Bioactive Molecules in Plant Defense (original) (raw)

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Present control technologies of plant pathogenic fungi decouple the pathogen's life cycle mainly in two points of ontogeny, either by destroying spores prevent the infection or inhibit the biotrophic thallus, thus anticipating the formation of new infective propagules. Although, nowadays, the only tool for credible control of cultivated plants is the use of synthetic chemicals, the calculability of yield sureness has been worldwide threatened by the emergence of acquired tolerance to this group of pesticides as well as anxious feelings for their undesirable side effects. This situation urges the development of efficient alternative control agents, as threatening the net return even 10% disease incidence can cause economic loss. One approach to discover newer antimicrobial compounds is to search for their presence in natural sources exploiting the defense strategies of plants against their pathogens. Contrary to phytoalexins that are synthesized de novo after the plant is exposed to microbial attack, i.e., being produced in response of elicitors or stressors, the phytoanticipins are not formed in the tissue or released from preexisting plant constituents. These substances are plant antibiotics presented in tissue prior to infection, serving as the basis of pest tolerance. Several thousands of such molecules of different structure have been identified; however, few of them met practical application. In this chapter, we focus on constitutive mechanisms that might be used for controlling phytopathogenic fungi with special regard to organic substances, which might serve either as botanical fungicides or as lead compounds for molecular design. Consequently, the introduction of alien phytoanticipins and precursors of phytoalexins into the proper host/ parasite system can represent a prospective tool for disease management. We summarized the results and experiences of past three decades searching for candidates for biofungicides useful in pest management practices. The efficacy of over 100 plant species used as either spices or preparations in traditional medicine or culinary was demonstrated in vitro against 25 phytopathogenic fungi, and possible use of promising candidates was discussed.

Phytoanticipins: The Constitutive Defense Compounds as Potential Botanical Fungicides

2019

Present control technologies of plant pathogenic fungi decouple the pathogen's life cycle mainly in two points of ontogeny, either by destroying spores prevent the infection or inhibit the biotrophic thallus, thus anticipating the formation of new infective propagules. Although, nowadays, the only tool for credible control of cultivated plants is the use of synthetic chemicals, the calculability of yield sureness has been worldwide threatened by the emergence of acquired tolerance to this group of pesticides as well as anxious feelings for their undesirable side effects. This situation urges the development of efficient alternative control agents, as threatening the net return even 10% disease incidence can cause economic loss. One approach to discover newer antimicrobial compounds is to search for their presence in natural sources exploiting the defense strategies of plants against their pathogens. Contrary to phytoalexins that are synthesized de novo after the plant is exposed to microbial attack, i.e., being produced in response of elicitors or stressors, the phytoanticipins are not formed in the tissue or released from preexisting plant constituents. These substances are plant antibiotics presented in tissue prior to infection, serving as the basis of pest tolerance. Several thousands of such molecules of different structure have been identified; however, few of them met practical application. In this chapter, we focus on constitutive mechanisms that might be used for controlling phy-topathogenic fungi with special regard to organic substances, which might serve either as botanical fungicides or as lead compounds for molecular design.

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Induced plant secondary metabolites for phytopatogenic fungi control: a review

Pathogenic fungi constitute one of the main infectious agents in plants, causing alterations during developmental stages including post-harvest. Phytopathogenic fungi are controlled by synthetic fungicides; however, the use of these is progressively restricted due to both, the harmful effects of pesticides on the environment and human health and the appearance of highly resistant fungal strains. Therefore, there is a great demand for novel natural fungicides. Higher plants are rich source of bioactive secondary metabolites of wide variety such as tannins, terpenoids, saponins, alkaloids, flavonoids, and other compounds, reported to have in vitro antifungal properties. Thus, secondary metabolites with antifungal activity represent an alternative for achieving a sustainable control of phytopathogenic fungi and to reduce the heavy reliance of synthetic pesticides used to control them. Plant antifungal metabolites may be preformed inhibitors that are present constitutively in healthy pl...

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Plant Bioactive Chemicals for Anti-Fungal and Biofungicidal Potencies: A Review

International Journal of Advanced Academic Research, 2021

Fungi are the major infectious agents of plant diseases causing significant economic loses to farmers and nations alike. These plant fungal diseases are mostly treated with synthetic chemicals. However, indiscriminate use of these chemicals has increased fungi resistance in plants; constitute residues in plants, their fruits and the environment, and consequently has negative impact on the health of consumers as well as the eco-system. This has led to the drive to search for plant bioactive chemicals which are biodegradable and eco-friendly. Organic products have been researched for use as safe alternative to the use of synthetic chemicals for use and management of plant diseases. The products are not harmful to the health of man and his environment. This paper reviews the bioactive compounds of plants for anti-fungal and bio-fungicidal potencies for plant disease management and the mode of actions of these compounds. From the findings of this study, there are myriads of plant specie...

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Natural compounds: an effective and eco-friendly strategies for controlling and combating plant pathogens

Notulae Botanicae Horti Agrobotanici Cluj-Napoca 51(1):12991, 2023

Currently, the management of phytopathogenic agents is an ongoing challenge globally, as they cause major damage in agricultural plantations. However, the use of synthetic pesticides currently in use has negative effects on the environment and on the living organisms that develop their life cycle in these habitats. For this reason, research in the last decade has led to the identification and exploitation of natural compounds with important antifungal properties as natural alternatives to combat and control pathogens. This review is based on the description of plant extracts, essential oils and natural compounds with important anti-fungal properties. However, their direct application to plants is difficult, because their adhesion and persistence in environmental conditions does not allow this fact. The current challenge is to develop formulations based on natural compounds that retain their properties over time in order to be applied to agricultural crops.

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