RESUMEN
BACKGROUND AND AIMS: Bananas and plantains (Musa spp.) are one of the major fruit crops worldwide with acknowledged importance as a staple food for millions of people. The rich genetic diversity of this crop is, however, endangered by diseases, adverse environmental conditions and changed farming practices, and the need for its characterization and preservation is urgent. With the aim of providing a simple and robust approach for molecular characterization of Musa species, we developed an optimized genotyping platform using 19 published simple sequence repeat markers. METHODOLOGY: The genotyping system is based on 19 microsatellite loci, which are scored using fluorescently labelled primers and high-throughput capillary electrophoresis separation with high resolution. This genotyping platform was tested and optimized on a set of 70 diploid and 38 triploid banana accessions. PRINCIPAL RESULTS: The marker set used in this study provided enough polymorphism to discriminate between individual species, subspecies and subgroups of all accessions of Musa. Likewise, the capability of identifying duplicate samples was confirmed. Based on the results of a blind test, the genotyping system was confirmed to be suitable for characterization of unknown accessions. CONCLUSIONS: Here we report on the first complex and standardized platform for molecular characterization of Musa germplasm that is ready to use for the wider Musa research and breeding community. We believe that this genotyping system offers a versatile tool that can accommodate all possible requirements for characterizing Musa diversity, and is economical for samples ranging from one to many accessions.
RESUMEN
The transition from the juvenile to the mature phase during vegetative development in plants is characterized by changes in leaf shape. We show that GENERAL TRANSCRIPTION FACTOR GROUP E6 (GTE6) regulates differences in leaf patterning between juvenile and mature leaves in Arabidopsis. GTE6 encodes a novel small bromodomain-containing protein unique to plants. Mutations in GTE6 disrupt the formation of elliptical leaf laminae in mature leaves, whereas overexpression of GTE6 resulted in elongated juvenile leaves. GTE6 positively regulates the expression of ASYMMETRIC LEAVES1 (AS1), which encodes a myb-domain protein that controls proximodistal patterning of leaves. Using chromatin immunoprecipitation (ChIP) assays, we show that GTE6 is associated with the promoter and the start of the transcribed region of AS1 and up-regulates expression of AS1 through acetylation of histones H3 and H4. Genetic studies demonstrated that AS1 is epistatic to GTE6, indicating that GTE6 regulates AS1 during leaf morphogenesis. Chromatin remodeling at AS1 is a key regulatory mechanism in leaf development, which ensures the continual production of mature leaves following juvenile-adult transition, thereby maintaining the identity of the mature vegetative phase.
Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Histonas/metabolismo , Hojas de la Planta/crecimiento & desarrollo , Factores de Transcripción/genética , Acetilación , Arabidopsis/crecimiento & desarrollo , Proteínas de Arabidopsis/metabolismo , Inmunoprecipitación de Cromatina , Epistasis Genética , Genes de Plantas , Proteínas Fluorescentes Verdes/metabolismo , Histonas/genética , Proteínas de Homeodominio/metabolismo , Microscopía Confocal , Mutagénesis Insercional , Mutación , Regiones Promotoras Genéticas , Proteínas Recombinantes de Fusión/metabolismo , Factores de Transcripción/metabolismoRESUMEN
In Chinese rose species and in many modern varieties, two methylated phenolic derivatives, 3,5-dimethoxytoluene and 1,3,5-trimethoxybenzene, are major scent components. We show that cell-free extracts of rose petals catalyse the synthesis of 3,5-dimethoxytoluene and 1,3,5-trimethoxybenzene by methylation of precursor molecules. An expressed sequence tag approach was used to identify four highly similar O-methyltransferase sequences expressed specifically in petals and anthers. Thin layer chromatography analysis showed that the activities of these enzymes with different substrates and the proportions of reaction products produced closely mimicked those observed using cell-free petal extracts, indicating that orcinol O-methyltransferases are responsible for the biosynthesis of 3,5-dimethoxytoluene and 1,3,5-trimethoxybenzene from un-methylated precursors in this organ.
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Anisoles/metabolismo , Metiltransferasas/metabolismo , Floroglucinol/análogos & derivados , Floroglucinol/metabolismo , Resorcinoles/metabolismo , Rosa/enzimología , Clonación Molecular , Metilación , Metiltransferasas/genética , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Especificidad por SustratoRESUMEN
Single-pass sequences were obtained from the 5'-ends of a total of 1794 rose petal cDNA clones. Cluster analysis identified 242 groups of sequences and 635 singletons indicating that the database represents a total of 877 genes. Putative functions could be assigned to 1151 of the transcripts. Expression analysis indicated that transcripts of several of the genes identified accumulated specifically in petals and stamens. The cDNA library and expressed sequence tag database described here represent a valuable resource for future research aimed at improving economically important rose characteristics such as flower form, longevity and scent.