ABSTRACT
Observation of a differential expression pattern, including strong expression in meristematic tissue of an Agave tequilana GlsA/ZRF ortholog suggested an important role for this gene during bulbil formation and developmental changes in this species. In order to better understand this role, the two GlsA/ZFR orthologs present in the genome of Arabidopsis thaliana were functionally characterized by analyzing expression patterns, double mutant phenotypes, promoter-GUS fusions and expression of hormone related or meristem marker genes. Patterns of expression for A. thaliana show that GlsA/ZFR genes are strongly expressed in SAMs and RAMs in mature plants and developing embryos and double mutants showed multiple changes in morphology related to both SAM and RAM tissues. Typical double mutants showed stunted growth of aerial and root tissue, formation of multiple ectopic meristems and effects on cotyledons, leaves and flowers. The KNOX genes STM and BP were overexpressed in double mutants whereas CLV3, WUSCHEL and AS1 were repressed and lack of AtGlsA expression was also associated with changes in localization of auxin and cytokinin. These results suggest that GlsA/ZFR is an essential component of the machinery that maintains the integrity of SAM and RAM tissue and underline the potential to identify new genes or gene functions based on observations in non-model plants.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/physiology , Gene Expression Regulation, Plant/physiology , Genes, Plant/genetics , Meristem/physiology , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Genome, Plant , Mutagenesis, Insertional , Plants, Genetically ModifiedABSTRACT
Genetic variation in three forms of asexually propagated Agave tequilana Weber var. 'Azul' plants namely offsets, bulbils and in vitro cultured individuals was studied by AFLP analysis. Low levels of variation were observed between mother plants and offsets and a higher level between mother plant and bulbils. Families obtained from commercial plantations showed lower levels of variation in comparison to families grown as ornamentals. No variation was observed between the original explant and four generations of in vitro cultured plants. Epigenetic variation was also studied by analyzing changes in methylation patterns between mother plants and offspring in each form of asexual reproduction. Offsets and bulbils showed an overall decrease in methylation whereas in vitro cultured plants showed patterns specific to each generation: Generations 1 and 4 showed overall demethylation whereas Generations 2 and 3 showed increased methylation. Analysis of ESTs associated with transposable elements revealed higher proportions of ESTs from Ty1-copia-like, Gypsy and CACTA transposable elements in cDNA libraries obtained from pluripotent tissue suggesting a possible correlation between methylation patterns, expression of transposable element associated genes and somaclonal variation.
Subject(s)
Agave/genetics , DNA Methylation/genetics , DNA Transposable Elements/genetics , Polymorphism, Genetic/genetics , Reproduction, Asexual/genetics , Agave/growth & development , Amplified Fragment Length Polymorphism Analysis , Chromosome Mapping , DNA, Plant/chemistry , DNA, Plant/genetics , Gene Expression/genetics , Organogenesis/genetics , Phenotype , Plant Leaves/genetics , Plant Leaves/growth & development , TranscriptomeABSTRACT
La objeción de conciencia consiste en el incumplimiento de una obligación de naturaleza legal, cuya realización produciría en el individuo una grave lesión de la propia conciencia. Desde los mismos orígenes del Estado de Derecho, el respeto a la libertad de conciencia ha sido considerado uno de los derechos más fundamentales, ya que se presupone que la libertad y la dignidad humanas se encuentran por encima del mismo Estado.El derecho a la objeción de conciencia puede entenderse como la dimensión externa de la libertad ideológica y de conciencia. Este derecho, pilar esencial en todo Estado de Derecho, posee especial relevancia en el debate bioético, al tratarse de una vía muy adecuada para solucionar, en un sistema democrático, los inevitables conflictos que genera la tensión entre legalidad y justicia.En las últimas décadas, el derecho a la objeción de conciencia ha desarrollado toda su virtualidad en aquellos países en los que se han aprobado leyes despenalizadoras del aborto. Las profesiones sanitarias tienen un horizonte y un sentido claros: el cuidado y el respeto de la vida, la salud y la integridad de todos los seres humanos. En consecuencia, cuando una norma legal vulnera o contradice este principio, surgen sólidas razones para fundamentar el derecho a la objeción de conciencia de los sanitarios
