Research progress on active amino acids of pesticides from natural sources
Natural products have always been an important source of drugs and drug lead compounds. According to the 2014 global pesticide sales statistics, natural product based pesticides accounted for approximately 21% of total sales over the past 60 years. If pesticides developed based on natural products are included, this proportion will reach 53%, and some researchers believe that this proportion may even reach 70%.
Proteins are high polymers composed of amino acids with diverse physiological activities, playing an important role in life activities. The 22 basic amino acids that make up proteins, including selenocysteine and pyrrolic lysine, are called protein amino acids. Non protein amino acids refer to compounds containing amino and carboxyl groups other than protein amino acids. There are thousands of non protein amino acids in nature, of which more than 250 come from plants and others from microorganisms, algae, and animals. Some compounds with pesticide activity have been discovered from these natural amino acids, and many pesticide varieties have also developed natural amino acids as building blocks. One important amino acid, phosphinothricin, has been developed for use as a herbicide. Therefore, it is of great significance to search for amino acids with pesticide activity from nature. This article mainly summarizes the natural source amino acids with pesticide activity reported in literature in the past 30 years, including structural types, sources, pesticide activity, and some mechanisms of action, hoping to provide reference for the research and development of new pesticides.

Currently, due to people’s attention to environmental and food safety issues, the development of efficient, safe, and environmentally friendly new varieties of pesticides is receiving increasing attention. Many naturally occurring amino acids have strong control effects on weeds, harmful fungi, bacteria, and pests. Some have been developed into commercial agricultural products, such as glyphosate, which is developed through chemical synthesis based on L-phosphomycin (10) and is one of the most successful herbicides developed in recent years with microbial natural products as the lead. The coronamycin (33) produced by Pseudomonas syringae has physiological functions such as regulating plant growth, increasing chlorophyll content, and enhancing plant stress resistance at low concentrations. China Agricultural University and other institutions have successfully developed it as a plant growth regulator. There are also some natural amino acids with good application prospects in agricultural production, such as natural protein amino acids methionine (1), lysine (2), tryptophan (3), leucine (4), and tyrosine (5), which have feedback inhibition through metabolic pathways to produce weed control effects. They can be used for biological control of parasitic weeds such as Leymus chinensis and Egyptian goldenrod. Some non protein amino acids produced by plants can act as allelopathic substances to inhibit their surrounding competitors, such as acacetin (6), δ – hydroxyleucine (11), L-coumarin (14), L-DOPA (20), β – (3-isoxazolin-5-on-2-yl) – alanine (24), and mimosa (26) produced by leguminous plants, which are all amino acid allelopathic substances that can selectively inhibit the growth of other plants with little impact on leguminous and gramineous plants. Therefore, they can be developed as herbicides for agricultural production. The tyrosine (19) secreted by the roots of fine leaved fescue is also a strong and effective allelopathic substance, which has growth inhibitory effects on various plants at concentrations of μ mol/L. It can be used as a broad-spectrum herbicide in agricultural production. 5-ALA (46) is involved in the growth regulation process of plants and has physiological activity similar to phytoestrogens. It can be used as a plant growth regulator in agricultural production. Natural amino acids are abundant in source and have a wide range of pesticide activities, but the mechanisms of action of most of these compounds need to be further studied to expand their applications in the field of pesticides.