Strategies to increase crop yields in a climate change scenario

[EN] The forecasted effects of climate change ¿ higher average temperatures, more intense and frequent droughts, increasing scarcity of water for irrigation ¿ will worsen the problem of stress-induced reduction of crop yields, especially in arid regions. Development of new crop cultivars with enhanced tolerance to drought and salinity is probably the most promising strategy to improve agricultural productivity and food production. Some recent examples predict that this goal will be achieved in the near future using both, traditional breeding (with the help of new biotechnological tools) and genetic engineering. A complementary strategy could be based on the domestication of wild species naturally tolerant to stress. Optimizing plant nutrition with new and improved fertilizers will also contribute to stress tolerance of our present crops, as more resources will be available to maintain growth while activating defense mechanisms. There is also an increasing interest in the so-called `biostimulants¿, a disparate group of unrelated substances that enhance crop quality traits, nutrition efficiency and/or abiotic stress tolerance, also contributing to increased yields under stress conditions. Examples of all these strategies are presented and discussed.Boscaiu, M.; Naranjo Olivero, MA.; Vicente, O. (2018). Strategies to increase crop yields in a climate change scenario. Scientific Bulletin. Series F. Biotechnologies (Online). 22:15-20. http://hdl.handle.net/10251/123232S15202

Comparative analysis of water deficit and salt tolerance mechanisms in Silene

[EN] Comparative analyses of the responses to abiotic stress in related taxa with different degrees of tolerance can provide useful information to elucidate the mechanisms of stress tolerance in plants. This kind of study has been carried out in four Silene species, which were subjected to salt and water deficit treatments under controlled greenhouse conditions. Growth parameters and leaf levels of photosynthetic pigments, ions, osmolytes, malondialdehyde (MDA, an oxidative stress biomarker), total phenolic compounds and flavonoids, were determined in control and stressed plants. The degree of stress-induced growth inhibition allowed establishing the relative tolerance of the studied species, identifying S. vulgaris as the most tolerant to salinity and S. sclerocarpa to water deficit; these data correlated well with the characteristics of their natural habitats. All four species showed a high resistance to stress-induced leaf dehydration, and a good negative correlation was found between tolerance and the degradation of photosynthetic pigments. Salinity tolerance is mostly based on the inhibition of Na+ transport to the leaves and the maintenance of relatively high leaf K+ levels in the salt-treated plants. Proline is a reliable stress biomarker but does not appear to be involved in tolerance mechanisms in this genus, as it accumulates at higher levels in the more sensitive species.MDA contents did not increase significantly in response to the stress treatments ¿ except in water-stressed S. latifolia, the species most affected by water deficit ¿ suggesting that the plants were not affected by secondary oxidative stress under the experimental conditions used. Accordingly, the measured variations in the levels of total phenolic compounds and flavonoids were not statistically significant or did not correlate with the relative stress resistance of the studied species. Therefore, stress responses based on the activation of antioxidant systems do not seem to be relevant for abiotic stress tolerance in Silene.The work was supported in part by the Ministry of Science and Higher Education of The Republic of Poland as DS 3500/ZBiFR-IBRiB-WBiO-UR and the Erasmus+ Programme grants, for Aleksandra Kozminska to complete her doctoral studies.Kozminska, A.; Al Hassan, M.; Hanus-Fajerska, E.; Naranjo Olivero, MA.; Boscaiu, M.; Vicente, O. (2018). Comparative analysis of water deficit and salt tolerance mechanisms in Silene. South African Journal of Botany. 117:193-206. https://doi.org/10.1016/j.sajb.2018.05.022S19320611

SARS-CoV-2 viral load analysis at low and high altitude: A case study from Ecuador

SARS-CoV-2 has spread throughout the world, including remote areas such as those located at high altitudes. There is a debate about the role of hypobaric hypoxia on viral transmission and COVID-19 incidence. A descriptive cross-sectional analysis of SARS-CoV-2 infection and viral load among patients living at low (230 m) and high altitude (3800 m) in Ecuador was completed. Within these two communities, the total number of infected people at the time of the study was 108 cases (40.3%). The COVID-19 incidence proportion at low altitude was 64% while at high altitude was 30.3%. The mean viral load from those patients who tested positive was 3,499,184 copies/mL (SD = 23,931,479 copies/mL). At low altitude (Limoncocha), the average viral load was 140,223.8 copies/mL (SD = 990,840.9 copies/mL), while for the high altitude group (Oyacachi), the mean viral load was 6,394,789 copies/mL (SD = 32,493,469 copies/mL). We found no statistically significant differences when both results were compared (p = 0.056). We found no significant differences across people living at low or high altitude; however, men and younger populations had higher viral load than women older populations, respectivel

A comparative analysis of SARS-CoV-2 viral load across different altitudes

SARS-CoV-2 has spread throughout the world, including areas located at high or very high altitudes. There is a debate about the role of high altitude hypoxia on viral transmission, incidence, and COVID-19 related mortality. This is the first comparison of SARS-CoV-2 viral load across elevations ranging from 0 to 4300 m. To describe the SARS-CoV-2 viral load across samples coming from 62 cities located at low, moderate, high, and very high altitudes in Ecuador. An observational analysis of viral loads among nasopharyngeal swap samples coming from a cohort of 4929 patients with a RT-qPCR test positive for SARS-CoV-2. The relationship between high and low altitude only considering our sample of 4929 persons is equal in both cases and not significative (p-value 0.19). In the case of low altitude, adding the sex variable to the analysis, it was possible to find a significative difference between men and women (p-value < 0.05). Considering initially sex and then altitude, it was possible to find a significative difference between high and low altitude for men (p-value 0.05). There is not enough evidence to state that viral load is affected directly by altitude range but adding a new variable as sex in the analysis shows that the presence of new variables influences the relationship of altitude range and viral load. There is no evidence that viral loads (Ct and copies/ml) differ at low or high altitude. Using sex as a co-factor, we found that men have higher viral loads than women at low and moderate altitude locations, while living at high altitude, no differences were found. When Ct values were aggregated by low, moderate, and high viral load, we found no significant differences when sex was excluded from the analysis. We conclude that viral load is not directly affected by altitude, but COVID-19 incidence and mortality are rather affected by socio-demographic and idiosyncratic dynamics

Método de evaluación de la eficacia de genes de tolerancia a estrés abiótico en plantas transgénicas

Fecha de solicitud: 10/04/2008.- Titular: Consejo Superior de Investigaciones Científicas (CSIC)The invention relates to a method for assessing the efficiency of abiotic stress tolerance genes, involving the phenotype analysis of the expression thereof in transgenic plants, in which: a) a structure is obtained, comprising a stress tolerance gene and a specific pollen promoter both contained in a vector for genetic plant transformation; b) a plant species with the aforementioned structure is transformed to obtain a transgenic plant; c) mature pollen from said plant is isolated; d) an in vitro germination culture is obtained from the isolated pollen by incubating same in a liquid medium; e) abiotic stress treatments are applied to the culture; and f) tolerance to the stress applied to said pollen culture is analysed and compared with that of a pollen culture from a non-transformed control plant subjected to the same stress conditions.El la invención se refiere a un método para evaluar la eficacia de los genes abiotic de la tolerancia del esfuerzo, implicando la análisis del fenotipo de la expresión de eso en las plantas transgénicas, en las cuales: a) se obtiene una estructura, comprendiendo a un gen y a un promotor específico ambos de la tolerancia del esfuerzo del polen contenidos en un vector para la transformación genética de la planta b) las especies de plantas con la estructura mencionada se transforman para obtener una planta transgénica c) el polen maduro de la planta dicha se aísla d) un cultivo in vitro de la germinación es obtenido del polen aislado incubando mismo en un medio líquido e) el son abiotic de los tratamientos del esfuerzo aplicó al cultivo y la tolerancia de f) al esfuerzo aplicó al cultivo dicho del polen se analiza y se compara con la de un cultivo del polen de una planta de control no-transformada sometida a las mismas condiciones del esfuerzo.Peer reviewe