title: Molecular characterization and expression analysis of cDNAs encoding four Rab and two Arf GTPases in the latex of Hevea brasiliensis.
abstract: In plants, Rab and Arf GTPases are key regulators of vesicle trafficking. To investigate whether these small GTPases (SG) play a role in the regulation of the regeneration of latex (the cytoplasm of the rubber-producing laticifer cell) in Hevea brasiliensis (Hevea hereafter), full-length cDNAs that encode four HbRab and two HbArf GTPases were cloned. The four HbRab proteins showed specific GTP-binding activity when expressed in Escherichia coli. Transcript expression of the six SG genes was investigated by real-time RT-PCR. All genes revealed to be expressed in each of the six Hevea tissues examined, but the expression patterns were different. Four genes, HbArf1, HbRab2, HbRab3 and HbRab4, displayed a preferential expression in latex. The expression of all genes was upregulated by the act of latex exploitation (tapping), and HbRab1 had the highest level of upregulation. Wounding markedly upregulated the expression of two SG genes (HbRab1 and HbArf2), and exogenous methyl jasmonate upregulated all six SG genes. Wounding might upregulate the expression of HbRab1 and HbArf2 through a jasmonic acid-mediated signaling pathway. None of the genes were markedly upregulated by Ethrel (an ethylene releaser and latex stimulator); instead, HbArf2 and HbRab4 were downregulated significantly after a 24 h treatment with Ethrel. This paper gives the first description of Rab and Arf GTPases in Hevea and provides clues for their involvement, HbRab1 in particular, in latex regeneration.
authors.affiliation: Key Lab of Rubber Biology, Ministry of Agriculture & Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan 571737, China.
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Qin
authors.forename: Feng
authors.initials: F
authors.lastname: Shi
authors.forename: Chaorong
authors.initials: C
authors.lastname: Tang
mesh_terms: D020727:ADP-Ribosylation Factors / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D000085:Acetates / Q000494:pharmacology; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D016384:Consensus Sequence; D003517:Cyclopentanes / Q000494:pharmacology; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D035264:Flowers / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D028482:Hevea / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D007840:Latex / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D009943:Organophosphorus Compounds / Q000494:pharmacology; D054883:Oxylipins / Q000494:pharmacology; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D010940:Plant Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018547:Plant Stems / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D017434:Protein Structure, Tertiary; D018749:RNA, Plant / Q000235:genetics; D012639:Seeds / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020691:rab GTP-Binding Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D018076:DNA, Complementary; D007840:Latex; D009943:Organophosphorus Compounds; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D018749:RNA, Plant; C072239:methyl jasmonate; D020727:ADP-Ribosylation Factors; D020691:rab GTP-Binding Proteins; C005073:ethephon