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Barria, P., Ocampo-Melgar, A., Chadwick, C., Galleguillos, M., Garreaud, R., Diaz-Vasconcellos, R., et al. (2022). Comment on: “The impact of a lack of government strategies for sustainable water management and land use planning on the hydrology of water bodies: lessons learned from the disappearance of the Aculeo Lagoon in central Chile” by Valdes-Pineda et al. 2022 in Sustainability, 14(1), 413. Reg. Environ. Change, 22(4), 131.
Abstract: Valdes-Pineda et al. (Sustainability 14:413, 2022) present data for changes in climate, socio-economic, and land use and land cover (LULC) from diverse sources, concluding that the main causes for the desiccation of the Aculeo Lake were the river deviations and aquifer pumping, along with the impact of reduced precipitation. Based on that, they infer that the previous study of Barria et al. (Reg Environ Change 21:1-5, 2021a), which concluded that the impact of the decade-long drought was ten times larger than the increase of human extractions on the lake desiccation lacks scientific validity. We disagree with the conclusions from Valdes-Pineda et al. (Sustainability 14:413, 2022) and document that their article uses fragmentary information of a complex system, misinterprets of our results, and fails to present a reliable attribution methodology. We show that the hypothesis that the disappearance of Aculeo Lake was largely due to local anthropogenic uses is unsupported.
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de la Guardia, A. R. H., Ugalde, M. B., Lobos-Diaz, V., Romero-Romero, J. L., Meyer-Regueiro, C., Inostroza-Blancheteau, C., et al. (2021). Isolation and molecular characterization of MYB60 in Solanum lycopersicum. Mol. Biol. Rep., 48(2), 1579–1587.
Abstract: Stomatal closure is a common adaptation response of plants to the onset of drought condition and its regulation is controlled by transcription factors. MYB60, a transcription factor involved in the regulation of light-induced stomatal opening, has been characterized in arabidopsis and grapevine. In this work, we studied the role of MYB60 homolog SIMYB60 in tomato plants. We identified, isolated, and sequenced the SIMYB60 coding sequence, and found domains and motifs characteristic of other MYB60 proteins. We determined that SlMYB60 is mainly expressed in leaves, and its expression is repressed by abscisic acid. Next, we isolated a putative promoter region containing regulatory elements responsible for guard cell expression and other putative regulatory elements related to ABA repression and vascular tissue expression. Protein localization assays demonstrated that SlMYB60 localizes to the nucleus. Finally, SlMYB60 is able to complement the mutant phenotype of atmyb60-1 in Arabidopsis. Together, these results indicate that SlMYB60 is the homologous gene in tomato and potentially offer a molecular target to improve crops.
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Ocampo-Melgar, A., Barria, P., Chadwick, C., & Diaz-Vasconcellos, R. (2022). Rural transformation and differential vulnerability: Exploring adaptation strategies to water scarcity in the Aculeo Lake basin. Front. Environ. Sci., 10, 955023.
Abstract: The way of life of agricultural rural territories and their long-term capacity to adapt to changes will be challenged not only by the impacts of climate change; but by increased vulnerability stemming from previous inadequate climate adaptations and development policies. Studies that deepen understanding of the differential causes and implications of vulnerabilities will improve adaptation or transformation of institutions for climate change. The Aculeo basin of Central Chile suffered an extreme 10-years rainfall deficit that resulted in the disappearance of a 12 km(2) lake and the economic transformation of the territory. This paper presents a cross-scale exploration of the political, cultural and historical interconnections behind this dramatic story, while critically discussing whether today's land use configuration reflects the territory's adaptive capacity. The story is reconstructed using land-use change analysis along with literature review and Causal-Loop Analysis. Results show how previous policies and other human factors contributed to the agroecosystem transformation, creating different vulnerabilities in different economic sectors. Today, what is observed as disparate capacities to adapt to climatic drought is actually the result of historic exacerbations of the vulnerabilities that had significantly contributed to the water scarcity crisis.
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Romero-Romero, J. L., Inostroza-Blancheteau, C., Orellana, D., Aquea, F., Reyes-Diaz, M., Gil, P. M., et al. (2018). Stomata regulation by tissue-specific expression of the Citrus sinensis MYB61 transcription factor improves water-use efficiency in Arabidopsis. Plant Physiol. Biochem., 130, 54–60.
Abstract: Water-use efficiency (WUE) is a quantitative measurement of biomass produced per volume of water transpired by a plant. WUE is an important physiological trait for drought response to mitigate the water deficiency. In this work, a cisgenic construction from Citrus sinensis was developed and its function in the improvement of WUE was evaluated in Arabidopsis. Sequences of the CsMYB61 coding region, a transcription factor implicated in the closure of stomata, together with a putative stomata-specific promoter from CsMYB.1.5, were identified and cloned. The protein encoded in the CsMYB61 locus harbors domains and motifs characteristic of MYB61 proteins. In addition, a 1.2 kb promoter region of the gene CsMYB15 (pCsMYB15) containing regulatory elements for expression in guard cells and in response to Abscisic Acid (ABA) and light was isolated. In Arabidopsis, pCsMYB15 directs the expression of the reporter gene GUS in stomata in the presence of light. In addition, transgenic lines expressing the CsMYB61 coding region under transcriptional control of pCsMYB15 have a normal phenotype under in vitro and greenhouse conditions. These transgenic lines exhibited a smaller opening of the stomata pore, lower stomatal conductance and respiration rate, enhanced sensitivity to exogenous ABA, and high drought stress tolerance. Our results indicate that stomata-specific expression of CsMYB61 enhances water use efficiency under drought conditions in Arabidospis.
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Romero-Romero, J. L., Inostroza-Blancheteau, C., Reyes-D?az, M., Matte, J. P., Aquea, F., Espinoza, C., et al. (2020). Increased Drought and Salinity Tolerance in Citrus aurantifolia (Mexican Lemon) Plants Overexpressing Arabidopsis CBF3 Gene. J. Soil Sci. Plant Nutr., 20(1), 244–252.
Abstract: Citrus are a globally important fruit crop. Abiotic stressors such as drought and salinity adversely affect physiological citrus performance and survival. With the aim of improving drought tolerance in citrus plants, we constructed transgenic lines of Citrus lemon overexpressing the Arabidopsis transcription factor CBF3. Molecular, physiological, and quantitative real-time analyses showed high expression of AtCBF3 in three selected transgenic lines. During a 15-day treatment of water deficit by cessation of irrigation, the transgenic lines LM2 and LM14 showed lower stomatal conductance and transpiration paired with lower photosynthesis, whereas transgenic line LM7 maintained its photosynthesis, declining stomatal conductance, and transpiration compared to WT plants, which is manifested into more efficient water use. The genes CsRafS1 and CsGolS1 showed similar or greater expression in one of the transgenic lines with respect to control plants. Moreover, transgenic lines were more tolerant to saline stress and presented a greener phenotype with increased chlorophyll content in leaf discs compared to WT plants. In addition, a lower electrical conductivity in solution was observed in transgenic lines. Furthermore, all transgenic lines exhibited significantly less accumulation of reactive oxygen species than WT plants. Together, these results suggest the potential for heterologous expression of the AtCBF3 gene to mediate tolerance to hydric and saline stress in citrus plants.
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