Abstract:

We review advances in understanding the production, eco-physiological roles, and related regulatory mechanism of green leaf volatiles (GLVs). GLVs are six-carbon aldehydes, alcohols and esters derived from the hydroperoxide lyase branch of the octadecanoic acid pathway in plants. Besides leaves, other tissues such as root, stem, fruit, and seed are also reported to be capable of producing the GLVs regulated at the levels of transcription and post-transcription in plants. GLVs composition and amounts are influenced by the developmental stage and growth environment such as seasonal change in a given plant. In addition, the formation of GLVs can be induced by biotic stress such as insect attack, inoculation of pathogenic bacteria and inhabitation of beneficial fungi, as well as abiotic ones such as nitrogen deficiency. Although GLVs are primarily recognized as important contributors to unique flavors, they also play important roles in direct and indirect defense responses. They not only inhibit the reproduction of bacteria, fungi and insects, but also induce the synthesis of various defensive compounds. They can also prime different signal induction pathways. The potential roles that GLVs played in the quality formation of Chinese herbs, especially genuine ones, are discussed based on their wide distribution and multi-layered defensive roles in plants. It is necessary and urgent to carry out related research on GLVs in Chinese herbs for their sustainable and green development.

Key words: Chinese medical herbs, defense response, green leaf volatiles, induced effect, quality formation