β-methoxyacrylates fungicides are derived from the natural antibiotic strobilurin A with bactericidal activity, so they are also called strobilurins fungicides. Since Musilek et al. discovered the bactericidal activity of a mushroom called Strobilurin in 1969, scientists have achieved great success in the development of this type of fungicide after more than 20 years of structural optimization research. Syngenta and BASF first registered Amicida (azoxystrobin) and Tribeta (acetostrobin) in Germany in 1996 respectively for the prevention and treatment of wheat powdery mildew and leaf blight. By 2000, only Amicida Dajiu has registered the control of more than 400 fungal diseases on more than 100 crops around the world. Amicida and Tribe have set a historical record of consecutive annual sales of more than $400 million for a single variety. The sales of a single variety rank third and fifth respectively after glyphosate and imidacloprid. In terms of fungicide development A new milestone has been set in history after triazole fungicides. Methoxyacrylate fungicides have outstanding advantages: ① It is highly selective, safe for almost all crops and ecology, and meets human requirements for the environment; ② It has particularly broad-spectrum and efficient antibacterial activity, and is effective against oomycetes. , Ascomycetes, Basidiomycetes and Deuteromycetes all have high bactericidal activity, which is in line with the comprehensive prevention and control strategy; ③ It has protective, eradication, anti-sporulation and therapeutic effects, which is in line with the prevention-oriented plant protection policy; ④ It has good endogenous Among them, amicida is better distributed evenly in plants than triazole fungicides and can diffuse through the gas phase in the plant canopy; ⑤ It has a unique target and is different from other existing fungicides. Fungicides have no cross-resistance; ⑥ It can significantly delay plant aging, promote plant growth, and improve the yield and quality of agricultural products.
The unique mechanism of action of methoxyacrylate fungicides determines the type and effect of preventing and treating plant diseases, which not only depends on the physical, chemical and biological properties of the agent itself, but also depends on the agent-pathogen-host of interaction. Methoxyacrylate fungicides mainly act on the mitochondrial respiration of fungi, destroying energy synthesis, thereby inhibiting fungal growth or killing germs. The agent binds to the Q0 site of Cytb in complex III (Cytbc1 complex) in the mitochondrial electron transport chain, blocking the flow of electrons from the Cytbc1 complex to Cytc. Therefore, methoxyacrylate fungicides or Strobilurins are also called Q0 inhibitors, or Q0Is for short. Recently, it was discovered that the mechanism of action of the oxazolidinones imidazolin and famoxadone also inhibits the Q0 site, so these two fungicides are also classified as methoxyacrylates. The adaptive biological evolution of fungi to disruption of electron transport in the respiratory chain is the existence of an alternative respiratory pathway. There is only one key alternative oxidase (AOX) complex in the alternative respiratory pathway. AOX has intrinsic or inducible expression in different fungi. Therefore, methoxyacrylate fungicides are less effective against fungi with intrinsic AOX expression, such as Botrytis cinerea and banana black spot fungi. The mechanism of AOX-induced expression in fungi is relatively complex, but it is known that increased superoxide radical concentration in some fungal cells can induce AOX expression. Therefore, superoxide radical scavengers can enhance or prolong the antibacterial activity of methoxyacrylate fungicides. Likewise, substances such as ()flavonoids are known to be present in certain plant metabolism processes. These substances have the effect of inhibiting AOX activity. Therefore, methoxyacrylate fungicides can show higher antibacterial activity on plants than in vitro against some fungi.
In the early stages of the development and use of methoxyacrylate fungicides, research on the risk of resistance was considered to be a moderate risk. In fact, after two years of application of this type of fungicide, resistance develops and the control effect decreases significantly.
For example, there were reports on the occurrence of powdery mildew resistance in wheat and barley one year after the practical application of acetostrobin. By 2000, drug-resistant conidia had accounted for 10% of the field pathogen populations in northern Germany, northern France, and the United Kingdom. 2 to 99. In 1999, resistant strains of powdery mildew and downy mildew were also detected in Japan on cucumbers and melons. However, wheat leaf spot, brown rust and net spot pathogens develop resistance relatively slowly. Currently, in addition to being used as single agents, methoxyacrylate fungicides are often mixed with other types of fungicides, which will become the further development trend of this type of fungicides. Bayer developed a compound of "trifloxystrobin + propiconazole" in 2001; Syngenta also launched a compound of "azoxystrobin + propiconazole" in 2004.
So far, there have been thousands of invention patents related to methoxyacrylate fungicides, and 8 varieties have been commercialized, including azoxystrobin, tristrobin, and trichostrobin. esters, phenoxystrobin, picoxystrobin, pyraclostrobin, fluoxastrobin and tristrostrobin, etc. There are also many varieties that are in development before entering the market.