Molecular Mechanisms of Natural Rubber Biosynthesis

Abstract

Natural rubber (NR), principally comprising cis-1,4-polyisoprene, is an industrially important natural hydrocarbon polymer because of its unique physical properties, which render it suitable for manufacturing items such as tires. Presently, industrial NR production depends solely on latex obtained from the Pará rubber tree, Hevea brasiliensis. In latex, NR is enclosed in rubber particles, which are specialized organelles comprising a hydrophobic NR core surrounded by a lipid monolayer and membrane-bound proteins. The similarity of the basic carbon skeleton structure between NR and dolichols and polyprenols, which are found in most organisms, suggests that the NR biosynthetic pathway is related to the polyisoprenoid biosynthetic pathway and that rubber transferase, which is the key enzyme in NR biosynthesis, belongs to the cis-prenyltransferase family. Here, we review recent progress in the elucidation of molecular mechanisms underlying NR biosynthesis through the identification of the enzymes that are responsible for the formation of the NR backbone structure.

Structural and Functional Annotation of Transposable Elements Revealed a Potential Regulation of Genes Involved in Rubber Biosynthesis by TE-Derived siRNA Interference in Hevea brasiliensis

“…Natural rubber biosynthetic pathway was very recently reviewed by [1]. Hevea brasiliensis is a sole tropical perennial crop used for the industrial production of natural rubber (NR) [2].…”

“…All genes involved in the NR biosynthesis pathway have been identified in the genomic sequences of the Chinese rubber clone Reyan 7-33-97 [4], and particularly the genes encoding the Rubber Elongation Factor (REF1-8) and Small Rubber Particle Protein (SRPP1-10) families. SRPPs were identified in many plants (rubber and non-rubber producing), while REFs were not found in other plants [1]. They have been shown to be more extended in Hevea compared to other rubber-producing plants [4,5], probably due to a whole genome duplication shared with cassava (Manihot esculenta), another Euphorbiaceae plant species [6].…”

Comparison of Morphological Characteristics and Determination of Different Patterns for Rubber Particles in Dandelion and Different Rubber Grass Varieties

“…Rubber particles are the main organelles of natural rubber biosynthesis (NRB) [ 30 ], and many crucial proteins involved in the NRB process have recently been identified from rubber particles by mass spectrometry [ 7 , 31 , 32 ]. These proteins include Cis-prenyltransferase (CPT), rubber elongation factor (REF), small rubber particle protein (SRPP), HRT1-REF bridging protein, a Nogo-B receptor (HRBP), isopentenyl pyrophosphate (IPP), etc.…”

“…Natural rubber (cis-1,4-polyisoprene) is widely used as an industrial and strategic raw material in nearly 50,000 products [ 7 , 8 ]. There are than more 12,500 latex-producing plants [ 9 ]; among them, approximately 2500 higher plant species can biosynthesize natural rubber [ 10 , 11 , 12 ], and these rubber-producing plants are distributed in at least eight families, indicating that natural rubber occurrence is polyphyletic in the plant kingdom [ 7 ]. However, until today, the Para rubber tree ( Hevea brasiliensis Muell.…”

“…In rubber-producing plants, a specific organelle, named the rubber particle, has been evolved to synthesize and store natural rubber in its laticifer cells [ 22 ]. It is a specialized spherical organelle that is surrounded by a lipid monolayer and membrane-bound proteins [ 7 ]. Morphological observation results demonstrated that the size of different rubber particles in various rubber-producing plants is different, and the number of rubber particles also varies among different plant species.…”