Recent developments in the application of plant growth-promoting drought adaptive rhizobacteria for drought mitigation

Drought intensity that has increased as a result of human activity and global warming poses a serious danger to agricultural output. The demand for ecologically friendly solutions to ensure the security of the world’s food supply has increased as a result. Plant growth-promoting rhizobacteria (PGPR) treatment may be advantageous in this situation. PGPR guarantees the survival of the plant during a drought through a variety of processes including osmotic adjustments, improved phytohormone synthesis, and antioxidant activity, among others and these mechanisms also promote the plant’s development. In addition, new developments in omics technology have improved our understanding of PGPR, which makes it easier to investigate the genes involved in colonizing plant tissue. Therefore, this review addresses the mechanisms of PGPR in drought stress resistance to summarize the most current omics-based and molecular methodologies for exploring the function of drought-responsive genes. The study discusses a detailed mechanistic approach, PGPR-based bioinoculant design, and a potential roadmap for enhancing their efficacy in combating drought stress

Using Geochemical Fingerprints for Assessing Sediment Source Apportionment in an Agricultural Catchment in Central Argentina

In the hilly semi-arid region of central Argentina, where the agricultural frontier expands at the expense of natural ecosystems, soil erosion is one of the most alarming environmental problems. Thus, obtaining knowledge about the dynamics of erosive processes and identifying erosion hotspots constitutes a primary scientific objective. This investigation is focused on estimating the apportion-ments of main sources of sediments, at the mouth of a small catchment called Durazno del Medio, located in the province of San Luis, Argentina. Elemental Analysis, measured by Energy Dispersive X-ray Fluorescence (EDXRF), was used to select potential geochemical fingerprints of sediment. The unmixing model MixSIAR was applied to approximate the contribution of each identified source in the sediment accumulation areas at the mouth of the catchment. Potential sediment sources were selected using two criteria: (i) a hierarchical approach to identify the main geomorphological units (GUs) and (ii) the main land uses (LU), recognized by examining satellite images and field recogni-tions. The selected geochemical tracers were able to distinguish sources located in the Crystalline basement hills with loess-patched (CBH) as the main sediment contributors.Fil: Garcias Paez, Yanina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Torres Astorga, Romina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Ojeda, Guillermo. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Departamento de Geología; ArgentinaFil: de los Santos Villalobos, Sergio. Instituto Tecnológico de Sonora; MéxicoFil: Tejeda, Samuel. Instituto Nacional de Investigaciones Nucleares; MéxicoFil: Velasco, Ricardo Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentin

Geochemical fingerprints for tracing sediments in the sub-catchment Durazno del Medio, Argentina

Soil erosion is one of the most serious environmental problems caused by land-use changes in semi-arid regions of central Argentina. Hence, to understand the erosive dynamics in these regions becomes fundamental. Sub-catchment Durazno del Medio (6.56 km2) is located 21 km northeast of San Luis City (S 33º 08’ 16” – W 66º 09’ 18”; S 33º 11’ 44” – W 66º 08’ 06”), in the central region of Argentina. The average annual temperature is 17 ºC. Annual rainfall ranges from 600 to 800 mm, with a tendency to increase in the last years. Rainfall varies seasonally, with a dry season from May to October and a rainy season from November to April. This agricultural catchment has been researched to identify critical hot spots of land degradation by applying sediment source fingerprinting techniques. In the studied area, exotic tree plantations in protected areas (in a state of youth development), native woodland, roads (dirt and paved), agricultural fields, and channel banks were identified as sources of sediments. Most of the sources were found on quaternary deposits (loessoid deposits), except native forests and some roads, which were found in gneiss and migmatites. The sub-catchment has a drainage network formed by two water courses that converge into the main one. Channel sediments (mixtures) were collected at the end of the main channel. The energy dispersive X-ray fluorescence (EDXRF) analytical technique and the MixSIAR unmixing model were implemented to estimate the contribution of sediment sources in mixtures. The sources and mixtures (tablets) were analyzed in triplicate using a Si-Li detector SDD (resolution 145 keV, Kalpha Mn) with a X ray tube of 50 W and 50 kV. The tracers were analyzed using a fundamental parameters method. Since the selection of correct fingerprints has been proven to be an essential stage in the analysis, before unmixing the natural sediment samples, two artificial mixtures were made using known quantities of soil collected in the identified sources to test the precision and robustness of the tracers selection procedure. These analyses showed that the use of most of the tracers (25 elements) increases the exactitude of calculated proportions. The first mixture was made using two sources, exotic tree plantation in protected areas (35.6 %) and agricultural fields (64.4 %). The second mixture was created using different proportions of 4 different sources including native woodland (30 %), exotic tree plantation in protected areas (20 %), agricultural fields (5 %) and channel banks (45 %). A low mean absolute error (MAE) of 2 % and 4 %, respectively, was obtained when reconstructing the 2 artificial mixtures. This outcome indicates that the selection process was effective. Once the tracers were properly selected, the natural sediment samples were analyzed. Hence, for the catchment mixture, the main sources of sediments were exotic tree plantation in protected areas (96.7 %) and roads (1.8 %). The application of the fingerprint technique highlighted that forests are one of the largest contributors of sediment, followed by dirt roads.Fil: Garcias Paez, Yanina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Torres Astorga, Romina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Borgatello, Gisela Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Tejeda, Samuel. Instituto Nacional de Investigaciones Nucleares; MéxicoFil: de los Santos Villalobos, Sergio. Instituto Tecnológico de Sonora; MéxicoFil: Velasco, Ricardo Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaEGU General Assembly 2021VienaAustriaEuropean Geosciences Unio

Trichoderma species : our best fungal allies in the biocontrol of plant diseases : a review

Biocontrol agents (BCA) have been an important tool in agriculture to prevent crop losses due to plant pathogens infections and to increase plant food production globally, diminishing the necessity for chemical pesticides and fertilizers and offering a more sustainable and environmentally friendly option. Fungi from the genus Trichoderma are among the most used and studied microorganisms as BCA due to the variety of biocontrol traits, such as parasitism, antibiosis, secondary metabolites (SM) production, and plant defense system induction. Several Trichoderma species are well-known mycoparasites. However, some of those species can antagonize other organisms such as nematodes and plant pests, making this fungus a very versatile BCA. Trichoderma has been used in agriculture as part of innovative bioformulations, either just Trichoderma species or in combination with other plant-beneficial microbes, such as plant growth-promoting bacteria (PGPB). Here, we review the most recent literature regarding the biocontrol studies about six of the most used Trichoderma species, T. atroviride, T. harzianum, T. asperellum, T. virens, T. longibrachiatum, and T. viride, highlighting their biocontrol traits and the use of these fungal genera in Trichoderma-based formulations to control or prevent plant diseases, and their importance as a substitute for chemical pesticides and fertilizers

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity

Beneficial Microorganisms in Sustainable Agriculture: Harnessing Microbes’ Potential to Help Feed the World

The global population is projected to increase to near 10 billion people by the year 2050 [...

Biofouling of FeNP-Coated SWRO Membranes with Bacteria Isolated after Pre-Treatment in the Sea of Cortez

Commercial seawater reverse osmosis (SWRO) membranes were coated with iron nanoparticles (FeNPs) and biofouled with a bacterium strain isolated from the Sea of Cortez, Mexico. This strain was selected and characterized, as it was the only cultivable strain in pretreated seawater. Molecular identification of the strain showed that it belongs to Bacillus halotolerans MCC1. This strain was Gram positive with spore production, and was susceptible to Fe+2 toxicity with a minimum inhibitory concentration of 1.8 g L−1. Its biofouling potential on both uncoated and FeNP coated reverse osmosis (RO) membranes was measured via biofilm layer thickness, total cell count, optical density and organic matter. The FeNP-coated RO membrane presented a significant reduction in biofilm cake layer thickness (>90%), total cells (>67%), optical density (>42%) and organic matter (>92%) with respect to an uncoated commercial membrane. Thus, Bacillus halotolerans MCC1 shows great potential to biofoul RO membranes as it can pass through ultrafiltration membranes due to its spore producing ability; nonetheless, FeNP-coated membranes represent a potential alternative to mitigate RO membrane biofouling