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To recover transgenic citrus plants in the most efficient manner, the use of selection marker genes is essential. In this work, it was shown that the mutated forms of the acetolactate synthase (ALS) gene in combination with the herbicide selection agent imazapyr (IMZ) added to the selection medium may be used to achieve this goal. This approach enables the development of cisgenic regenerants, namely, plants without the incorporation of those bacterial genes currently employed for transgenic selection, and additionally it allows the generation of edited, non-transgenic plants with altered endogenous ALS genes leading to IMZ resistance. In this work, the citrus mutants, in which ALS has been converted into IMZ-resistant forms using a base editor system, were recovered after cocultivation of the explants with Agrobacterium tumefaciens carrying a cytidine deaminase fused to nSpCas9 in the T-DNA and selecting regenerants in the culture medium supplemented with IMZ. Analysis of transgene-free plants indicated that the transient expression of the T-DNA genes was sufficient to induce ALS mutations and thus generate IMZ-resistant shoots at 11.7% frequency. To our knowledge, this is the first report of T-DNA-free edited citrus plants. Although further optimization is required to increase edition efficiency, this methodology will allow generating new citrus varieties with improved organoleptic/agronomic features without the need to use foreign genes.

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Huanglongbing (HLB), formerly known as greening, is a bacterial disease restricted to some Asian and African regions until two decades ago. Nowadays, associated bacteria and their vectors have spread to almost all citrus-producing regions, and it is currently considered the most devastating citrus disease. HLB management can be approached in terms of prevention, limiting or avoiding pathogen and associated vectors to reach an area, or in terms of control, trying to reduce the impact of the disease by adopting different cultural strategies depending on infestation/infection levels. In both cases, control of psyllid populations is currently the best way to stop HLB spread. Best cultural actions (CHMAs, TPS system) to attain this goal and, thus, able to limit HLB spread, and ongoing research in this regard is summarized in this review.

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BACKGROUND: The prevalence of allergic diseases has increased worldwide. Recent studies have informed that the dysbiosis of some specific members of the human microbiota may enhance the allergic response of the respiratory tract. OBJECTIVE: To retrospectively explore the role of some microorganisms of the human microbiota on the skin reactivity and their effect on the chronicity of allergic respiratory diseases in humans. METHODS: A retrospective analysis of a 5-year database of patients with allergic respiratory tract disease. The frequency and magnitude of the reactivity to 38 different allergens was determined. RESULTS: Dermatophagoides pteronyssinus had the highest frequency of reactivity (93.7 %), followed by the bacterial allergen (a mixture of Staphylococcus aureus and Staphylococcus epidermidis) with a frequency of reactivity of 91.82 %; whereas Candida albicans had a frequency of reactivity of only 79.32 %. The frequency of reactivity to the pollen of native Mexican weeds was even lower ~79 %. CONCLUSION: The microorganisms of the microbiota that were analyzed in this study seem to have an influence on the development of respiratory allergic inflammation, associated with long-term colonization of the pharynx, nasal mucosa, and sinuses because of these microorganisms.

Antecedentes: La prevalencia de las enfermedades alérgicas ha aumentado en todo el mundo. En estudios recientes se ha informado que la disbiosis de algunos miembros específicos de la microbiota humana puede potenciar la respuesta alérgica de las vías respiratorias. Objetivo: Explorar retrospectivamente el papel de algunos microorganismos de la microbiota humana en la reactividad cutánea y su efecto sobre la cronicidad de las enfermedades alérgicas respiratorias en el humano. Métodos: Análisis retrospectivo de la base de datos de un periodo de cinco años de pacientes con enfermedad alérgica de las vías respiratorias. Se determinó la frecuencia y magnitud de la reactividad a 38 alérgenos diferentes. Resultados: La mayor frecuencia de reactividad la presentó Dermatophagoides pteronyssinus (93.7 %), al que le siguió una combinación bacteriana de Staphylococcus aureus-Staphylococcus epidermidis (91.82 %) y Candida albicans (79.32 %). La reactividad a alérgenos de polen de malezas nativas de México fue aun menor, aproximadamente de 79 %. Conclusión: Los microorganismos de la microbiota analizados en este estudio parecen tener una influencia en el desarrollo de la inflamación alérgica respiratoria, asociada a la colonización a largo plazo de la faringe, la mucosa nasal y los senos paranasales.

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'Cara Cara' is a red orange (Citrus sinensis (L.) Osbeck) variety originally from Venezuela characterized by a significantly higher and diversified carotenoid content including higher-concentration lycopene, all-E-ß-carotene, phytoene, and other carotenoids when compared with the carotenoid profile of its isogenic blond counterpart 'Bahia', also known as Washington navel. The exceptionally high carotenoid content of 'Cara Cara' is of special interest due to its neuroprotective potential. Here, we used the nematode Caenorhabditis elegans to analyze the antioxidant effect and the protection against ß-amyloid-induced toxicity of pasteurized orange juice (POJ) obtained from 'Cara Cara' and compare to that from 'Bahia'. POJ treatment reduced the endogenous ROS levels and increased the worm's survival rate under normal and oxidative stress conditions. POJ treatment also upregulated the expression of antioxidant (gcs-1, gst-4, and sod-3) and chaperonin (hsp-16.2) genes. Remarkably, ROS reduction, gene expression activation, oxidative stress resistance, and longevity extension were significantly increased in the animals treated with 'Cara Cara' orange juice compared to animals treated with 'Bahia' orange juice. Furthermore, the body paralysis induced by ß-amyloid peptide was delayed by both POJs but the mean paralysis time for the worms treated with 'Cara Cara' orange juice was significantly higher compared to 'Bahia' orange juice. Our mechanistic studies indicated that POJ-reduced ROS levels are primarily a result of the direct scavenging action of natural compounds available in the orange juice. Moreover, POJ-induced gst-4::GFP expression and -increased stress resistance was dependent of the SKN-1/Nrf2 transcription factor. Finally, the transcription factors SKN-1, DAF-16, and HSF-1 were required for the POJ-mediated protective effect against Aß toxicity. Collectively, these results suggest that orange juice from 'Cara Cara' induced a stronger response against oxidative stress and ß-amyloid toxicity compared to orange juice from 'Bahia' possibly due to its higher carotenoid content.

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Background: Brettanomyces bruxellensis is an important spoilage yeast in the winemaking process. The capacity of this yeast to generate an undesired off-flavor constitutes a significant loss in the Chilean wine industry. Results: The proteomic profile of B. bruxellensis in the presence of p-coumaric acid was determined by 2D gel electrophoresis, gel image analysis and differential spot selection. A set of 41 proteins showed a differential accumulation of ±2 and a p-value <0.0001. The homology sequence analysis was performed using the databases available. Differential proteins belonged to the categories of 'energy production and conversion' and 'amino acid transport and metabolism'. Conclusions: The proteomic profile of B. bruxellensis cultivated in the presence of p-coumaric acid in synthetic wine, agrees with the hypothesis of metabolic flux regulation, allowing a better conditioning to an adverse environment. This study involved the translational level of B. bruxellensis in the production of ethylphenols and corroborated that this yeast presented an advantage in these stress conditions. Thus, this work will allow an understanding of the regulation and processes involved in the production of ethyl-derivate compounds by B. bruxellensis. Furthermore, it allows the development of newer and better techniques for spoilage yeast control.

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