There is huge room for the development of biological source fungicides
2020-03-12
Biofungicide is a class of biologically active substances closely related to organisms (including plants, microorganisms such as fungi, bacteria, viruses, and insects, etc.). Most of the biogenic fungicides are substances with anti-pathogenic microorganisms that exist in plants or are induced by external stimuli or produced by microbial degradation and metabolism. According to different biological sources, fungicides can be divided into three categories: antibiotics, natural products and plant defensins. Antibiotic The original meaning of antibiotics refers to chemical substances produced by microorganisms during their metabolism, which can inhibit the growth and activity of other microorganisms at low concentrations, and even kill other microorganisms. With the development of research and production of antibiotics. Its meaning has been added again. Characteristics of the antibacterial effect of agricultural antibiotics: (1) Strong selectivity, because various microorganisms have fixed structures and metabolic methods. The mode of action of various antibiotics is also different, so an antibiotic only has antibacterial effect on certain types of microorganisms, that is, it is selective. (2) Low toxicity, the toxicity of antibiotics to human body, animal and plant tissues is far less than its toxicity to pathogenic bacteria. (3) High safety. Because antibiotics have the above-mentioned selective toxicity and fast biodegradation, they generally do not infect the environment. (4) Most of them have systemic activity and therapeutic and protective effects. (5) It is easy to cause drug resistance. Due to the high selectivity of antibiotics, under the action of pathogenic bacteria, in addition to suppressing or killing a large number of sensitive bacteria, there are often some strains that adjust or change their metabolic pathways, changing from sensitive bacteria to insensitive bacteria. develop drug resistance. (6) The drug effect is unstable and the duration of effect is short. Because the microorganisms that produce antibiotics are also prone to mutation, the drug effect of antibiotics is sometimes unstable. (7) The application cost is high. Natural product As natural products of agricultural fungicides, they refer to organic substances derived from plants, and these organic substances originally exist in plants, rather than being produced by external stimuli. The natural products that exist in plants and make the plants themselves have disease resistance can be summarized as follows: (1)Carboxylic acids, such as indole acetic acid, Gibberellic Acid, etc.; (2) Amino Acids, such as histidine, methionine, canavanine, etc.; (3) Phenols, such as catechol, hydroxybenzene Formic acid, etc.; (4) phenolic acids, such as chlorogenic acid; (5) lactones and coumarins. Such as 3-ethylene acid lactone. (6) tannins; (7) acetylenic compounds, such as capchenin, etc.; (8) ketones, such as 5-hydroxy-l,4-diquinone; (9) oxalone; (10) benzo Oxazolone etc. These compounds do not have a direct poisoning effect on the pathogenic bacteria that infect plants, and some of them make plants develop disease resistance by changing the metabolism of the host. Phytodefensins The healthy growth and development of plants is guaranteed by drugs on the one hand, and on the other hand, plants themselves also have a kind of stress resistance. Phytodefensin (or phytodefensin) is a plant product formed due to increased enzyme activity in plants, and is a type of low-molecular organic matter in the active defense system of plants. This substance is generally believed to inhibit the development of pathogenic microorganisms in the damaged tissues of plants and is produced by external stimuli. The so-called exogenous stimuli include the invasion of fungi, bacteria and viruses, changes in nutrition, mechanical damage, ultraviolet light exposure, and the treatment of certain chemical substances. Plant defensins are mostly derivatives of furan, sterol, coumarin, isocoumarin, phenols and shikimic acid and other compounds. Future development Chemical pesticides not only prevent pests, weeds and rodents, but also have a certain impact on the quality and safety of agricultural products and the safety of the ecological environment. In recent years, as the country has put forward higher requirements for the green and high-quality development of agriculture, it is necessary to ensure national food security and the effective supply of important agricultural products, promote independent innovation in areas such as green inputs, continue to maintain negative growth in pesticide use, and advocate the establishment of resource conservation. Model and environment-friendly ecological civilization and green production. This provides a good opportunity and huge space for the development of biological pesticides.
