Drought tolerance is an important character for agricultural crops, particularly corn. Genes confering this feature can be patented, thus hindering their use. From a thorough analysis, three genes (DREB, ZAT10 and CspB) were identified and their sequences were captured in the NCBI database. From these sequences and using free software tools, expression cassettes -including regulatory regions (promoters E35S + Pleader, Ubi-1, rab17; terminators Trub, Tnos)- were designed. Patent searches were conducted in international databases (The Lens and PATENTSCOPE). Four patents and an application were found. In the Colombian national database of the Superintendence of Industry and Commerce (SIC), only the application made through PCT was identified. The claims and nucleotide sequences contained in the application were analyzed and it was found that they do not affect the expression cassettes designed. There is freedom to operate for these constructs and it is possible to continue developing drought-tolerant GM maize lines for the domestic market.

RESUMENComo primera aproximación en la obtención de una línea transgénica de maíz tolerante a sequía y al herbicida glufosinato de amonio, se seleccionaron genes y elementos reguladores para el diseño in silico de casetes de expresión, a través del análisis de literatura científica y bases de datos de genes y patentes. Las secuencias génicas fueron modificadas con base en el criterio de uso codónico del maíz para optimizar su expresión. Los casetes de expresión diseñados con el software DNA 2.0., fueron sintetizados por una empresa especializada. La presencia del transgen y la expresión a nivel de mARN fue demostrada mediante PCR y RT-PCR en la planta modelo Nicotiana benthamiana transformada vía Agrobacterium tumefaciens. Un ensayo preliminar in vitro en condiciones simuladas de sequía en medio MS con PEG (PM 6000)10 % no demostró incremento notorio en la tolerancia de las plántulas transformantes, posiblemente debido a que el uso codónico del diseño no favorece la expresión génica en la planta modelo.Palabras clave: estrés abiótico, tolerancia a herbicida, transgénesis, uso codónico. ABSTRACTAs a first approach in obtaining a transgenic drought and glufosinate ammonium tolerant maize line, genes and regulatory elements for the in silico design of the expression cassettes were selected through analysis of scientific literature and databases of genes and patents. Gene sequences were modified based on the criterion of maize codon usage to optimize their expression. The constructs designed with DNA 2.0 Software, were synthesized by a specialized company. The presence of the transgene and the expression of mRNA was demonstrated by PCR and RT-PCR in the model plant Nicotiana benthamiana transformed via Agrobacterium tumefaciens. A preliminary experiment in vitro under simulated drought conditions in MS medium with 10 % PEG (PM 6000) showed no noticeable increase in drought tolerance of the transformants, possibly because the codon usage of the design does not promote gene expression in the model plant.