Genomics of Rubber Biosynthesis in Hevea brasiliensis

The Hevea brasiliensis rubber tree is the largest commercial producer of natural rubber. The ability to synthesize a naturally occurring polymer is one of the main attractions of studying latex rubber biosynthesis. Natural rubber consists of high molecular weight cis-polyisoprene, a branch product of the isoprenoid network, which is synthesized by sequential condensations of isopentenyl diphosphate (IPP). To date, genomic technologies have enabled the generation of Hevea transcriptomes, draft genomes and rubber particle proteomes for a number of key tree clones (or cultivars). These have contributed significantly to the molecular genetics of genes encoding the mevalonate (MVA) and methylerythritol 4-phosphate (MEP) pathways of IPP synthesis, including rubber transferase candidates that participate in the final steps of cis-polyisoprene formation. Rapidly developing sequencing technologies will continue to provide opportunities to yield new insights into rubber biosynthesis. This chapter discusses the prospects of furthering genomics analysis of rubber biosynthesis in the following areas: regulation of pathways supplying and utilising IPP for rubber and non-rubber isoprenoids, characterization of rubber particle proteins in relation to molecular weight distribution and lipid droplet membrane proteins, and the potential benefits of haplotype analysis of rubber biosynthesis pathway genes for genomics-driven breeding.