Los nematodos entomopatógenos (NEP) son organismos que habitan en el suelo y que se han utilizado como agentes de control biológico de insectos en las últimas cuatro décadas . Estos organismos han ganado mucha atención debido a su capacidad para buscar y matar a su huésped. El único estadio capaz de matar insectos es el llamado juvenil infectivo (IJ). Una vez que los IJ han ingresado al hospedador, se libera un simbionte bacteriano y la muerte ocurre por septicemia entre las 48 a 96h. Los NEP son seguros para los organismos no-diana, amigables con el ambiente y pueden producirse en masa en grandes fermentadores. A pesar de todas las ventajas mencionadas, en ocasiones, el performance de estos nematodos no es tan bueno como se espera. Uno de los principales problemas relacionados con dichas fallas es la existencia de grandes vacíos en su caracterización biológica y ecológica. Por ejemplo, la distribución de NEP en el suelo (como una matriz tridimensional) después de su aplicación en el campo no se conoce totalmente porque la determinación de su presencia depende de pruebas indirectas usando insectos trampas. Otra opción es el uso de RT-PCR para correlacionar la cantidad de ADN de una especie de NEP con una cantidad de individuos en una muestra de suelo, requiriendo mucho tiempo y esfuerzo. Aún existen muchas preguntas que resolver, incluida la distribución y persistencia en el suelo de los NEO, y la competencia entre las “poblaciones naturales” y las “aplicadas comercialmente”, que siguen sin respuesta debido a la complejidad de la matriz del suelo.
La opción más precisa para comprender cómo se comportan los NEP en el suelo sería, marcarlos individualmente y en grandes cantidades para rastrearlas en tiempo real. El marcaje NEP nos permitirá extraerlos directamente del suelo y contarlos bajo cualquier diseño óptico. Desafortunadamente, el único método disponible para marcar nematodos hasta el momento se basa en la inserción de proteínas fluorescentes, que son costosas, consumen mucho tiempo e imposibles de aplicar a grandes lotes de nematodos (decenas de millones). Esta situación puede ser revertida con el uso de puntos cuánticos de carbono (C-dots),ya que son baratos de producir, fluorescentes, no tóxicos y listos para usar en grandes lotes de NEP. El objetivo de este proyecto es desarrollar tecnologías de marcaje de NEP con c-dots para poder mejorar su actividad en condiciones de campo.

Proyecto de colaboración internacional entre España, Chile, Argentina y Ecuador. El proyecto aborda la recuperación de suelos degradados a través del uso de enmiendas orgánicas.

Microplastics (MPs) are plastic particles that range in size from 0.1 μm to 5 mm. They have received widespread attention in the global environmental science community due to their potential effects on living organisms, ecosystem pollution, low recycling rate, and interaction with organic and inorganic contaminants. Although much research has been focused on MPs in aquatic ecosystems, terrestrial ecosystems have been largely overlooked. Consequently, there is still scarce knowledge on the sources and occurrence of MPs in soils. After being deposited in soil, MPs undergo an aging process that involves the breakdown of their polymeric chains, which promotes the interaction between MPs and organic and inorganic contaminants. This process further increases the toxicity of MPs when they sorb pollutants from the environment, which can be transported to water bodies and living organisms. However, research regarding the aging of MPs and their toxicity is needed since previous studies do not consider realistic soil conditions. Additionally, interactions between MPs and pollutants have been primarily studied for conventional MPs, with scarce research on such topics for degradable MPs, especially concerning interactions with metal(loid)s. In general, the interaction of degradable MPs with other contaminants and their further toxicity have been overlooked.

MPs have been shown to negatively affect some physical, chemical, and biological soil properties. However, results varied between studies, which have been associated with the type and shape of MPs, soil aggregate structure, porosity, water and oxygen availability, among others. More research is needed to confirm such relationships in soils. Previous studies have been mainly performed in Europe and Asia, with scarce research in Latin America. In Chile, only one study has been conducted on MPs in soils at field conditions, with other two studies regarding the effect of MPs and metals on soil biochemical properties under controlled environments. Therefore, considerable efforts should be taken to study MPs in Chilean soils. Thus, this study aims to address these gaps by considering some realistic approaches that are missing from current research on MPs. Specifically, this research will: 1) assess MPs in soils from different land uses and examine their association with soil properties; 2) evaluate degradable MPs; 3) study the ageing and adsorption capability of different MPs to metal(loid)s in soils; and 4) investigate the interactive effect of MPs and metal(loid)s under realistic conditions (including a real dose of MPs and metal(loid)s, temperature fluctuations, and soils from different land use types). By taking these steps, this study will provide novel insights into the occurrence of MPs in Chilean soils and shed light on the dynamics of soil microbial communities in the presence of MPs and metal(loid)s.

Based on the above, the proposed research aims to evaluate the effect of different types of MPs and their interaction with metal(loid)s on the soil community structure and functionality from different land use types under realistic conditions. The hypothesis is that MPs will negatively affect soil microbiome structure and functionality due to changes in soil physicochemical properties, which will be moderated by changes in the type, doses, ageing of MPs and their interactions with metal(loid)s in soil from different land type uses. This proposal will be conducted in the O’Higgins Region (VI) of Chile. Firstly, in Phase 1, six localities from different land use types will be selected: an urban wetland, agricultural field, and sclerophyll forest. Soil samples will be taken to quantify and characterize the types of MPs in soil. Secondly, in Phase 2, the evaluation of different types of aging of MPs (conventional and degradable) on chemical characteristics of such particles will be performed, which is based on the ability of MPs as carriers of metal(loid)s. With information and soils obtained from Phase 1, a realistic experimental approach will be performed in the Phase 3. These include the evaluation of aged MPs (degradable and non-degradable) on soil physicochemical and biochemical properties, and the study of degradable and non-degradable aged MPs with metal(loid)s on the functionality, structure, and co-occurrence patterns of soil microbial communities. These phases are designed to be performed over three years. This is the first study focused on the evaluation the effect of MPs and metal(loid)s on microbial communities of soils from different land use types in Chile.

Promover una alianza nacional e internacional con el fin de fortalecer la red de colaboración en el sistema suelo–planta para la generación sustentable e inocua de alimentos, mediante la aplicación de estrategias biotecnológicas y académicas, con foco en el cambio climático y prevención de contaminantes emergentes, como las micotoxinas.

Mining activities have discharged large amounts of wastes or mine tailings to the environment, which represent an important environmental issue. Mine tailings are mainly characterised by poor physicochemical properties that limit the plant establishment and development. The most negative property in these mine wastes is the high content of metals and metalloids [metal(loid)s], which are often highly toxic due to acid pH that increases metal(loid) bioavailability. This negatively affects living organisms and ecological functioning since soil microorganisms are pioneer colonisers that mediate the plant establishment. Also, mine tailings are usually deposited in abandoned locations of large land cover; from where, due to their physical characteristics, they can be transported by air and water, affecting communities and the environment in surrounding areas. There are several industrial strategies focused on the physical and chemical management of mine tailings, but these are highly expensive and occasionally not effective. These strategies have not been suitable techniques to reduce negative impacts of mine tailings on the environment. In this context, biological approaches, such as phytoremediation, have been proposed as more appropriate strategies due to low cost, easy applicability, and promising results. Nevertheless, most of the studies focused on phytoremediation of mine tailings, especially Chilean studies, have been performed in laboratory conditions. Although these studies show promising conclusions, in many cases unsuccessful results are obtained at field conditions, mainly due to laboratory experiments do not consider the dynamic field variability and potential ecological interactions.
Based on the above, the proposed research aims to evaluate the effect of the initial addition of organic-mineral amendments and the bioaugmentation of microbial communities with “core microbiome” from the root-zone of native herbaceous on the growth and development of native plants and microbial communities at copper mine tailings. We hypothesise that the growth and development of native plants in mine tailings will be promoted by the improvement of physicochemical properties of modified mine tailings (incipient technosols) through the addition of organic-mineral amendments, and the bioaugmentation of microbial communities with “core microbiome” involved in plant fitness obtained from copper mine tailings and surrounding soils.
To evaluate the mentioned hypothesis, this study will be executed in three phases: 1) Initial field characterisation: this will be done for mine tailings and soils under sclerophyllous forest; 2) Collection and recruitment of “core microbiome”: this will study the composition, function, and interactions of “core microbiome” obtained from the root-zone of native herbaceous established on mine tailings and soils under sclerophyllous forest, by which a laboratory-scale assay it is needed to produce inoculum of such ecological units (cores); 3) Restoration field experiment: this consists on the field establishment of native herbaceous species by bioaugmentation with “core microbiome” from root-zone mine tailings and root-zone soil on incipient technosols produced by the addition of organic-mineral amendments on mine tailings. These phases are designed to be performed in three years.
This study can provide insights of the promotion of ecological process and natural resilience on microbial communities of mine tailings and surroundings, which can allow the initial plant establishment a development for later possible plant recruitment from the native sclerophyllous forest. This would also evaluate whether mine tailings can be in situ managed instead of been totally removed, which implies high costs and workflow to enterprises. Additionally, this study would represent the first approach of the evaluation of the biological functioning and composition of microbial communities from root-zone mine tailings in Chile, from its current state to the subsequent restoration process.

Sistema Articulado de Investigación en Cambio Climático y Sustentabilidad de Zonas Costeras de Chile CUECH/RISUE RED21992