Biosynthetic mechanisms of natural rubber and polyisoprenoids and perspectives for their metabolic engineering

Abstract

Isoprenoids are the most structurally diverse natural organic compounds, with more than 50,000 primary and secondary/specialized metabolites. The common precursor of isoprenoids is 5-carbon isopentenyl diphosphate (IPP) or its isomer dimethylallyl diphosphate. In addition, isoprenoids with a wide range of carbon numbers are biosynthesized from linear oligoprenyl diphosphates or polyprenyl diphosphates, formed by the sequential condensation of IPP, as hub intermediates. Natural rubber (NR), is the most industrially important polyisoprenoid because its unique physical properties are suitable for manufacturing tire. Currently, most of NR used in rubber industry is obtained from latex of the Para rubber tree (Hevea brasiliensis), cultivated in tropical and subtropical countries. To meet the ever-increasing demands for NR, metabolic engineering of H. brasiliensis to enhance the NR productivity and synthetic biology to establish NR bioproduction system in alternative species are desired. Here, I review recent progress in elucidation of the biosynthetic mechanisms of NR and related polyisoprenoids in plants and future perspectives on metabolic engineering for polyisoprenoid bioproduction.