RESUMEN
Transgenic plants are commonly used in breeding programs because of the various features that can be introduced. However, unintended effects caused by genetic transformation are still a topic of concern. This makes research on the nutritional safety of transgenic crop plants extremely interesting. Cucumber (Cucumis sativus L.) is a crop that is grown worldwide. The aim of this study was to identify and characterize differentially expressed genes and regulatory miRNAs in transgenic cucumber fruits that contain the thaumatin II gene, which encodes the sweet-tasting protein thaumatin II, by NGS sequencing. We compared the fruit transcriptomes and miRNomes of three transgenic cucumber lines with wild-type cucumber. In total, we found 47 differentially expressed genes between control and all three transgenic lines. We performed the bioinformatic functional analysis and gene ontology classification. We also identified 12 differentially regulated miRNAs, from which three can influence the two targets (assigned as DEGs) in one of the studied transgenic lines (line 224). We found that the transformation of cucumber with thaumatin II and expression of the transgene had minimal impact on gene expression and epigenetic regulation by miRNA, in the cucumber fruits.
Asunto(s)
Cucumis sativus/genética , Técnicas de Transferencia de Gen/efectos adversos , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente/genética , Transcriptoma , Frutas/genética , Frutas/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Proteínas de Plantas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
The metabolic profiles of five transgenic cucumber lines were compared taking into consideration their transgene integration sites. The plants analyzed were homozygous and contained transgenes integrated in a single locus on chromosomes I, II, III or IV. The transgenes were preferentially located in the euchromatic regions. Each of these locations possessed a specific metabolic profile. The number of altered compounds in the transgenic lines varied between 9 and 23 of the 47 metabolites identified. These alterations seem to be specific for each independent transgene integration. However, some changes are common: a decrease in the levels of phenylalanine, aspartate, ethanolamine and pipecolate, and an increase in the level of benzoic acid. The observed effects of transgene introduction are discussed in this paper.
Asunto(s)
Cromosomas de las Plantas/genética , Cucumis sativus/genética , Cucumis sativus/metabolismo , Transgenes/genética , Bandeo Cromosómico , Hibridación Fluorescente in Situ , Metafase , Hojas de la Planta/metabolismo , Plantas Modificadas GenéticamenteRESUMEN
A phenotypic segregation of kanamycin resistance conferred by nosnptII was investigated in two groups of transgenic cucumber lines one containing the PR-2duidA-nosnptII construct and the other with the thaumatinII-nosnptII construct to the third and fifth generation, respectively. Expression of the nptII gene was more stable and predictable in the progeny of the PR-2d lines than that of thaumatin lines. In T2 and T3 generations representing seven PR-2d primary transformants, 78% of the hemizygous progenies exhibited a segregation ratio consistent with Mendelian inheritance; non-Mendelian ratio occurred in the remaining 22%. Mendelian segregation was observed in 46% of the hemizygous progenies derived from 11 thaumatin primary transformants. The segregation ratio for two and three independent loci appeared in single PR-2d and thaumatin lines, respectively.
Asunto(s)
Cucumis sativus/genética , Resistencia a la Kanamicina/genética , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente/fisiología , Cruzamientos Genéticos , Técnicas de Transferencia de Gen , Modelos Genéticos , Plantones/genéticaRESUMEN
The PR-2d promoter/uidA (GUS) gene construct was introduced into the cucumber (Cucumis sativus L.) genome and several transgenic lines were produced. Activation of the PR-2d promoter was investigated in these plants in response to inoculation with fungal pathogens and after salicylic acid (SA) or cold treatments. Treatment with exogenous SA increased GUS activity 2 to 11 fold over that of the control. Endogenous SA and its conjugate salicylic acid glucoside (SAG) rose in parallel after inoculation with the fungal pathogen Pseudoperonospora cubensis, with SAG becoming the predominant form. The free SA levels increased 15 fold above the basal level at 5 dpi and preceded the induction of the PR-2d promoter by five days, which occurred at 10 dpi with a 12 fold increase over the control. Inoculation with another fungal pathogen, Erysiphe polyphage, increased GUS activity 4 to 44 fold over that of the control. During normal development of flowers in the cucumber, the PR-2d/uidA gene expressed in the floral organs was similar to that of the primary host. In addition, we present the first evidence that the PR-2d promoter was induced (624 fold) under cold stress. We demonstrate that in the heterologous state the gene construct was expressed according to the signalling pattern of the native species and was stably transmitted to progeny over four generations.