Development of Tissue-Specific Promoters for Plant Transformation

PABLO MANAVELLA; RAQUEL CHAN

Floriculture, Ornamental and Plant Biotechnology: advances and topical issues

Global Science Books

Lugar: Londres; Año: 2006; p. 21 - 25

Biotechnology contributes to the improvement of crops by introducing a single gene conferring a desired phenotype. To succeed in this process it is necessary to identify the gene able to confer the desired characteristic and a promoter region directing the expression of this gene in the adequate time and place. Each plant gene has its own promoter region, usually located upstream the coding sequences, presenting cis-acting elements responsible for tissue/organ specific expression as well as for induction/repression by external factors. Most recognition mechanisms are conserved in the whole plant kingdom, but significant differences have been observed between mono and dicot plants. Constitutive promoters are sequences that direct gene expression at a high level in the whole plant during all developmental stages. They have widely used for fundamental research as well as biotechnological tools, but their use leads to unnecessary metabolic expenses for the transformed plant. On the other hand, tissue/organ specific promoters have been described but expression directed by them is not enough strong to reach the desired acquired phenotype in the transformed plant. The use of artificial constructions combining specific cis-acting elements or entire weak promoters with enhancers is proposed. Several techniques developed to test a promoter?s activity are presented. Finally, we discuss the possibility to obtain improved ornamental plants in the future by a combination of a suitable promoter with a coding sequence able to confer a desired phenotype. Changing petals color or obtaining a senescence delay became possible objectives.