Streptomyces sp. has been widely recognized as an important industrial microorganism due to its potential in the production of a wide range of secondary metabolites including antibiotics, antitumor agents, antiparasitic agents, and inhibitors. immunomodulatory and enzymes.
Some typical active ingredients and products from actinomycetes:
-Antibiotics: streptomycin, erythromycin, tetracycline, neomycin, chloramphenicol, vancomycin, gentamicin.
Antifungal drugs: nystatin, amphotericin.
Anti-cancer drugs: doxorubicin, bleomycin, mitomycin.
Immunosuppressive drugs: rapamycin.
-Herbicide: bialaphos.
Overview and potential application of actinomycetes in agricultural production
What is Streptomyces bacteria?
Actinomycetes (scientific name: Antinobacteria; English: Actinomycetes) are a group of true bacteria (Eubacteria) widely distributed in nature. Previously classified as Vegetative canopy (i.e. fungi), but are now classified as bacteria (Schizomycetes).
Classification of actinomycetes Streptomyces
Streptomyces is the largest genus of the phylum Actinobacteria and is a member of the clade Streptomycetaceae.
To date, more than 500 species of streptomyces have been described.
Like most other Actinobacteria, Streptomyces is a Gram-positive bacterium, with a genome with a high GC% rate. This bacterium is found mainly in soil and decaying vegetation.
Characteristics of actinomycetes Streptomyces
Streptomyces has a mushroom-like structure, so some people mistake Streptomyces for a fungus. Their branches have an arrangement of filamentous cells in a network called hyphae. They can metabolize various compounds including sugars, alcohols, amino acids and aromatic compounds by producing extracellular hydrolytic enzymes. Because of their large genes, their metabolism is also diverse, including hundreds of transcription factors that control gene expression, allowing them to meet specific needs.
Streptomyces produces spores, produces a characteristic odor, resulting from the production of geosmin during metabolism.
Streptomyces is widely studied and is best known as the genus of actinomyces (Actinomyces).
Streptomyces culture media
To isolate Streptomyces actinomycetes, people often use the disc agar method with specific media for actinomycetes such as GauseI, GauseII, Krasilnicov, and ISP systems.
Culture of Streptomyces bacteria on plate agar
The role of actinomycetes Streptomyces
Streptomyces is a common soil-dwelling organism and is an important decomposer. One of the most important characteristics of Streptomyces is the ability to form antibiotics. Of the current 8,000 antibiotics in the world, more than 80% are derived from actinomycetes.
The antibiotics derived from actinomycetes have quite broad spectrum of resistance ; It is a selective antibiotic.
The antibacterial ability of antibiotics is an important feature to classify actinomycetes. Many actinomycetes have the ability to synthesize 2 or more antibiotics with similar chemical structures and similar effects. The biosynthesis of antibiotics depends on a multi-gene regulation mechanism, in addition to the genes responsible for antibiotic synthesis, there are also enzymes responsible for the synthesis of precursors and cofactors.
Application of actinomycetes Streptomyces in agriculture
The use of antibiotics in cultivation is aimed at combating fungal diseases on vegetables and crops, against bacterial diseases, killing insects and weeds, and controlling plant diseases. born of the earth.
Compared with chemical drugs, the use of antibiotics in plant protection is both fast acting, easy to decompose, has high selectivity, low toxicity, does not pollute the environment, and also has the ability to inhibit the growth of pathogens. microorganisms are resistant to chemical drugs. Antibiotics and fermentation fluids of antibiotic strains are also used to treat seeds with the aim of destroying pathogens on the outside and inside of the seeds, killing diseases on the soil parts of the plant, and reducing the risk of disease. earthworm.
The antagonism between microorganisms in the soil is the basis of plant disease control measures. The presence of antagonistic actinomycetes in the soil markedly reduced the incidence of plant diseases. Usually an antagonistic actinomycete can inhibit a few pathogenic fungi, but there are broad-spectrum active species that can inhibit many soil-borne pathogens.
Not all antifungal activity in vitro are present in the soil (about 4 – 5%) but they have an important role in inhibiting pathogenic fungi and preventing the possibility of plant infection. This is the law of biological balance in nature. If the balance is lost, disease will immediately arise when there are pathogens in the soil.
Antifungal actinomycetes, in addition to secreting antibiotics, also act on the microflora through degrading enzymes. In addition, many actinomycetes also secrete plant growth substances as well as stimulate beneficial microflora in the rhizosphere.
In 2002, a strain of Streptomyces sp. was isolated in India. 201 has the ability to produce a new antibiotic, z – methylheptyl iso – nicotinate, which is resistant to many pathogenic fungi such as Furasium oxysporum, Furasium solani…
In Vietnam, we also use many antibiotic preparations for plant protection imported from China, Japan… and some actinomycete strains have been isolated with the ability to fight bacteria. Pyricularia oryae cause rice blast and F. oxysporum cause root rot in plants. However, the use of antibiotics in the field of plant protection in our country is still very low due to farming practices accustomed to using certain pesticides.
Read more : >> Preventing diseases that damage pepper when the weather changes
Follow Wikipedia, FistaNet
