Researchers from Tokyo University of Science developed a structurally similar compound to menthol which boosts the plant's immune system against herbivore pests.
Terpenoids are natural chemicals released by plants that can serve as airborne signals to activate defense-related genes in nearby plants of the same species. The researchers chemically modified the terpenoid compound menthol by attaching amino acids to produce six derivatives. They wanted to see if these modified compounds are more effective than unmodified menthol in activating plant defense mechanisms. The researchers then applied these modified compounds in soybean leaves and found that only valine methyl ester (ment-Val) outperforms menthol.
Further experiments showed that ment-Val solution boosted the expression of defense-related genes of soybeans for three days, and the second spraying on the fourth day boosted the expression of these genes again. The researchers also found that men-Val could also increase the gene expressions of defense-related genes on other crops such as maize, tobacco, and peas.
The study showed that ment-Val is a good alternative to chemical pesticides that farmers use. It is more eco-friendly and has good shelf life making it useful in the fields of agriculture and horticulture.
(Source: Crop Biotech Update, International Service for Acquisition of Agri-Biotech Applications.