RESUMO
A cDNA (CitPAP) homologous to a gene encoding for Cucumis sativus carotenoid-associated protein (CHRC) has been isolated from satsuma mandarin (Citrus unshiu Marc.). Unlike ChrC whose expression was limited only in mature fruits (containing chromoplasts), CitPAP transcripts were detected in all the tissues examined including fruits, flowers and leaves. In this respect, CitPAP was rather close to a gene encoding for pepper plastid-lipid-associated protein (PAP), which exhibits ubiquitous expression in bell pepper organs containing chloroplasts or chromoplasts. CitPAP, however, differed from PAP in the magnitude and pattern of RNA accumulation. These results might indicate a novel function of CitPAP.
Assuntos
Proteínas de Transporte/genética , Citrus/genética , Sequência de Aminoácidos , Sequência de Bases , Proteínas de Transporte/biossíntese , Proteínas de Transporte/química , DNA Complementar , Dados de Sequência Molecular , Folhas de Planta , Proteínas de Plantas/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
A cDNA homologue to the human defender against apoptotic death gene (dad-1), which is involved in programmed cell death, was isolated from satsuma mandarin (Citrus unshiu Marc.) fruit. It (Citdad-1-1) was 345 bp long, with a deduced protein sequence of 115 amino acids. Southern hybridization suggests that dad-1-related sequences are present as a small gene family in the citrus genome. Expression of Citdad-1-1 was progressively down-regulated in leaves as they matured, but not in juice sac/segment epidermis (edible part) towards fruit ripening. The role of dad-1 during citrus development is also discussed.
Assuntos
Citrus/genética , Genes de Plantas , Sequência de Aminoácidos , Citrus/crescimento & desenvolvimento , Clonagem Molecular , Biblioteca Gênica , Dados de Sequência Molecular , Alinhamento de SequênciaRESUMO
We carried out a random sequencing of cDNA library derived from mature citrus fruit (Citrus unshiu Marc.) for identifying the gene repertoires expressed at the mature stage. Among 297 clones analyzed, 195 cDNA clones (65.7%) were putatively identified to previously characterized genes with optimized (OPT) scores of >/=200 through a homology search to DNA database, whereas 102 clones (34.3%) resulted in low OPT scores (<200) and did not show any significant sequence identity with previously published genes. Among them, clones homologous to metallothionein (MT)-like genes appeared 62 times, being mostly redundant, and accounting for about 20.9% of the total 297 clones. To gain a better understanding of the MT-like genes, two types of cDNA clones were isolated. One clone (CitMT36) resembled the type 2 MT gene containing Cys-X-Cys motifs in both N- and C-terminal, but the consensus sequence in the N-terminal domain, Cys-Cys and Cys-X-X-Cys was modified in CitMT36 to X-Cys and Cys-X-X-X, respectively. We suggest that these form a 'novel type 2' group of MT-like clones. The other clone (CitMT45) showed homology to type 3 MT-like genes, which have been found in mostly fruit tissues so far. By Southern blot analysis, both clones showed one or two bands, suggesting that both CitMT36 and CitMT45 are present in single or a few copies in the citrus genome. Transcripts of CitMT36 were evenly detected in all tissues examined, whereas those of CitMT45 were detected primarily in fruit during the developmental phase. Neither of the MT-like genes was induced in leaves by Zn and Cu. Collectively, MT-like genes from citrus would be regulated differentially depending on the fruit developmental stage and organs, indicating a change in their expression under the different physiological and molecular environment of fruit cells.
Assuntos
Citrus/crescimento & desenvolvimento , Citrus/genética , Biblioteca Gênica , Genes de Plantas/genética , Metalotioneína/genética , Sequência de Aminoácidos , Northern Blotting , Southern Blotting , Citrus/química , DNA Complementar/genética , DNA Complementar/isolamento & purificação , DNA de Plantas/química , DNA de Plantas/genética , Dosagem de Genes , Expressão Gênica/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes/genética , Genoma , Dados de Sequência Molecular , RNA de Plantas/análise , Técnica de Amplificação ao Acaso de DNA Polimórfico , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência de AminoácidosRESUMO
We isolated a cDNA clone encoding limonoid UDP-glucosyltransferase (limonoid GTase) from the albedo of Satsuma mandarin (Citrus unshiu Marc.) and investigated the contribution to limonoid glucoside accumulation in fruit. The isolated cDNA clone (CitLGT) was 1732 bp in length encoding 511 deduced amino acids with a predicted molecular mass of 57.5 kDa. The products of in vitro translation from an expression vector had the limonoid GTase activity. Southern blot analysis of genomic DNA indicated that CitLGT was present as a single copy gene in the Citrus genome. The amount of transcript corresponding to CitLGT mRNA changed the same way as the fluctuation of limonin glucoside content during fruit development of navel orange (Citrus sinensis Osb.). This indicates that the transcription of CitLGT regulates the conversion of limonoid aglycones to glucosides in citrus fruit.
Assuntos
Citrus/química , Glucosiltransferases/genética , Glucosiltransferases/isolamento & purificação , Limoninas , Triterpenos/isolamento & purificação , Triterpenos/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Northern Blotting , Southern Blotting , Citrus/enzimologia , Citrus/metabolismo , Clonagem Molecular , Glucosiltransferases/química , Glucosiltransferases/metabolismo , Dados de Sequência Molecular , RNA de Plantas/análise , Alinhamento de Sequência , Análise de Sequência de Proteína , Triterpenos/químicaRESUMO
Changes in mRNA levels for the seven gene homologues to endoxyloglucan transferase-related protein, expansin, extensin, ß-1,3 glucanase, glycine-rich protein, pectinacetylesterase and pectinesterase, which were obtained by random sequencing studies, were investigated in relation to rind development in citrus (Citrus unshiu Marc.) fruit. Expression patterns in the albedo and flavedo were classified into four types: Type-I, transcript levels low in early fruit development but increased at the ripening stage; Type-II, transcript levels high until mid-development and then decreased towards ripening; Type-III, detectable transcript limited to fruitlets at 26 days after flowering (DAF); Type-IV, ubiquitous during the development. Based on the expression patterns, we discuss the possible roles of these genes in rind development.