Induction of the expression of defence genes in Carica papaya fruit by methyl jasmonate and low temperature treatments

Abstract The defence mechanisms that are activated by methyl jasmonate (MJ) in fruits are not well understood. In this work, we studied the expression of defence genes in papaya fruit that are induced by the exposure to MJ and/or low temperatures. The papaya fruits \u2018Maradol\u2019 were randomly divided into two groups: one group was the untreated control and the other was treated with 10-4 M of MJ. Half of the fruits from each of the two groups were stored after treatment for 5 days at 5\ubaC and 2 days at 20\ubaC. We studied the expression levels of the pdf1.1 and pdf1.2 genes by amplification from expression libraries created from the pulp and skin tissues of the papaya fruit. As a reference, the mRNA level of the 18s ribosomal gene was used. In the skin tissue, the expression levels of the pdf1.1 and pdf1.2 genes were higher immediately after MJ treatment compared to the control. Furthermore, the expression of pdf1.2 remained high after MJ treatment and subsequent storage compared to the control. It was therefore concluded that the activation of the pdf1.1 and pdf1.2 genes forms part of the molecular defence mechanism in fruits that is activated by exposure to MJ. To our knowledge, this is the first study that analyzes the gene expression in papaya fruit that is induced by the exogenous application of methyl jasmonate and cold treatment

Detección de vibrio mediante la amplificación de genes de patogenicidad en camarón Litopenaeus vannamei cultivado en un sistema tipo invernadero

The infections by vibrio are an important problem in shrimp culture due to high mortalities and large economic losses caused. The aim of the study was to identify genes of pathogenicity in vibrio bacteria isolated of L. vannamei shrimp cultured in an intensive system on greenhouse with zero water exchange. It was determined total bacterial count and vibrio in hemolymph, hepatopancreas and gills of the shrimp. The strains were identified as Vibrio ssp., V. harveyi hemolysin gene (vhh), V. harveyi toxR and other pathogenic vibrio species by PCR. Both genes (hemolysin and toxR) were identified in four isolates of shrimp. This methodology could be a tool in the detection of V. harveyi for prevention and control. A highlight of this study was the absence of V. cholerae (V. chol), V. vulnificus (Vvh-785) y V. harveyi (LuxN), an important matter to the consumer health.Las infecciones por vibrio son un problema importante en el cultivo de camarón por la alta mortalidad y grandes pérdidas económicas provocadas. El objetivo del estudio fue identificar genes de patogenicidad en bacterias vibrio aisladas de camarón L. vannamei cultivado en un sistema intensivo tipo invernadero con nulo recambio de agua. Se determinó cuenta total bacteriana y de vibrio en hemolinfa, hepatopáncreas y branquias de camarón, de donde se obtuvieron aislados bacterianos para la identificación por PCR de Vibrio ssp., V. harveyi gen de hemolisina (vhh), V. harveyi toxR y otras especies patógenas de vibrio. Se identificaron ambos genes (hemolisina y toxR) en cuatro de los aislados de camarón. Esta metodología puede ser una herramienta en la detección de V. harveyi para su prevención y control. No se detectó V. cholerae (V. chol), V. vulnificus (Vvh-785) y V. harveyi (LuxN), aspecto importante desde el punto de vista de salud del consumidor

Efecto de los crioprotectores en la morfología y pérdida iónica en yemas axilares de vid cv. `Flame Seedless´ crioconservadas

The cryopreservation has revolutionized the field of biotechnology. Frozen in liquid nitrogen (LN) preserves long living cells. In this sense, in this paper were evaluated three conditions of cryopreservation based on vitrification of buds of grapevine. The buds were subjected to the PVS2, PVS3 and glycerol for 0-420 min, and submerged in LN for one hour. After the incubation time electrolyte leakage was determined as a viability measurement, and tissue damage was evaluated through stereoscopic observation. Based on the viability percentage the best preservation method was using PVS3 solution (30%) followed by glycerol (25%) and PVS2 (<10%). The images of the buds exposed to PVS3 shows no tissue damage unlike to PVS2 and glycerol, were not sufficient to preserve buds tissue. The results shown here suggest that using PVS3 as protocol can be considered for buds grapevine germplasm preservation.La crioconservación ha revolucionado el campo de la biotecnología. Congelar en nitrógeno líquido (NL) preserva células por largo tiempo. En ese sentido, en este trabajo se evaluaron tres condiciones de crioconservación basados en la vitrificación de yemas de vid. Las yemas fueron sometidas a PVS2, PVS3 y glicerol por 0-420 min, y colocadas en NL por una hora. De modo posterior a cada tiempo de incubación se cuantificó la pérdida de iones como medida de viabilidad y se evaluó el daño mediante observación en estereoscopio. Basados en el porcentaje de viabilidad el mejor método fue empleando PVS3 (30% viabilidad), seguido de glicerol (25%) y PVS2 (<10%). Las imágenes de las yemas expuestas a PVS3 no muestran daño en el tejido, a diferencia de PVS2 y glicerol, los cuales resultaron insuficientes para preservar el tejido. Estos resultados sugieren que el protocolo utilizando PVS3 puede ser considerado para la preservación de yemas de vid