Plants are the living organisms best able to produce a wide variety of chemical compounds.The biosynthesis of these compounds is well regulated, and they are distributed within the plants to play distinct biological roles. Some of these chemicals have an important role in the protection of plant as, unlike animals, plants can not escape from their predators. Cyanogenic glucosides (α-hydroxynitrile glucoside) are an example of such a class of chemical defense compounds, and they are found in a large number of plant species. They protect the plant against herbivores through a bioactivation me hanism that involves specific β-glucosidases. If plant tissue is disrupted, cyanogenic glucosides come into contact with these β-glucosidases and are hydrolyzed, which results in the release of hydrogen cyanide gas.
The work reported in this thesis is focused on the β-glucosidases that activated hydroxynitrile glucosides in the model plant Lotus japonicus. The work highlights how closely related β-glucosidases have evolved distinct substrate specificities and differential expression patterns to serve distinct physiological and ecological roles.