Jorge Alberto Acosta-Gallegos

Photosynthesis and chloroplast genes are involved in water-use efficiency in common bean.

A recent proposal to mitigate the effects of climatic change and reduce water consumption in agriculture is to develop cultivars with high water-use efficiency. The aims of this study were to characterize this trait as a differential response mechanism to water-limitation in two bean cultivars contrasting in their water stress tolerance, to isolate and identify gene fragments related to this response in a model cultivar, as well as to evaluate transcription levels of genes previously identified. Keeping CO2 assimilation through a high photosynthesis rate under limited conditions was the physiological response which allowed the cultivar model to maintain its growth and seed production with less water. Chloroplast genes stood out among identified genetic elements, which confirmed the importance of photosynthesis in such response. ndhK, rpoC2, rps19, rrn16, ycf1 and ycf2 genes were expressed only in response to limited water availability.

‘Dalia’, nueva variedad de frijol de grano tipo Flor de Junio para la región centro de México

El frijol tipo Flor de Junio, cuyo color de grano es de fondo crema con franjas rosas, se produce y consume en la region Centro de Mexico. Se describe el proceso de obtencion y caracteristicas de Dalia, una nueva variedad de frijol tipo Flor de Junio de raza Jalisco, derivada de la cruza de Flor de Junio Silvia por Flor de Mayo Anita realizada en el Campo Experimental Bajio en 2003. El proceso de seleccion se baso inicialmente en la sanidad y el ciclo de la planta, asi como en las caracteristicas comerciales del grano en siembras bajo condiciones alternas de riego y temporal. En su fase final se realizo seleccion asistida por marcadores moleculares (SAM) para seleccionar la progenie que tuviera simultaneamente los marcadores ROC11 y SW13, ligados a los genes I y bc3, cuya piramidacion confieren resistencia a todos los patotipos de los virus BCMV y BCMNV. Dalia es de habito de crecimiento indeterminado tipo 3, con guias de tamano medio y ciclo de cultivo intermedio de 105 dias de siembra a la madurez fisiologica, y resistente a BCMV y BCMNV. En un ensayo nacional de rendimiento y adaptacion, Dalia mostro un rendimiento similar a Flor de Junio Marcela, la variedad dominante en el mercado, pero en contraste con esta, una nula interaccion genotipo por ambiente, lo que indico amplia adaptacion y estabilidad de rendimiento. Dalia se recomienda para produccion bajo riego y temporal en las regiones de El Bajio y el Altiplano del centro de Mexico.

Junio León, nueva variedad de frijol para riego y temporal el Altiplano y la Mesa Central de México

Resumen El frijol de tipo Flor de Junio es de alta demanda en la region centro de Mexico; es producido bajo condiciones de riego y temporal en los estados de Zacatecas, San Luis Potosi y Guanajuato, principalmente. La nueva variedad Junio Leon se derivo de la cruza simple de Flor de Junio Marcela por Flor de Mayo Anita realizada en 2004 en el Campo Experimental Bajio. Es de habito indeterminado-postrado y se adapta bien en siembras a doble hilera o en hilera sencilla. El grano es de tamano medio (34 g en 100 granos), de fondo crema y rayas rosa. Es resistente al tizon comun y tizon de halo y bajo temporal presenta una incidencia menor (1.8) de roya, en comparacion con Flor de Junio Marcela (4). Junio Leon posee los marcadores asociados a los genes Ur 6 y Ur 9 , de origen Andino, genes importantes porque en combinacion con los genes de origen Mesoamericano que posee ( Ur 3, Ur 4, Ur 5 y GB ), muestran un amplio espectro de resistencia a la roya. En contenido de proteina, el grano de Junio Leon fue superior al de Marcela en condiciones de riego y similar bajo temporal, asi mismo, el tiempo de coccion resulto similar bajo ambas condiciones.

Simultaneous Detection of Both RNA and DNA Viruses Infecting Dry Bean and Occurrence of Mixed Infections by BGYMV, BCMV and BCMNV in the Central-West Region of Mexico

A multiplex reverse transcription polymerase chain reaction (RT-PCR) assay was developed to simultaneously detect bean common mosaic virus (BCMV), bean common mosaic necrotic virus (BCMNV), and bean golden yellow mosaic virus (BGYMV) from common bean leaves dried with silica gel using a single total nucleic acid extraction cetyl trimethyl ammonium bromide (CTAB) method. A mixture of five specific primers was used to amplify three distinct fragments corresponding to 272 bp from the AC1 gene of BGYMV as well as 469 bp and 746 bp from the CP gene of BCMV and BCMNV, respectively. The three viruses were detected in a single plant or in a bulk of five plants. The multiplex RT-PCR was successfully applied to detect these three viruses from 187 field samples collected from 23 municipalities from the states of Guanajuato, Nayarit and Jalisco, Mexico. Rates of single infections were 14/187 (7.5%), 41/187 (21.9%), and 35/187 (18.7%), for BGYMV, BCMV, and BCMNV, respectively; 29/187 (15.5%) samples were co-infected with two of these viruses and 10/187 (5.3%) with the three viruses. This multiplex RT-PCR assay is a simple, rapid, sensitive, and cost-effective method for detecting these viruses in the common bean and can be used for routine molecular diagnosis and epidemiological studies.

First Report of Cowpea mild mottle virus Infecting Cultivated and Wild Phaseolus in the Central-Western Region of Mexico

In the context of a regional project with the aim of identifying viruses infecting cultivated Phaseolus vulgaris (CB) and wild bean (WB): P. vulgaris, P. coccineus and P. leptostachyus species in the central-western region of Mexico, six leaves from 394 CB and 245 WB plants with (74%) and without (26%) viral symptoms were collected in the Mexican states of Guanajuato, Jalisco and Nayarit between 2013-2015. The symptoms observed were chlorotic lesions, mild and severe mottling, mild mosaics and leaf deformation. To identify the viruses, small RNA sequencing and an assembly technique was used (Kreuze, 2014). Small RNA (sRNA) reads with identity to Cowpea mild mottle virus (CPMMV) and Bean common mosaic necrosis virus (BCMNV) were identified in the sRNA library CN2Ls prepared from one sample of Phaseolus vulgaris cv. ‘Coranay’ collected in Nayarit state (CN2, NCBI BioProject: PRJNA362733), whose leaves exhibited mottling, mild mosaic and slight deformation symptoms. After bioinformatic processing and assembl...