Ethylene stimulation of latex production in Hevea brasiliensis

T1 - Metabolic routes affecting rubber biosynthesis in Hevea brasiliensis latex
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and methionine form thiols in the latex of Hevea brasiliensis .

The team looked for genes related to rubber itself and for resisting disease — two factors that affect rubber production. They found that the two most abundant proteins that make up rubber — Rubber Elongation Factor and Small Rubber Particle — are encoded on a large number of genes that are clustered together in a small region of the genome. While other tropical plants also express these proteins to some extent, being encoded more than eight times on different genes is unique to H. brasiliensis Cap analysis gene expression (CAGE) — a method developed at RIKEN — revealed that expression of these proteins is tissue specific, with expression more than 100 times greater in latex than in leaves.

T1 - Insights into rubber biosynthesis from transcriptome analysis of Hevea brasiliensis latex
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Publications - Official Portal of Malaysian Rubber Board

Natural rubber (-1,4-polyisoprene) ,which is a secondary metabolite of , is a strategic raw material. However, only little is known about the mechanism of rubber biosynthesis.
Small rubber particle protein (SRPP) and rubber elongation factor (REF) are two major proteins found in latex and are considered to participate in rubber biosynthesis.
In this study, we analyzed the localization of these proteins by employing immuno-histochemical methods with using anti-SRPP and anti-REF antibodies. The results indicated that SRPP and REF were specifically expressed in laticifers, furthermore, both of these proteins were localized on rubber particles. Interestingly, qualitative difference of rubber particle was also suggested in terms of the distribution of these proteins.

3-Hydroxy-3-Methylgl utaryl-CoA Reductase and Rubber Biosynthesis of Hevea brasiliensis ..
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AB - Hevea brasiliensis is the most widely cultivated species for commercial production of natural rubber (cis-polyisoprene). In this study, 10 040 expressed sequence tags (ESTs) were generated from the latex of the rubber tree, which represents the cytoplasmic content of a single cell type, in order to analyse the latex transcription profile with emphasis on rubber biosynthesis-related genes. A total of 3441 unique transcripts (UTs) were obtained after quality editing and assembly of EST sequences. Functional classification of UTs according to the Gene Ontology convention showed that 73.8% were related to genes of unknown function. Among highly expressed ESTs, a significant proportion encoded proteins related to rubber biosynthesis and stress or defence responses. Sequences encoding rubber particle membrane proteins (RPMPs) belonging to three protein families accounted for 12% of the ESTs. Characterization of these ESTs revealed nine RPMP variants (7.9-27 kDa) including the 14 kDa REF (rubber elongation factor) and 22 kDa SRPP (small rubber particle protein). The expression of multiple RPMP isoforms in latex was shown using antibodies against REF and SRPP. Both EST and quantitative reverse transcription-PCR (QRT-PCR) analyses demonstrated REF and SRPP to be the most abundant transcripts in latex. Besides rubber biosynthesis, comparative sequence analysis showed that the RPMPs are highly similar to sequences in the plant kingdom having stress-related functions. Implications of the RPMP function in cis-polyisoprene biosynthesis in the context of transcript abundance and differential gene expression are discussed.

Localization Analysis of the Rubber Biosynthetic Protein in Hevea brasiliensis ..
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Metabolic routes affecting rubber biosynthesis in ..

N2 - Hevea brasiliensis is the most widely cultivated species for commercial production of natural rubber (cis-polyisoprene). In this study, 10 040 expressed sequence tags (ESTs) were generated from the latex of the rubber tree, which represents the cytoplasmic content of a single cell type, in order to analyse the latex transcription profile with emphasis on rubber biosynthesis-related genes. A total of 3441 unique transcripts (UTs) were obtained after quality editing and assembly of EST sequences. Functional classification of UTs according to the Gene Ontology convention showed that 73.8% were related to genes of unknown function. Among highly expressed ESTs, a significant proportion encoded proteins related to rubber biosynthesis and stress or defence responses. Sequences encoding rubber particle membrane proteins (RPMPs) belonging to three protein families accounted for 12% of the ESTs. Characterization of these ESTs revealed nine RPMP variants (7.9-27 kDa) including the 14 kDa REF (rubber elongation factor) and 22 kDa SRPP (small rubber particle protein). The expression of multiple RPMP isoforms in latex was shown using antibodies against REF and SRPP. Both EST and quantitative reverse transcription-PCR (QRT-PCR) analyses demonstrated REF and SRPP to be the most abundant transcripts in latex. Besides rubber biosynthesis, comparative sequence analysis showed that the RPMPs are highly similar to sequences in the plant kingdom having stress-related functions. Implications of the RPMP function in cis-polyisoprene biosynthesis in the context of transcript abundance and differential gene expression are discussed.

The biosynthesis of rubber from β-hydroxy-β …

Researchers from RIKEN Center for Sustainable Resource Science (CSRS) in Japan and collaborators from UniversitiSains Malaysia (USM) have successfully decoded the genome sequence for Hevea brasiliensis, the natural rubber tree native to Brazil. The study, published in Scientific Reports, shows a draft genome sequence that covers more than 93% of expressed genes and pinpoints regions specific to the biosynthesis of rubber.

Rubber Elongation Factor (REF), a Major Allergen …

Hevea brasiliensis is the most widely cultivated species for commercial production of natural rubber (cis-polyisoprene). In this study, 10 040 expressed sequence tags (ESTs) were generated from the latex of the rubber tree, which represents the cytoplasmic content of a single cell type, in order to analyse the latex transcription profile with emphasis on rubber biosynthesis-related genes. A total of 3441 unique transcripts (UTs) were obtained after quality editing and assembly of EST sequences. Functional classification of UTs according to the Gene Ontology convention showed that 73.8% were related to genes of unknown function. Among highly expressed ESTs, a significant proportion encoded proteins related to rubber biosynthesis and stress or defence responses. Sequences encoding rubber particle membrane proteins (RPMPs) belonging to three protein families accounted for 12% of the ESTs. Characterization of these ESTs revealed nine RPMP variants (7.9-27 kDa) including the 14 kDa REF (rubber elongation factor) and 22 kDa SRPP (small rubber particle protein). The expression of multiple RPMP isoforms in latex was shown using antibodies against REF and SRPP. Both EST and quantitative reverse transcription-PCR (QRT-PCR) analyses demonstrated REF and SRPP to be the most abundant transcripts in latex. Besides rubber biosynthesis, comparative sequence analysis showed that the RPMPs are highly similar to sequences in the plant kingdom having stress-related functions. Implications of the RPMP function in cis-polyisoprene biosynthesis in the context of transcript abundance and differential gene expression are discussed.