ABSTRACT
Common bean is a crop recalcitrant to in vitro regeneration and therefore it lacks an efficient transformation protocol that can be reproduced using A. tumefaciens. The main goal of this study was to establish a protocol for A. tumefaciens mediated transformation of Phaseolus vulgaris var. Brunca by marker genes (gusA and nptII) together with the gene for trehalose-6-phosphate synthase from Saccharomyces cerevisiae (TPS1) used in other species to increase tolerance to abiotic stress. The β-glucuronidase activity was detected in 45 % of the LBA4404 ElectroMAX® pCAMBIA1301 infected explants. Transformed explants regenerated new shoots after four to five months period in a kanamycin rich media. Surviving plants were evaluated by PCR and presented an 0.5 % efficiency of transformation. The established protocol for genetic transformation of common bean has two additional advantages with respect to previous reports: (1) it allows for obtaining transformed regenerants and (2) the genetic transformation was stable for the selective gene.
El frijol común en un cultivo recalcitrante a la regeneración in vitro y se carece de un protocolo eficiente y reproducible de transformación genética usando A. tumefaciens. Desarrollamos un protocolo de transformación genética mediada por A. tumefaciens de frijol común variedad Brunca utilizando genes marcadores (gusA y nptII) junto con el gen de la trehalosa-6-fosfato sintasa de levadura (TPS1) utilizado para incrementar tolerancia a estrés abiótico. La actividad de la β-glucoronidasa fue detectada en 45 % de los explantes infectados con la cepa LBA4404 de A. tumefaciens transformada con pCAMBIA1301. Después de 4 o 5 meses se regeneraron tallos en un medio adicionado con kanamicina. Los explantes supervivientes se evaluaron mediante PCR y presentaron una eficiencia de transformación de 0.5 %. El protocolo de transformación genética de frijol común establecido tiene dos ventajas adicionales con respecto a los reportes previos: (1) permite la obtención de regenerares transformados y (2) la transformación genética fue estable para el gen selectivo.
ABSTRACT
J. curcas has been studied in different countries and some interesting agronomic, pharmacological and industrial properties have been reported. More recently, it has been considered an important alternative source for biofuel production. The objective of this study was to establish a long-term method for the maintenance of calli and cell suspension cultures of the local species J. curcas and J. gossypifolia, in order to allow future studies for novel compounds with pharmaceutical or industrial applications. For this, friable calli were successfully induced from hypocotyl segments of J. curcas and J. gossypifolia that were cultured in semisolid MS media supplemented with 1.5mg/L, and 0.5mg/L of 2,4-D, respectively. Cell suspension cultures of J. curcas were established using 1g of 35 and 60-day calli, in 50mL of liquid MS media supplied with 1.5mg/L of 2,4-D; sucrose and maltose were additionally evaluated as carbon sources. After 35 days, cell suspension cultures initiated with 35-day calli, showed greater cell growth with a maximum biomass of 194.9g/L fresh weight, 6.59g/L dry weight and 17.3% packed volume. The exponential phase ended at day 35 for cultures initiated with 35-day calli, and at day 21 for cultures initiated with 60-day calli. Higher biomass production was obtained with sucrose. Cell cultures were established with 35-day calli in MS media with the same 2,4-D concentration used for calli induction and 30g/L sucrose. This medium was considered optimum for the maintenance and growth of cell suspensions for both species, with sub-cultures every 20 days. The biotechnological potential for the production of bioactive compounds in these species for pharmacological, agricultural and industrial applications is being evaluated.
J. curcas es un importante recurso alternativo de biocombustible. Por otro lado, propiedades de interés agronómico, farmacológico e industrial han sido reportadas para esta especie. El objetivo de este estudio fue el establecimiento y mantenimiento a largo plazo de callos y cultivos celulares en suspensión de J. curcas y J. gossypifolia, con el objetivo de permitir futuros estudios para nuevos compuestos con aplicaciones farmaceúticas e industriales. Los callos friables fueron exitosamente inducidos a partir de segmentos de hipocótilos J. curcas and J. gossypifolia cultivados en medio MS semisólido suplementado con 1.5mg/L y 0.5mg/L of 2,4-D, respectivamente. Los cultivos celulares en suspensión de J. curcas fueron establecidos utilizando 1g de callos de 35 y 60 días de edad en 50mL de medio MS líquido adicionado con 1.5mg/L de 2,4-D. Después de 35 días, los cultivos en suspensión celular iniciados con callos de 35 días, mostraron mayor crecimiento celular con una biomasa máxima de 194.9g/L de peso fresco y 6.59g/L de peso seco y 17.3% de volumen empacado. La fase exponencial finalizó al día 35 en los cultivos iniciados con callos de 35 días, y al día 21 en los cultivos iniciados con callos de 60 días. Dos fuentes de carbono fueron evaluadas: sacarosa y maltosa. La producción de mayor biomasa fue obtenida con sacarosa. Los cultivos celulares se establecieron con callos de 35 días cultivados en medio MS con la misma concentración de 2,4-D utilizada para la inducción de callos y 30g/L de sacarosa. Este medio fue considerado el óptimo para el mantenimiento y crecimiento de suspensiones celulares en ambas especies con subcultivos cada 20 días. El potencial biotecnológico para la producción de compuestos bioactivos en estas especies, para aplicaciones farmacológicas, agrícolas e industriales está siendo evaluado.
Subject(s)
Cell Culture Techniques/methods , Jatropha/growth & development , Biomass , Jatropha/drug effects , Maltose/administration & dosage , Suspensions , Sucrose/administration & dosage , Time Factors , /administration & dosageABSTRACT
The gene uidA, codes for beta-glucuronidase, which is one of the reporters more frequently utilized in transgenic plants. However, this can only be use if the selected organism does not present endogenous GUS-like activity. In tissues of C. chinense we found a GUS-like activity showing different levels of intensity. Histochemical screening showed that endogenous GUS-like activity decreased, or reduced significantly, in almost all tissues with exception of stament, when phosphate buffer was adjusted to pH 8. Subsequently, C. chinense zygotic embryo explants were transient transformed with Agrobacterium tumefaciens LBA4404 (pCAMBIA2301) and plantlets regenerated were histochemically stained in phosphate buffer pH 8. Observations of incubated tissues of C. chinense regenerants showed blue staining, suggesting expression of uidA. Incubated tissues of non-transformed regenerants did not show blue staining in phosphate buffer pH 8. The results show that for transformation experiments of C. chinense with uidA gene, pH 8 is recommended for histochemical staining.