Caracterização de genes de Arabidopsis thaliana e Saccharum spp envolvidos na resposta ao frio e oxido nitrico

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Nitric oxide (NO) is a reactive nitrogen species relatively unstable that has great versatility. NO acts as a secondary messenger and may be even cytotoxic, depending on its concentration. Actions of the NO as secondary messenger have been described in neurotransmission, regulation of the blood circulation and inflammatory processes mainly in mammals where the enzyme NO-synthase (NOS) was discovered. In plants, NO has important role in plant-pathogen interactions, in foliar expansion and in the maturation and sencescence of fruits and flowers. Recently two NO isoforms have been characterized in Arabidopsis thaliana, but we are far from a complete understanding of the NO effects on gene expression. This work reports the cloning and characterization of a NOS isoform from A. thaliana and the modulation of gene expression in sugarcane by NO donors. Gene-specific oligonucleotides were designed based on the sequence of an animal NO-synthase deposited in the NCBI. After reverse-transcription and PCR the open reading frame was cloned and the gene was named HHP. The highest levels of gene expression were observed in leaves and flowers. HHP was induced by cold stress. The subcelular localization of the protein, determined using a GFP fusion, was predominantly plastidic. Transgenic A. thaliana superexpressing the HHP gene were more tolerant to cold stress. The effect of NO on sugarcane cells was evaluated using DNA macroarrays. Several genes were found to be modulated by NO, such as those encoding an aminotransferase and a peroxidase. Surprisingly, most of them encode proteins with unknown function. The influence of plastics used to seal macroarray membranes was also evaluated. It was found that some of them block the radiation transmittance, reducing the number of detected spots and consequently the number of genes evaluated in the assay. These findings indicate that the choice of the sealing plastic is very important to obtain the maximum information from nylon arrays.

ASSUNTO(S)

oxido nitrico genes cana-de-açucar

ACESSO AO ARTIGO

Documentos Relacionados