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Agrobacterium-mediated genetic transformation is the most widely used technology to obtain overexpression of recombinant proteins in plants. Molecular events that occur within Agrobacterium during interactions with host plants have been studied extensively, and now we have a reasonable understanding the key factors involved in the regulation of T-DNA nuclear import and genomic integration. By contrast, very little is known about the events that take place in the host cells during genetic transformation by Agrobacterium. Here, we describe the plant-related factors including genotype, genes, proteins, competency of target tissues and phenolic compounds that participate in Agrobacteriummediated genetic transformation and discuss their possible roles in this process. Because Agrobacterium probably adapts existing cellular processes for its life cycle, identifying the processes in host cells during Agrobacterium infection might contribute to better understanding of basic biological processes as cell communication, intracellular transport and DNA repair and recombination as well as to expanding the host range of Agrobacterium as a genetic engineering tool.

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Thin layer drying characteristics of high moisture corn under fixed, semi fluidized and fluidized bed conditions with high initial moisture content (66.82% wb) in a laboratory fluidized bed convective dryer was studied at air temperatures of 50, 65, 80 and 95°C. In order to find a suitable drying curve, seven thin layer-drying models were fitted to the experimental data of moisture ratio. Among the applied mathematical models, Midilli et al. model was the best for drying behavior prediction in corn thin layer drying. This model presented high values for correlation coefficient (R 2 ). Fick´s second law was used to compute moisture diffusivity with some simplifications. Computed values of moisture diffusivity varied at the boundary of 4.87 × 10 -11 -2.90 × 10 -10 m 2 s -1 and 1.02 × 10 -10 -1.29 × 10 -9 m 2 s -1 during the first and second drying falling-rate, respectively. Values of effective moisture diffusivity for corn were also increased as input air temperature was increased. Value of activation energy varied from a minimum of 18.57 to a maximum of 50.74 kJ mol -1 from 50 to 95°C with drying conditions of fixed to fluidized bed. Specific energy consumption (SEC) for thin-drying of high moisture corn was found to be in the range of 0.33 × 10 6 -1.52 × 10 6 kJ kg -1 from 50 to 95°C with drying condition of fluidized and fixed bed, respectively. Increase in air temperature in each air velocity caused decrease in SEC value. These corn properties would be necessary to design the best dryer system and to determine the best point of drying process.Additional key words: drying; maize; Midilli et al. model; semi fluidized. ResumenModelización de la difusividad de la humedad, la energía de activación y el consumo específico de energía para el grano de maíz húmedo en un secador convectivo de lecho fijo y fluidizado Se estudiaron las características del secado en capa delgada del grano de maíz húmedo en condiciones de lecho fijo, semi-fluidizado y fluidizado con alto contenido de humedad inicial (66,82%), en un secador de convección de lecho fluidizado de laboratorio a las temperaturas del aire de 50, 65, 80 y 95°C. Con el fin de encontrar una curva de secado apropiada, se ajustaron siete modelos matemáticos de secado en capa delgada a los datos experimentales de la ratio de humedad. Entre los modelos aplicados, el de Midilli et al., con un alto coeficiente de correlación (R 2 ), fue el mejor para predecir el secado del maíz en capa delgada. Se utilizó la segunda ley de Fick para calcular, con algunas simplificaciones, la difusividad de la humedad, que dio unos valores entre 4,87 × 10 -11 -2.90 y 1,02 × 10 -11 -1.29 m 2 s -1 durante la primera y segunda fase de secado de rapidez decreciente, respectivamente. Los valores de la difusividad efectiva de la humedad para el maíz también aumentaron al aumentar la temperatura de entrada del aire. El valor de la energía de activación varió desde un mínimo de 18,57 a un máximo de 50,74 kJ mol -1 entre 50 y 95°C, con condiciones de secado del lecho fijo a fluidizado. El c...