Caracterização e utilização de genes envolvidos na tolerancia ao aluminio toxico em milhodissertation
Аннотация: Characterization and utilization of genes involved with aluminum tolerance in maizeAcid soils are found worldwide but most of them are located in tropical and subtropical regions.Aluminum (Al), the most abundant metal on the earth surface, becomes soluble in the soil solution as consequence of low pH in acid soils and achieves phytotoxic levels for most of the cultivated plant species.The first symptom of Al toxicity is the inhibition of the root growth that promote physiological disturbs reducing crop yield.Because of limitations of correcting soil pH by liming and the time-consuming process of traditional plant breeding, the elucidation of the mechanisms involved with plant Al-tolerance and Al-toxicity has received more attention, since the production of genetically altered plants has emerged as an effective and fast strategy to the production of improved cultivars.Two maize lines, Cat100-6 (Al-tolerant) and S1587-17 (Al-sensitive), were used in this study with the aim of understanding at the transcriptional level the alterations promoted by Al on the roots.The research was divided in three main sections: i) detection, cloning and characterization of a gene encoding a Glutathione S-transferase in maize and evaluation of Al effects on its expression; ii) Large-scale evaluation of gene expression in root tips of maize under Al stress using a heterologous system with Expressed Sequence Tags (ESTs) of sugarcane; and iii) cloning and characterization of the ALMT1 gene in maize and evaluation of Al-effects on its activity.In the first section was observed that Al and Cd-stress induced the GST27.2gene.Two mutations present on the nucleotide chain of this gene promoted alteration on the amino acid compositions.These alterations might be responsible by alterations on the specificity and activity of the GST enzyme.Besides that, the GST27.2 is a single copy gene in maize and seem to be a new allele of GST27.In the section of large-scale gene expression evaluation were identified 85 genes in root tips of two Al-tolerant contrasting maize lines whose expression was altered by Al
Год издания: 2006
Ключевые слова: Aluminum toxicity and tolerance in plants and animals, Silicon Effects in Agriculture, Plant Micronutrient Interactions and Effects
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