6% more compared to the control group. The green gram seedlings inoculated with T. hamatum FB10 increased 18% more dry weight than control group. Soil enzymes such as, urease, phosphatase, catalase and saccharase were improved in the soil inoculated with T. hamatum FB10. These biochemical components play potent role in soil fertility, energy conversion, and in soil organic matter conversion.

scholarly journals Antagonistic effect of volatile and non-volatile compounds from Streptomyces strains on cultures of several phytopathogenic fungi

2020 ◽  
pp. 879
Author(s):  
Daniel Alonso Pérez Corral ◽  
José de Jesús Ornelas Paz ◽  
Guadalupe Isela Olivas Orozco ◽  
Carlos Horacio Acosta Muñiz ◽  
Miguel Ángel Salas Marina ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Fungal Pathogens ◽  
Culture Medium ◽  
Plant Pathogens ◽  
Aerial Mycelium ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Fresh Culture Medium

Fungi and oomycetes are important plant pathogens that constantly attacked plants, thus compromising the production of foods worldwide. Streptomyces strains might be useful to control fungal pathogens by different mechanism. The in vitro antagonistic activity of non-volatile and volatile metabolites from four Streptomyces strains was evaluated over cultures of phytopathogenic fungi and oomycetes. The non-volatile compounds from Streptomyces strains significantly reduced (44.2 to 92.1%) the growth of aerial mycelium of pathogens. The volatile compounds (VOCs) from Streptomyces strains reduced both aerial mycelium (22.5 to 96.7%) and mycelium growing inside of culture medium (0.0 - 9.4%). The pathogens maintained their capacity to grow normally in fresh culture medium without antagonists after confrontations with antagonist VOCs. The analysis of VOCs by gas chromatography coupled to mass spectrometry revealed different kinds of VOCs included alcohols, aldehydes, ketones, esters, terpenes, terpenoids, thioethers, among others. The most abundant VOCs were trans-1,10-dimethyl-trans-9-decalol (geosmin), 2-methylisoborneol, 2-methyl-2-bornene, 1,4-dimethyladamantane, and 4-penten-1-ol, trifluoroacetate. The antipathogenic activity of nine pure VOCs that had been identified in cultures of the Streptomyces strains alone was evaluated in vitro against phytopathogenic fungi and oomycetes. Trans-2-hexenal was the most effective of these VOCs, inhibiting completely the growth of tested phytopathogens. The volatile and non-volatile compounds from Streptomyces strains effectively reduced the in vitro growth of phytopathogens and they might be used as biological control. Further studies are required to demonstrate this activity on open field conditions.

scholarly journals Natural compounds: A sustainable alternative for controlling phytopathogens

2018 ◽  
Author(s):  
María Fernanda Jiménez-Reyes ◽  
Héctor Carrasco ◽  
Andrés Olea ◽  
Evelyn Silva-Moreno
Keyword(s):  
Natural Products ◽  
Secondary Metabolites ◽  
Antifungal Agents ◽  
Phytopathogenic Fungi ◽  
Direct Application ◽  
Economic Losses ◽  
Infectious Agents ◽  
Active Compounds

Fungi are the primary infectious agents in plants causing significant economic losses in agroindustry. Traditionally, these pathogens have been treated with different synthetic fungicides such as hydroxianilides, anilinopyrimidines, and azoles, to name a few. However, the indiscriminate use of these chemicals has increased fungi resistance in plants. Natural products have been researched as a control, and an alternative to these synthetic fungicides since they are not harmful to health and contribute to the environment caring. This review describes plants extracts, essential oils, and active compounds or secondary metabolites as antifungal agents both, in vitro and in vivo. Active compounds have been recently described as the best candidates for the control of phytopathogenic fungi. When metabolized by plants, these compounds concentrations rely on the environmental conditions and pathogens incidence. However, one issue regarding the direct application of these preformed compounds in plants touch upon their low persistence in the environment, and their even lower bioavailability than synthetic fungicides. Hence the challenge is to develop useful formulations based on natural products to increase the compounds solubility facilitating thus their application in the field while maintaining their properties.

Essential oil vapours control some common postharvest fungal pathogens

2007 ◽  
Vol 47 (1) ◽  
pp. 103 ◽  
Author(s):  
M. Szczerbanik ◽  
J. Jobling ◽  
S. Morris ◽  
P. Holford
Keyword(s):  
Fungal Pathogens ◽  
Rhizopus Oryzae ◽  
Vapour Phase ◽  
Geotrichum Candidum ◽  
Fungal Resistance ◽  
Environmental Damage ◽  
Cinnamon Oil ◽  
Tea Tree ◽  
Alternative Means

Diseases caused by fungal pathogens cause substantial postharvest losses to most perishable food crops. Fungal diseases are currently controlled with fungicides; however, reliance on this single control strategy leads to problems such as environmental damage and fungal resistance to fungicides. There is increasing pressure from consumers to find more natural methods of disease control. A possible alternative to fungicides may be essential oils, which have been shown to inhibit the growth of several fungi and are seen as natural compounds. The present study examined the effect of the vapour phase of spearmint, tea tree, pine and cinnamon oils and an antifungal blend on the growth of eight common postharvest fungal pathogens growing in vitro. It was found that the antifungal, spearmint and tea tree oils controlled the growth of Botrytis cinerea, Fusarium solani, Colletotrichum sp., Geotrichum candidum, Rhizopus oryzae, Aspergillus niger and Cladosporium cladosporiodes more effectively than pine or cinnamon oil but were less effective against Penicillium digitatum. Antifungal, spearmint and tea tree oils appeared to reduce sporulation in P. digitatum, A. niger and R. oryzae and inhibited spore germination by A. niger. This work shows that the antifungal, spearmint and tea tree oil vapours may provide an alternative means of controlling postharvest pathogens. All of the oils had a fungistatic mode of action and their use would require the development of commercial treatment methods applicable throughout the postharvest handling chain.

scholarly journals Investigation of host-specificity of phytopathogenic fungi isolated from woody plants

2020 ◽  
pp. 155-160
Author(s):  
Andrea Zabiák ◽  
Györk Milán Károlyi ◽  
Erzsébet Sándor
Keyword(s):  
Host Specificity ◽  
Fungal Pathogens ◽  
Apple Tree ◽  
Weather Conditions ◽  
Phytopathogenic Fungi ◽  
Botryosphaeria Dothidea ◽  
New Host ◽  
Diplodia Seriata ◽  
New Hosts

Host-specificity is an important characteristic of fungal pathogens. Changing climate could create more appropriate environmental conditions for phytopathogens, thus formerly host-specify fungi could be able to colonize new hosts. Noxious plant pathogen fungi, which can infect several plant species are well-known worldwide. These genera may expand their range of hosts because of the appearance in new geographic areas due to climate change. This new exposure can result in serious problems in agriculture because of the lack of immunity. The susceptibility of apple tree was studied through testing pathogenicity in vitro with species isolated from walnut twigs and nuts, and identified by ITS sequences. Three of four tested species, Botryosphaeria dothidea, Diaporthe eres and Diplodia seriata colonized and necrotized the infected apple branches, while Juglanconis juglandina was not able to infect the twigs. Members of Botryosphaeriaceae were the most virulent, causing the largest lesions in the fastest way. This experiment draws attention to the threat of new host-pathogen connections, which can arise because of the favourable weather conditions and can spread between neighbouring cultures. 

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