Terpene production by bacteria and its involvement in plant growth promotion

Abstract

Plant Growth Promoting Bacteria (PGPB) enhance growth and promote yield in several cultivated species mainly by increasing the root area active in water and mineral uptake, as well as by inducing mechanisms of stress alleviation at the tissue level. Such beneficial effects are explained via production of secondary metabolites including terpenes. Terpenes are a large class of chemicals which are synthesized via the mevalonic acid (MVA) pathway, although in plant cells there is another pathway, via methyl erytritol phosphate (MEP), localized in plastids. The PGPB produce (or induce the plant cell production of) several terpenes that are involved in the host enhancement of growth and yield, as well as in stress alleviation: through the action of phytohormones (gibberellins and abscisic acid), membrane-related sterols, and defence-related compounds (volatiles and sesqui- and di-terpenic phytoalexins).