RESUMEN
The polyenoic fatty acid isomerase from Propioniumbacterium acnes (PAI) was expressed in E. coli and biochemically characterized. PAI catalyzes the isomerization of a methylene-interrupted double bond system to a conjugated double bond system, creating (10E,12Z)-conjugated linoleic acid (CLA). PAI accepted a wide range of free polyunsaturated fatty acids as substrates ranging from 18:2 fatty acids to 22:6, converting them to fatty acids with two or three conjugated double bonds. For expression of PAI in yeast the PAI-sequence encoding 20 N-terminal amino acid residues was altered for optimal codon usage, yielding codon optimized PAI (coPAI). The percentage of 10,12-CLA of total esterified fatty acids was 8 times higher in yeast transformed with coPAI than in cells transformed with PAI. CLA was detected in amounts up to 5.7% of total free fatty acids in yeast transformed with coPAI but none was detected in yeast transformed with PAI. PAI or coPAI under the control of the constitutive CaMV 35S promoter or the seed-specific USP promoter was transformed into tobacco plants. CLA was only detected in seeds in coPAI-transgenic plants. The amount of CLA detected in esterified fatty acids was up to 0.3%, in free fatty acids up to 15%.
Asunto(s)
Isomerasas de Doble Vínculo Carbono-Carbono/metabolismo , Ácidos Linoleicos Conjugados/biosíntesis , Nicotiana/metabolismo , Saccharomyces cerevisiae/metabolismo , Semillas/metabolismo , Actinomycetales/enzimología , Actinomycetales/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Secuencia de Bases , Biotecnología/métodos , Isomerasas de Doble Vínculo Carbono-Carbono/genética , Codón , Concentración de Iones de Hidrógeno , Ácidos Linoleicos Conjugados/metabolismo , Datos de Secuencia Molecular , Regiones Promotoras Genéticas , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/genética , Semillas/genética , Especificidad por Sustrato , Nicotiana/genéticaRESUMEN
As global populations continue to increase, agricultural productivity will be challenged to keep pace without overtaxing important environmental resources. A dynamic and integrated approach will be required to solve global food insecurity and position agriculture on a trajectory toward sustainability. Genetically modified (GM) crops enhanced through modern biotechnology represent an important set of tools that can promote sustainable agriculture and improve food security. Several emerging biotechnology approaches were discussed in a recent symposium organized at the 13th IUPAC International Congress of Pesticide Chemistry meeting in San Francisco, CA, USA. This paper summarizes the innovative research and several of the new and emerging technologies within the field of agricultural biotechnology that were presented during the symposium. This discussion highlights how agricultural biotechnology fits within the context of sustainable agriculture and improved food security and can be used in support of further development and adoption of beneficial GM crops.
Asunto(s)
Biotecnología , Productos Agrícolas/genética , Plantas Modificadas Genéticamente/genética , Agricultura , Productos Agrícolas/química , Productos Agrícolas/inmunología , Productos Agrícolas/microbiología , Resistencia a la Enfermedad , Abastecimiento de Alimentos , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Plantas Modificadas Genéticamente/química , Plantas Modificadas Genéticamente/inmunología , Plantas Modificadas Genéticamente/microbiologíaRESUMEN
One of the major sugars present in the plant cell wall is d-galacturonate, the dominant monosaccharide in pectic polysaccharides. Previous work indicated that one of the activated precursors necessary for the synthesis of pectins is UDP-d-galacturonate, which is synthesized from UDP-d-glucuronate by a UDP-d-glucuronate 4-epimerase (GAE). Here, we report the identification, cloning and characterization of a GAE6 from Arabidopsis thaliana. Functional analysis revealed that this enzyme converts UDP-d-glucuronate to UDP-d-galacturonate in vitro. An expression analysis of this epimerase and its five homologs in the Arabidopsis genome by quantitative RT-PCR and promoter::GUS fusions indicated differential expression of the family members in plant tissues and expression of all isoforms in the developing pollen of A. thaliana.