Agricultural antibiotics

An antibiotic used in agricultural control of plant diseases. Antibiotics are substances produced by microorganisms. It is usually isolated from its metabolites, and some can also be artificially synthesized. It can inhibit or kill other microorganisms, and some can kill insects and kill plants. [A brief history] Antibiotics began in 1928 when penicillin was found in Afleming, England. Because it has excellent effects on certain bacteria in the human body, it induces people to vigorously seek new antibiotics. Soon, antibiotics such as chloramphenicol, chlortetracycline and streptomycin were discovered. In the application of antibiotics, research outside the medical field began in the 1940s. In 1944, Brown and Boyle applied crude penicillin to effectively control crown gall disease caused by several bacteria. In 1946, Upjohn found that antibiotic ketone (cycloheximide) has a high antibacterial activity against plant fungi, and later people discovered streptomycin, chloramphenicol, etc. for certain plant bacteria and fungi. The disease also has a good effect. This has led to the recognition that antibiotics can control plant diseases. So far, although about 900 kinds of antibiotics have been identified, there are only more than 10 kinds of practical value in agriculture due to many factors such as instability, phytotoxicity, high cost or toxicity to warm-blooded animals. Japan has made significant progress in the study of agricultural antibiotics. In 1955, the first discovery of quercetin in Japan and the successful study of Kasugamycin in 1963 by Japan's Beixing Chemical Industry Co., Ltd. have been widely used for the control of rice blast. In 1964, the polyoxymycin developed by Beixing Chemical Industry Co., Ltd. and the effective mycin developed by Takeda Pharmaceutical Industry Co., Ltd. in 1972 were also widely used in the prevention and control of rice sheath blight. In the late 1970s, Takeda Pharmaceutical Co., Ltd. successfully developed midomycin to effectively control powdery mildew of cucumber, melon, rose, strawberry, tomato, barley, tobacco, grape, pea, apple, etc. After Japan, China has separated and developed antibiotics that are identical or similar to those of Japanese saponins, kasugamycin, polyoxymycin, and tyrosin, namely, Chinese quercetin, geranol, and polymycins. Jinggangmycin. In 1982, the Institute of Plant Protection of Jilin Academy of Agricultural Sciences successfully developed phallpenemycin for seed dressing control of sorghum smut, smut, wheat smut, net smut, and granules. disease. [Category Type] Bacteria, fungi and actinomycetes can produce antibiotics, of which actinomycetes produce the most antibiotics. Many of the important agricultural antibiotics that have been widely used are isolated from the actinomycete Streptomyces. Most of the metabolites of these microorganisms are complex in chemical structure, some are not a single compound, but a mixture of multiple components or homologues. In order to overcome the shortcomings of certain metabolites themselves: instability, phytotoxicity to plants, high toxicity to warm-blooded animals, and convenience for processing and use, certain commercial varieties are not isolated metabolites themselves. It exists alone, but is made into various salts. For example, polymycins belong to peptide pyrimidine nucleoside compounds, and its main components are polyoxin A and polyoxin B, but in fact it consists of 14 homologues from A to N. . Jinggangmycin is a glucoside (or aminocycloalcohol) compound in which A is the highest active ingredient, but it consists of six components. The principalmycin is composed of dehydrated ketone, isoproterone, bacteriocin, natamycin and benzoic acid. The chemical structures of scutellarin and serotonin belong to a complex base, and their commercial products are present in the form of benzylaminobenzenesulfonate and hydrochloride, respectively. [Performance] 1 The commercial agricultural antibiotics are all solid, generally stable in nature and low or moderately toxic to warm-blooded animals. The existing antibiotics are mainly fungicides, and there are not many antibiotics with insecticidal and herbicidal effects, and the antibiotics in the fungicides are mainly fungicides. 2 high efficiency. When applied at a very low concentration, a satisfactory control effect can be obtained. The concentration of the prin fom seed treatment was 50 mg/L. Spraying 8 kg of this liquid per 100 kg of seeds has a high control effect on cereal smut. The effective spraying concentration of other agents is generally 20-50 micrograms/kg; 3 has good systemic therapeutic activity. The drug is easily absorbed by the plant and transmitted in the body, and has strong ability to withstand rain. Generally, the rain is 3 to 5 hours after application, and has no effect on the efficacy; 4 is selective; 5 because the residual effect period is short, the use concentration is low, and the dosage is small. Safe for people, animals and plants. The method of administration of the medicament, except for the use of principalmycin for seed treatment, is applied by spraying. The preparation of such a medicament is mainly composed of a low concentration of wettable powder (2 to 6%) and a powder (0.16 to 3%), and is also processed into a low concentration of emulsifiable concentrate (2% 10%) and a liquid preparation (2 to 5%). ). 6 Like chemical fungicides, agricultural antibiotics have different mechanisms of action and can generally be divided into three mechanisms of action: inhibition of energy production, interference with biosynthesis, and destruction of cell structure. Streptomycin, oxytetracycline and chlortetracycline inhibit biooxidation and interfere with the respiration of pathogens, making them less energetic to sustain life. Actinomycin and blasticidin interfere with the binding of ribonucleic acid to amino acids and inhibit protein synthesis. Polyoxygenase inhibits urinary nucleoside phosphate-N-acetylglucosaminyltransferase, making it impossible for glucosamine to enter the cell wall for chitin biosynthesis. Jinggangmycin makes mycelial mycelial branching abnormal