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Summary: Aluminum (Al)-tolerant phosphobacteria enhance plant growth in acidic soils by improving Al complexing and phosphorus (P) availability. However, the impact of Al stress and P deficiency on bacterial biochemistry and physiology remains unclear. We investigated the single and mutual effects of Al stress (10 mM) and P deficiency (0.05 mM) on the proteome of three aluminum-tolerant phosphobacteria: Enterobacter sp. 198, Enterobacter sp. RJAL6, and Klebsiella sp. RCJ4. Cultivated under varying conditions, P deficiency upregulated P metabolism proteins while Al exposure downregulated iron-sulfur and heme-containing proteins and upregulated iron acquisition proteins. This demonstrated that Al influence on iron homeostasis and bacterial central metabolism. This study offers crucial insights into bacterial behavior in acidic soils, benefiting the development of bioinoculants for crops facing Al toxicity and P deficiency. This investigation marks the first proteomic study on the interaction between high Al and P deficiency in acid soils-adapted bacteria. more...

Soil is a non-renewable resource on a human scale and highly vulnerable to erosion due to anthropogenic management and the variable effects of climate. In Chile, the lack of a legislative concept for soil and changes in Land Use Capacity (LUCap) have constituted the main facilitating agents of soil erosion. Given the inadequacy of current land regulations, and to guide and contribute to the sustainability of the resource, this study presents a proposal for new land use legislation in Chile. We analyse the current national legislation on changes in the LUCap and compare the current land use in the Claro River sub-basin, Chile, with existing LUCap classes, identifying the legal criteria for establishing a national land use regulation, by comparing with international law from Costa Rica and Spain. We carried out a qualitative review analysis of 20 Chilean land use regulations and a quantitative, multi-temporal analysis of LUCap change in the Claro River sub-basin, using spatial analysis tools (ArcGIS 10.1 and/or QGIS 3.14) in Raster and Vector format. Legislations from Costa Rica and Spain were chosen due to similarities with Chilean environmental regulations. We observed that Chile must introduce a Framework Land Law with principles of protection and sustainability for regulating soil. Deforestation was the main land loss driver (60% of native forest loss) in the study area during the 16-year study period, as well as inadequate agricultural management practices. It is essential to unify legislation, following the example of comparative laws of Spain, with the vision of Costa Rica. more...