title: Metabolic routes affecting rubber biosynthesis in Hevea brasiliensis latex.
abstract: The cytosolic mevalonate (MVA) pathway in Hevea brasiliensis latex is the conventionally accepted pathway which provides isopentenyl diphosphate (IPP) for cis-polyisoprene (rubber) biosynthesis. However, the plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway may be an alternative source of IPP since its more recent discovery in plants. Quantitative RT-PCR (qRT-PCR) expression profiles of genes from both pathways in latex showed that subcellular compartmentalization of IPP for cis-polyisoprene synthesis is related to the degree of plastidic carotenoid synthesis. From this, the occurrence of two schemes of IPP partitioning and utilization within one species is proposed whereby the supply of IPP for cis-polyisoprene from the MEP pathway is related to carotenoid production in latex. Subsequently, a set of latex unique gene transcripts was sequenced and assembled and they were then mapped to IPP-requiring pathways. Up to eight such pathways, including cis-polyisoprene biosynthesis, were identified. Our findings on pre- and post-IPP metabolic routes form an important aspect of a pathway knowledge-driven approach to enhancing cis-polyisoprene biosynthesis in transgenic rubber trees.
authors.affiliation: Malaysian Rubber Board, Rubber Research Institute of Malaysia, Experiment Station, Selangor, Malaysia. kschow@lgm.gov.my
authors.forename: Keng-See
authors.initials: KS
authors.lastname: Chow
authors.forename: Mohd-Noor
authors.initials: MN
authors.lastname: Mat-Isa
authors.forename: Azlina
authors.initials: A
authors.lastname: Bahari
authors.forename: Ahmad-Kamal
authors.initials: AK
authors.lastname: Ghazali
authors.forename: Halimah
authors.initials: H
authors.lastname: Alias
authors.forename: Zainorlina
authors.initials: Z
authors.lastname: Mohd-Zainuddin
authors.forename: Chee-Choong
authors.initials: CC
authors.lastname: Hoh
authors.forename: Kiew-Lian
authors.initials: KL
authors.lastname: Wan
mesh_terms: D001483:Base Sequence; D002338:Carotenoids / Q000378:metabolism; D004896:Erythritol / Q000031:analogs & derivatives* / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics*; D015723:Gene Library; D017343:Genes, Plant / Q000235:genetics; D028482:Hevea / Q000235:genetics / Q000378:metabolism*; D007840:Latex / Q000032:analysis*; D008798:Mevalonic Acid / Q000378:metabolism*; D008969:Molecular Sequence Data; D018749:RNA, Plant / Q000235:genetics; D012408:Rubber / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D013403:Sugar Phosphates / Q000378:metabolism*; D013729:Terpenes / Q000378:metabolism; D059467:Transcriptome
chemical_list: C114232:2-C-methylerythritol 4-phosphate; D007840:Latex; D018749:RNA, Plant; D013403:Sugar Phosphates; D013729:Terpenes; D002338:Carotenoids; D012408:Rubber; D004896:Erythritol; D008798:Mevalonic Acid