{"id":36350,"date":"2024-09-06T00:01:57","date_gmt":"2024-09-06T04:01:57","guid":{"rendered":"https:\/\/beyondpesticides.org\/dailynewsblog\/?p=36350"},"modified":"2024-09-05T16:30:37","modified_gmt":"2024-09-05T20:30:37","slug":"review-of-biofungicides-highlights-feasibility-of-alternatives-to-hazardous-pesticides-in-organic-agriculture-and-land-management","status":"publish","type":"post","link":"https:\/\/beyondpesticides.org\/dailynewsblog\/2024\/09\/review-of-biofungicides-highlights-feasibility-of-alternatives-to-hazardous-pesticides-in-organic-agriculture-and-land-management\/","title":{"rendered":"Biofungicides Show Promise in Agriculture and Land Management, Study Finds"},"content":{"rendered":"

(Beyond Pesticides<\/em>, September 6, 2024) A literature review in the Internal Journal of Molecular\u00a0<\/span><\/span><\/a><\/em>Sciences<\/em><\/a> provides<\/span>\u00a0promising insights into biofungicides as a \u201csustainable and economically viable alternative\u201d to synthetic fungicides in expanding organic agriculture. The authors note that organic \u201c… is the most sustainable response to current crises of all kinds, as it can better anticipate and prepare for crises and create long-term equity and resilience in food systems.\u201d The authors point out that fungal infections in crops are estimated to account for 20-40% of failures annually, and understanding how to control such agricultural diseases will be crucial to meeting the needs of a growing global population. Organic farmers and land managers note that biological tools can be integrated into practices that work with the ecosystem, rather than be utilized as \u201csubstitute\u201d products or controls with practices that ignore soil health and beneficial organisms that enhance biodiversity and provide ecosystem services<\/span><\/span><\/a> (see\u00a0here<\/a> and<\/span>\u00a0here<\/span><\/span><\/a>).<\/span><\/p>\n

Conducted by researchers in Mexico, the review examines data on biosynthesis (how plants create their own fungicide, known as secondary metabolites or SMs); the mechanisms of action of secondary metabolites against phytopathogenic (plant-killing) fungi; extraction techniques and biofungicide formulations; the biological activity of plant extracts on phytopathogenic fungi; and an overview of the current regulation and use of biofungicides in agriculture.<\/span><\/p>\n

According to the authors, many plants can synthesize one or more of several types of secondary metabolites (SMs) that create very specific conditions. SMs can be categorized into groups based on their chemical structure and biological activity: terpenes (including volatile compounds, sterols, and carotenoids), polysaccharides, phenolic compounds, phytoalexins (sulfur-containing compounds), alkaloids (nitrogen-containing compounds), flavonoids, and hydrocarbons. These compounds are often specific to a plant genus or family and often produced in small amounts. Given their natural origins, they are environmentally friendly with a short environmental lifespan that does not pollute soil and water. It is believed that SMs can even create a microclimate by slowing respiration and thereby protecting the plant during unfavorable conditions.<\/span><\/p>\n

Because the targeted biofungicides come from natural rather than synthetic ingredients, the authors cite research indicating limited persistence with a reduced half-life in the environment when used. The article notes that while not always harmless to other plants and organisms, plant-based chemical compounds can impact nontarget organisms, but are less toxic than synthetic pesticides. Depending on the plant source and the concentrations used, biofungicides have little influence on the growth, survival, development, and reproduction of other organisms. The review continues and notes that biofungicides exhibit \u201cno residual hazards, and minimize \u201cthe pollution of soil, water, and the atmosphere\u2026 and finally, they promote a reduction in health problems in farmers, such as chronic degenerative diseases of the skin and respiratory tract associated with the use of synthetic pesticides.\u201d (See here<\/span><\/span><\/a> for authors\u2019 citations). Health and environmental advocates note that synthetic fungicides are not only associated with adverse\u00a0<\/span><\/span><\/a>effects<\/a> on<\/span> health and the environment but also precipitate resistant fungi that threaten health<\/span><\/span><\/a> on a global scale. (See Beyond Pesticides\u2019 reporting on antimicrobial<\/span><\/span><\/a> and\u00a0<\/em>fungal<\/em><\/a> threats<\/em><\/span>\u00a0here<\/span><\/span><\/a>, here<\/span><\/span><\/a>, and here<\/span><\/span><\/a>). <\/em><\/span><\/p>\n

Researchers identify three SM primary types: terpenes and terpenoids, alkaloids, and phenolic compounds that are produced via four different mechanisms: the shikimic acid pathway, the malonic acid pathway, the mevalonic acid pathway, and the non-mevalonate (MEP) pathway.<\/span><\/p>\n

Terpenes
\n<\/strong><\/span>Research shows that due to their lipophilic nature, terpenes can work against fungi by infiltrating the fungal cell membrane and destabilizing the cell. Terpenes can also destroy mitochondria, the part of the cell responsible for energy production, and induce cell death by cellular respiration and oxidative phosphorylation or inhibition of electron transport in the mitochondrial electron transport chain.<\/span><\/p>\n

Phenolic Compounds
\n<\/strong><\/span>Researchers hypothesize that phenolic compounds can depolarize [neutralize] cellular and mitochondrial membranes of fungi, impairing the ion gradients and eventually causing cell death. Phenolic compounds can also inhibit key enzymes necessary for proper functioning of the biological system. It has also been demonstrated that phenolic compounds can modulate gene expression, which can alter growth, development, and reproduction of fungi.<\/span><\/p>\n

Alkaloids
\n<\/strong><\/span>Alkaloids have been known to impair fungal gene replication and transcription by infiltrating the fungus\u2019 DNA. They can also disrupt ion gradients in cell membranes by creating ion channels, leading to cell death. Alkaloids can also attach to proteins in the fungal organism, which prevents them from interacting with a plant\u2019s receptors and prevents colonization and infection by the fungus.<\/span><\/p>\n

The research also highlights that certain biofungicides operate similarly to synthetic fungicides due to a chemical structure akin to fungi\u2019s naturally occurring nucleic acids, which prevent the proper performance of fungi biological functions, such as acylalanines which inhibit ribosomal RNA synthesis. Researchers identify extraction methods using specific solvents via conventional and unconventional techniques. Primarily, extraction is done using solvents and either heating and\/or mixing. The type of solvent used depends on the type of compound to be extracted and largely determines the efficiency of the extraction. According to researchers, the polarity of the desired product is the most important factor determining which solvent should be used for extraction. Conventional extraction methods include the Soxhlet extraction, maceration, and hydrodistillation, while unconventional methods include ultrasound-assisted extraction, pulse electric field extraction, enzyme-assisted extraction, microwave-assisted extraction, pressurized liquid extraction, and supercritical fluid extraction.<\/span><\/p>\n

The authors highlight several techniques that avoid using solvents (hydrodistillation) or reduce the use of solvents (enzyme-assisted extraction and pressurized liquid extraction) as more environmentally responsible and call for additional considerations when selecting solvents: \u201cenvironmental safety, human toxicity, and financial viability.\u201d Extract-based biofungicides in agricultural systems offer significant advantages to farmers, including enhanced food security, reduced presence of phytopathogens, improved (crop) product quality, and the potential for higher market prices for organic products. Some examples the authors cite of significant phytopathogenic fungi and effective biofungicides include:<\/span><\/p>\n