RESUMEN
Vascular plants appeared ~410 million years ago, then diverged into several lineages of which only two survive: the euphyllophytes (ferns and seed plants) and the lycophytes. We report here the genome sequence of the lycophyte Selaginella moellendorffii (Selaginella), the first nonseed vascular plant genome reported. By comparing gene content in evolutionarily diverse taxa, we found that the transition from a gametophyte- to a sporophyte-dominated life cycle required far fewer new genes than the transition from a nonseed vascular to a flowering plant, whereas secondary metabolic genes expanded extensively and in parallel in the lycophyte and angiosperm lineages. Selaginella differs in posttranscriptional gene regulation, including small RNA regulation of repetitive elements, an absence of the trans-acting small interfering RNA pathway, and extensive RNA editing of organellar genes.
Asunto(s)
Evolución Biológica , Genoma de Planta , Selaginellaceae/genética , Bryopsida/genética , Chlamydomonas/química , Chlamydomonas/genética , Elementos Transponibles de ADN , Evolución Molecular , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Magnoliopsida/química , Magnoliopsida/genética , MicroARNs/genética , Datos de Secuencia Molecular , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteoma/análisis , Edición de ARN , ARN de Planta/genética , Secuencias Repetitivas de Ácidos Nucleicos , Selaginellaceae/crecimiento & desarrollo , Selaginellaceae/metabolismo , Análisis de Secuencia de ADNRESUMEN
The putative alpha-galactosidase gene HvSF11 of barley, previously shown to be expressed during dark induced senescence, is expressed in the growing/elongating zone of primary foliage leaves of barley. The amino acid sequence deduced from the full length HvSF11 cDNA contains a hydrophobic signal sequence at the N-terminus. Phylogenetic relationship of the HvSF11 encoded barley alpha-galactosidase to other alpha-galactosidases revealed high homology with the alpha-galactosidase encoded by the gene At5g08370 from Arabidopsis thaliana. We have isolated two independent heterozygous At5g08370 T-DNA insertion mutants from Arabidopsis thaliana, both of which have a higher number of rosette leaves with a curly surface leaf morphology and delayed flowering time in comparison to wildtype plants. Localization of the Arabidopsis alpha-galactosidase protein via GUS-tag revealed that the protein is associated with the cell wall. This result was confirmed by immunological detection of the orthologous barley protein in a protein fraction derived from cell walls of barley leaves. It is concluded that the alpha-galactosidase proteins from barley and Arabidopsis might fulfill an important role in leaf development by functioning in cell wall loosening and cell wall expansion.
