Evaluación de biofertilizantes a base de microorganismos y lixiviado de vermicomposta en cultivos de interés económico en México

Objective: Characterize the effect of a biofertilizer based on vermicompost leachate (VCL) on valuable Mexican crops, formulated in combination with: i) a recommended dose of chemical fertilizer (NPK), ii) a mixture of two commercial products containing plant growth promoting microorganisms and arbuscular mycorrhizal fungi (AMF) and iii) molasses. Design/methodology/approach: Four treatments were evaluated: T1 (VCL, microorganisms, without molasses and without NPK), T2 (VCL, microorganisms, without molasses and with NPK), T3 (only with NPK) and T4 (VCL, microorganisms, molasses and without NPK), distributed in 128 pots where eight species of crops with 4 replicates each were planted (tomato, pepper, sorghum, bean, peas, corn, squash and watermelon) at greenhouse conditions. After 6 weeks of cultivation, the effect of the biofertilizers was quantified according to the parameters of plant height and number of leaves. Analysis of variance (ANOVA) and the Tukey test were used to determine statistical significance. Results: Treatments T1 and T2 presented the best effects in plant growth for most plants. Watermelon showed better response to T3 whereas in corn insignificant effects were observed. Treatment T4 showed a negative influence on the development of all crops, attributed to the incorporation of molasses. Limitations on study/implications: The study was carried out in a short period of time where it was not possible to evaluate fruit production. Findings/conclusions: VCL combined with plant growth promoting bacteria and AMF, have positive effects on growth of tomato, pepper, sorghum, bean, pea and squash; being able to reduce traditional chemical fertilization by 35% without reducing crop yields. Keywords: Arbuscular mycorrhizal fungi, biofertilizers, Eisenia foetida, plant growth promoting microorganisms, vermicompost leachate.Objetivo: Caracterizar el efecto de un biofertilizante a base de lixiviado vermicomposta (VCL) en cultivos de relevancia en México, formulado en combinación con: i) fertilizante químico (NPK), ii) una mezcla de dos productos comerciales con microorganismos promotores del crecimiento de las plantas y hongos micorrízicos arbusculares (HMA) y iii) melaza. Diseño/metodología/aproximación: Cuatro tratamientos fueron evaluados: T1 (VCL, microorganismos, sin melaza y sin NPK), T2 (VCL, microorganismos, sin melaza y con NPK), T3 (únicamente con NPK) y T4 (VCL, microorganismos, melaza y sin NPK), distribuidos en 128 macetas con ocho especies de cultivos (tomate, chile, sorgo, frijol, chícharo, maíz, calabaza y sandía) (4 réplicas por cultivo) bajo condiciones de invernadero. Después de 6 semanas, se midieron la altura de la planta y número de hojas. La significancia estadística se determinó mediante análisis de varianza (ANOVA) y la prueba de Tukey. Resultados: Los Tratamientos T1 y T2 presentaron los mejores efectos en la mayoría de las plantas. La sandía mostró una mejor respuesta a T3 y en maíz no se observaron efectos significativos. T4 mostró una influencia negativa en el desarrollo de todos los cultivos, atribuido a la incorporación de melaza. Limitaciones del estudio/implicaciones: El estudio se llevó a cabo en un corto período de tiempo y no fue posible evaluar la producción de fruto. Hallazgos/conclusiones: El VCL combinado con bacterias promotoras de crecimiento y HMA, tienen efectos positivos en el crecimiento de tomate, chile, sorgo, chícharo y calabaza; pudiendo reducir la fertilización química en un 35% sin disminuir el rendimiento. Palabras Clave: Biofertilizantes, Eisenia foetida, hongos micorrízicos arbusculares, lixiviado de vermicomposta, microorganismos promotores del crecimiento de plantas

Gut microbial composition and functionality of school-age Mexican population with metabolic syndrome and type-2 diabetes mellitus using shotgun metagenomic sequencing

Gut metagenome in pediatric subjects with metabolic syndrome (MetS) and type-2 diabetes mellitus (T2DM) has been poorly studied, despite an alarming worldwide increase in the prevalence and incidence of obesity and MetS within this population. The objective of this study was to characterize the gut microbiome taxonomic composition of Mexican pediatric subjects with MetS and T2DM using shotgun metagenomics and analyze the potential relationship with metabolic changes and proinflammatory effects. Paired-end reads of fecal DNA samples were obtained through the Illumina HiSeq X Platform. Statistical analyses and correlational studies were conducted using gut microbiome data and metadata from all individuals. Gut microbial dysbiosis was observed in MetS and T2DM children compared to healthy subjects, which was characterized by an increase in facultative anaerobes (i.e., enteric and lactic acid bacteria) and a decrease in strict anaerobes (i.e., Erysipelatoclostridium, Shaalia, and Actinomyces genera). This may cause a loss of gut hypoxic environment, increased gut microbial nitrogen metabolism, and higher production of pathogen-associated molecular patterns. These metabolic changes may trigger the activation of proinflammatory activity and impair the host's intermediate metabolism, leading to a possible progression of the characteristic risk factors of MetS and T2DM, such as insulin resistance, dyslipidemia, and an increased abdominal circumference. Furthermore, specific viruses (Jiaodavirus genus and Inoviridae family) showed positive correlations with proinflammatory cytokines involved in these metabolic diseases. This study provides novel evidence for the characterization of MetS and T2DM pediatric subjects in which the whole gut microbial composition has been characterized. Additionally, it describes specific gut microorganisms with functional changes that may influence the onset of relevant health risk factors

Community composition of arbuscular mycorrhizal fungi associated with native plants growing in a petroleum-polluted soil of the Amazon region of Ecuador

Arbuscular mycorrhizal fungi (AMF) are worldwide distributed plant symbionts. However, their occurrence in hydrocarbon-polluted environments is less investigated, although specific communities may be present with possible interest for remediation strategies. Here, we investigated the AMF community composition associated with the roots of diverse plant species naturally recolonizing a weathered crude oil pond in the Amazon region of Ecuador. Next generation 454 GS-Junior sequencing of an 800 bp LSU rRNA gene PCR amplicon was used. PCR amplicons were affiliated to a maximum-likelihood phylogenetic tree computed from 1.5 kb AMF reference sequences. A high throughput phylogenetic annotation approach, using an evolutionary placement algorithm (EPA) allowed the characterization of sequences to the species level. Fifteen species were detected. Acaulospora species were identified as dominant colonizers, with 73% of relative read abundance, Archaeospora (19.6%) and several genera from the Glomeraceae (Rhizophagus, Glomus macrocarpum-like, Sclerocystis, Dominikia and Kamienskia) were also detected. Although, a diverse community belonging to Glomeraceae was revealed, they represented <10% of the relative abundance in the Pond. Seventy five % of the species could not be identified, suggesting possible new species associated with roots of plants under highly hydrocarbon-polluted conditions

Arbuscular Mycorrhizal Fungal Community Composition in Carludovica palmata, Costus scaber and Euterpe precatoria from Weathered Oil Ponds in the Ecuadorian Amazon

Arbuscular mycorrhizal fungi (AMF) are ubiquitous to most natural and anthropized ecosystems, and are often found in polluted environments. However, their occurrence and community composition in highly weathered petroleum-polluted soils has been infrequently reported. In the present study, two ponds of weathered crude oil and their surrounding soil from the Charapa field in the Amazon region of Ecuador were selected and root colonization by AMF of their native plants investigated. The AMF community was further analyzed in three selected plant species (i.e., Carludovica palmata, Costus scaber and Euterpe precatoria) present in the two ponds and the surrounding soil. A fragment covering partial SSU, the whole ITS and partial LSU rDNA region was amplified (i.e., 1.5 kb), cloned and sequenced from the roots of each host species. AMF root colonization exceeded 56% in all plant species examined and no significant difference was observed between sites or plants. For AMF community analysis, a total of 138 AMF sequences were obtained and sorted into 32 OTUs based on clustering (threshold ≥97%) by OPTSIL. The found OTUs belonged to the genera Rhizophagus (22%), Glomus (31%), Acaulospora (25%) and Archaeospora (22%). Glomus and Archaeospora were always present regardless of the plant species or the site. Acaulospora was found in the three plant species and in the two ponds while Rhizophagus was revealed only in the surrounding soil in one plant species (Euterpe precatoria). Our study contributed to the molecular community composition of AMF and revealed an unexpected high presence of four AMF genera which have established a symbiosis with roots of native plants from the Amazon forest under high polluted soil conditions

Arbuscular Mycorrhizal Fungal Community Composition in Carludovica palmata, Costus scaber and Euterpe precatoria from Weathered Oil Ponds in the Ecuadorian Amazon

Arbuscular mycorrhizal fungi (AMF) are ubiquitous to most natural and anthropized ecosystems, and are often found in polluted environments. However, their occurrence and community composition in highly weathered petroleum-polluted soils has been infrequently reported. In the present study, two ponds of weathered crude oil and their surrounding soil from the Charapa field in the Amazon region of Ecuador were selected and root colonization by AMF of their native plants investigated. The AMF community was further analyzed in three selected plant species (i.e., Carludovica palmata, Costus scaber and Euterpe precatoria) present in the two ponds and the surrounding soil. A fragment covering partial SSU, the whole ITS and partial LSU rDNA region was amplified (i.e., 1.5 kb), cloned and sequenced from the roots of each host species. AMF root colonization exceeded 56% in all plant species examined and no significant difference was observed between sites or plants. For AMF community analysis, a total of 138 AMF sequences were obtained and sorted into 32 OTUs based on clustering (threshold ≥97%) by OPTSIL. The found OTUs belonged to the genera Rhizophagus (22%), Glomus (31%), Acaulospora (25%) and Archaeospora (22%). Glomus and Archaeospora were always present regardless of the plant species or the site. Acaulospora was found in the three plant species and in the two ponds while Rhizophagus was revealed only in the surrounding soil in one plant species (Euterpe precatoria). Our study contributed to the molecular community composition of AMF and revealed an unexpected high presence of four AMF genera which have established a symbiosis with roots of native plants from the Amazon forest under high polluted soil conditions

Image_1_Characterizing a subtropical hypereutrophic lake: From physicochemical variables to shotgun metagenomic data.JPEG

Lake Cajititlán is a subtropical and endorheic lake, which is heavily impacted by nutrient pollution. Agricultural runoff and poorly treated wastewater have entered this reservoir at alarming rates during past rainy seasons, causing the cultural eutrophication of this body of water and resulting in several massive fish kill events. In this study, shotgun metagenomic sequencing was used to examine the taxonomic and functional structure of microbial communities in Lake Cajititlán during the rainy season. Several water quality features and their interactions with microbial communities were also assessed to identify the major factors affecting the water quality and biota, specifically fish species. According to current water quality regulations, most of the physicochemical variables analyzed (dissolved oxygen, pH, Secchi disk, NH4+, NO3−, blue-green algae, total phosphorus, and chlorophyll-a) were outside of the permissible limits. Planktothrix agardhii and Microcystis aeruginosa were the most abundant phytoplankton species, and the dominant bacterial genera were Pseudomonas, Streptomyces, and Flavobacterium, with Pseudomonas fluorescens, Stenotrophomonas maltophilia, and Aeromonas veronii representing the most abundant bacterial species. All of these microorganisms have been reported to be potentially harmful to fish, and the latter three (P. fluorescens, S. maltophilia, A. veronii) also contain genes associated with pathogenicity in fish mortality (fur, luxS, aer, act, aha, exu, lip, ser). Genetic evidence from the microbial communities analyzed herein reveals that anthropogenic sources of nutrients in the lake altered genes involved in nitrogen, phosphorus, sulfur, and carbon metabolism, mainly at the beginning of the rainy season. These findings suggest that abiotic factors influence the structure of the microbial communities, along with the major biogeochemical cycles of Lake Cajititlán, resulting in temporal variations and an excess of microorganisms that can thrive in high-nutrient and low-oxygen environments. After reviewing the literature, this appears to be the first study that focuses on characterizing the water quality of a subtropical hypereutrophic lake through associations between physicochemical variables and shotgun metagenomic data. In addition, there are few studies that have coupled the metabolism of aquatic ecosystems with nutrient cycles.</p

Chemical Genetics Applied to Elucidate the Physiological Role of Stress-Signaling Molecules on the Wound-Induced Accumulation of Glucosinolates in Broccoli

Wounding stress is an effective strategy to induce glucosinolate (GS) biosynthesis in broccoli. However, there is insufficient knowledge on the physiological and molecular mechanisms underlying this stress response. Herein, a chemical-genetic approach was applied to elucidate the role of jasmonic acid (JA), ethylene (ET), and reactive oxygen species (ROS) on the wound-induced biosynthesis of GS. Broccoli was processed into chops to induce wounding stress. Broccoli chops were treated with phenidone (PHEN) and diphenyleneiodonium chloride (DPI) as inhibitors of JA and ROS biosynthesis, respectively, whereas 1-methylcyclopropene (1-MCP) was applied as an inhibitor of ET action. Wounding stress induced the expression of genes related to the biosynthesis of indolic and aliphatic GS, which was correlated with the accumulation of GS and modulated by the inhibitors of signaling molecules applied. Results of gene expression analysis indicated that JA played a key role in the activation of most genes, followed by ROS. Furthermore, except for the CYP79B2 gene, PHEN and 1-MCP synergistically downregulated the expression of GS biosynthetic genes evaluated, showing that the interaction between JA and ET was fundamental to modulate GS biosynthesis. Results presented herein increased our knowledge of the physiological and molecular mechanisms governing the wound-induced biosynthesis of GS in broccoli

Cross-Talk and Physiological Role of Jasmonic Acid, Ethylene, and Reactive Oxygen Species in Wound-Induced Phenolic Biosynthesis in Broccoli

Wounding induces phenolic biosynthesis in broccoli. However, there is scarce information about the physiological and molecular mechanisms governing this stress response. In the present study, a chemical-genetics approach was used to elucidate the role of reactive oxygen species (ROS), jasmonic acid (JA), and ethylene (ET) as stress-signaling molecules in the wound-induced phenolic biosynthesis in broccoli. Wounding activated the biosynthesis of ET and JA. Likewise, the wound-induced biosynthesis of ET and JA was regulated by ROS. JA activated primary metabolism, whereas the three signaling molecules activated phenylpropanoid metabolism. The signaling molecules inhibited the wound-induced activation of the hydroxycinnamoyl-CoA quinate hydroxycinnamoyl transferase (HQT) gene, which is involved in caffeoylquinic acids biosynthesis, and the main phenolics accumulated in wounded broccoli, suggesting that an alternative caffeoylquinic biosynthesis pathway is activated in the tissue due to wounding. ROS mediated the biosynthesis of most individual phenolic compounds evaluated. In conclusion, ROS, ET, and JA are essential in activating broccoli’s primary and secondary metabolism, resulting in phenolic accumulation