The expression of AtchitIV gene was analysed in Arabidopsis plants submitted to abiotic stresses. Transcript accumulation was detected in leaves in response to UV light exposure, exogenous salicylic acid administration and wounding. Transgenic Arabidopsis plants carrying AtchitIV promoter::gus fusion also showed differential expression of the reporter gene in response to these treatments. The AtchitIV expression was also analysed during Arabidopsis embryo development. GUS assay demonstrated AtchitIV promoter activation in zygotic embryos from torpedo stage up to full maturation. Promoter deletion analysis indicated that all the 5' cis-acting elements responsible for the specific tissue expression are located in a region of 1083 bp, adjacent to the start of transcription. A negative regulatory region located between portions -1083 and -600 was also observed.

O melhoramento vegetal vem sendo praticado pelo homem há milhares de anos. Entretanto, esse processo de domesticação tornou os vegetais mais susceptíveis a pragas e doenças. O melhoramento clássico permitiu, por cruzamento, a manipulação genética dos vegetais com conseqüente aumento na produtividade agrícola. Recentemente, a tecnologia do DNA recombinante ampliou as possibilidades de integração de genes exógenos ao genoma vegetal, resultando na produção das plantas transgênicas. Apesar das grandes discussões em torno do assunto, essas plantas representam hoje um caminho promissor para o melhoramento vegetal. Inúmeros exemplos de estratégias de transferência de genes conferiram, com sucesso, resistência a herbicidas, vírus, fungos, bactérias e insetos ou produziram um aumento na qualidade dos alimentos. Além das aplicações biotecnológicas, as plantas transgênicas têm contribuído significativamente para o estudo do funcionamento dos genes, tais como a análise da regulação da expressão gênica e o estudo das funções das proteínas codificadas pelos diferentes genes da planta.

Plant breeding has been a human practice for some thousands of years. However, this process of domestication has made plants more vulnerable to pests and diseases. Classical plant breeding has allowed the genetic manipulation of plants through crossings with a resulting increase in crop productivity. Recently, the recombinant DNA technology has increased the possibilities of integration of exogenous genes to the plant genome, resulting in the production of transgenic plants. Despite the great debate on this issue, such plants represent to date a promising avenue for plant breeding. There are many examples of gene transference strategies which have been successful in promoting resistance to herbicides, viruses, fungi, bacteria and insects, or in producing an increase in food quality. In addition to biotechnological applications, transgenic plants have made a significant contribution to the study of gene functioning, such as the analysis of genic expression regulation and the study of protein functions codified by distinct plant genes.