Análise da expressão gênica induzida por Diatraea saccharalis em cana-de-açúcar via macroarranjos de colônias bacterianas. / Analysis of expressed genes induced by Diatraea saccharalis in sugarcane using bacterial colonies arrays.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Large-scale sequencing and the application of expressed sequence tag (EST) technology has led to the identification of hundreds of thousands of genomic sequences from various organisms. Through projects like the Sugarcane Expressed Sequence Tag (SUCEST), DNA arrays technology could be applied in monitoring gene expression. The first step of this work was to optimize the macroarray technique with bacterial colonies. Arrays were robotically constructed (Q-Bot). Bacterial cells carrying sugarcane cDNA clones were arrayed in duplicate onto nylon membrane and grown for 6 and 12 hours. As a result, we conclude that is possible to study the gene expression in large-scale using macroarray through bacterial colony that grown for 6 hours. The second part of this work was to study how different two sugarcane varieties (Saccharum sp.) are in response resistance against Diatraea saccharalis (Lepidoptera: Crambidae). Sugarcane is of great importance for Brazilian’s agriculture and for the general economy of many tropical developing countries. These plants are attacked by D. saccharalis, the most important insect pest of sugarcane, causing significant economic losses. As it is well known, plants have evolved complex defense strategies to protect them in opposition to attack by insects. The varieties SP80-3280 (susceptible) and SP81-3250 (tolerant) were exposed to D. saccharalis. Plants materials from plants with the borer and control plants (without the borer) were collected at 0.5, 6, 12 and 24 hours time points. The analysis revealed genes differentially expressed in response to sugarcane borer in both varieties. We analyzed the timing, dynamics, and regulation of the expression of 3,840 SUCEST clones, which were grown on a nylon membrane for 6 h. These ESTs was grouped into 16 broad categories: amino-acid metabolism, plant grow and development, protein metabolism, RNA metabolism, secondary metabolism, stress response, transport, bioenergetics, signal transduction, cellular dynamics, DNA metabolism, lipid, fatty-acid metabolism, mobile genetic elements, nitrogen, sulphur and phosphate metabolism, nucleotide metabolism, and the group matched to unable to classify, which no indication of the function of the gene product are known. These results help to elucidate the defense strategies developed by sugarcane in order to prevent against insect damage. In this study, macroarray analyses revealed 580 ESTs with increased expression, from both varieties. These results are important not only because this is the first large-scale gene expression study of a monocot in response to insect attack, but also because it allows the comparison of the gene expression pattern between susceptible and tolerant genotypes. This study opens possibilities for genetically-engineering of insect-resistant sugarcane and for using these genes as molecular markers in conventional breeding programs.

ASSUNTO(S)

plant resistance brocas (insetos nocivos) resistência genética vegetal sugarcane cana-de-açúcar gene expression sugarcane borer expressão gênica

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