Biochemical responses of Echinochloa polystachya inoculated with a Trichoderma consortium during the removal of a pyrethroid-based pesticide.

The biochemical response of plants exposed to pesticides and inoculated with microorganisms is of great importance to explore cleaning up strategies for contaminated sites with pyrethroid-based pesticides. We evaluated the effects of a Trichoderma consortium on the biochemical responses of Echinochloa polystachya plants during the removal of a pyrethroid-based pesticide. Plants were inoculated or not with the Trichoderma consortium and exposed to commercial pesticide H24®, based on pyrethroids. Pesticide application resulted in significant reduction in root protein content (58%), but enhanced content of malondialdehyde (MDA) in shoots, superoxide dismutase (SOD) activity in shoots and roots, and catalase (CAT) activity in roots. Inoculation of Trichoderma consortium in E. polystachya exposed to the pesticide resulted in increased protein content in roots and MDA content in shoots (2-fold). Trichoderma consortium improved protein content and SOD activity (140-fold) in plants. Fungal inoculation increased the removal (97.9%) of the pesticide in comparison to the sole effect of plants (33.9%). Results allow further understanding about the responses of the interaction between plants and root-associated fungi to improving the assisted-phytoremediation of solid matrices contaminated with organic pesticides.

This original paper describes the positive role of the Trichoderma sp. consortium on favoring the removal of a pyretrhoid-based pesticide. This is one of first reports on analyzing the influence of a Trichoderma consortium on the oxidative stress and antioxidant response of Echinochloa polystachya in presence of the pesticide. This experimental approach provides a new alternative for further fungal assisted-phytoremediation of a pyretrhoid-based pesticide.

Growth, tolerance, and enzyme activities of Trichoderma strains in culture media added with a pyrethroids-based insecticide.

The application of pyrethroids and carbamates represents an environmental risk and may exert adverse effects on beneficial microorganisms such as Trichoderma, which contribute to the biocontrol of several fungal phytopathogens. This research evaluated the tolerance of several strains of Trichoderma to a selected culture medium contaminated with a commercial insecticide (H24®) composed of pyrethroids, permethrin and prallethrin, and carbamate propoxur, and determined the influence of this insecticide on the release of enzymes such as chitinases, peroxidases, and endoglucanases by a consortium of selected Trichoderma strains grown in liquid culture medium. Four out of 10 Trichoderma strains showed tolerance to 200ppm (∼48.3% of growth) of the commercial insecticide after 96h of exposure to a contaminated solid medium. After eight days of growth in liquid culture, the insecticide enhanced extracellular protein content and peroxidase activities in the Trichoderma consortium but decreased both chitinase and glucanase activities. These fungal responses should be considered when implementing strategies that combine alternative pesticides and fungal biocontrollers for managing fungal phytopathogens.

Cellulase and chitinase activities and antagonism against Fusarium oxysporum f.sp. cubense race 1 of six Trichoderma strains isolated from Mexican maize cropping.

OBJECTIVE: To evaluate the enzymatic and biocontrol capacity of native Trichoderma strains isolated from corn crops in Irapuato (state of Guanajuato) and Napízaro (state of Michoacán), Mexico. RESULTS: Six native strains from Irapuato and Napízaro were tested, with five of them identified as T. harzianum and one as T. tomentosum. The six strains qualitatively and quantitatively showed enzyme activity for cellulase and chitinase. The best results were obtained for strains IrV6SIC7 and MichV6S2C2 with 878 IU L-1 of chitinase and 1323 IU L-1 of cellulase, respectively. All Trichoderma strains acted antagonistically toward Fusarium oxysporum f.sp. cubense race 1 (FocR1), with percentages of inhibition that ranged from 9 to 54%. In addition, the microscopic analysis allowed visualizing the mechanisms of mycoparasitism and antibiosis by either IrV6SIC7 or MichV6S2C2. The latter effects indicate that the tested native Trichoderma strains isolated from corn crops possessed enzymatic mechanisms as a strategy for biocontrolling FocR1 strains. CONCLUSION: The enzyme production by the Trichoderma strains represents a potential biotechnological utilization for either agricultural or industrial purposes.

Phytoremediation of soil contaminated with weathered petroleum hydrocarbons by applying mineral fertilization, an anionic surfactant, or hydrocarbonoclastic bacteria.

This study evaluated the effect of the application of mineral fertilization (F), the anionic surfactant Triton X-100 (TX100), or the inoculation with a hydrocarbooclastic bacterial consortium (BCons) on the growth of Clitoria ternatea during the phytoremediation of a Gleysol contaminated with weathered petroleum hydrocarbons (39,000 mg kg-1 WPH) collected from La Venta, Tabasco (Mexico). The experiment consisted of a completely randomized design with seven treatments and four replications each under greenhouse conditions. The application of F (biostimulation) increased plant growth and biomass production; in contrast, TX100 only favored root biomass (11%) but significantly favored WPH degradation. Bioaugmentation with BCons did not show significant effects on plant growth. Nevertheless, the combination of biostimulation with bioaugmentation (BCons + F, BCons + TX100, and BCons + F+TX100) enhanced plant growth, hydrocarbonoclastic bacteria population, and WPH degradation when compared to treatments with the single application of bioaugmentation (BCons) or biostimulation (F).

Application of mineral fertilization and commercial surfactant favored root biomass and degradation of weathered petroleum hydrocarbons (WPH). The reintroduction of hydrocarbonoclastic and surfactant-producer bacteria did not enhance plant growth but significantly contributed on WPH degradation from a chronically contaminated soil.

Short-Term Evaluation of the Spatial Distribution of Trophic Groups of Amoebae in the Rhizosphere of Zea mays Inoculated with Rhizophagus intraradices.

Primary production in terrestrial ecosystems is sustained by plants, microbiota, and fungi, which are the major organic matter providers in the root zone, setting in motion the soil food webs. Predators like soil amoebae voraciously feed on bacteria, fungi, and microbial eukaryotes releasing the nutrients sequestered in their biomass. Early food web setting up is crucial for seedling nutrition and its further development after establishment. Mycorrhizal fungi are more than phosphorus providers, and we wonder what their role is in structuring the predators' trophic groups in the root zone. We evaluated the effect of Rhizophagus intraradices inoculated in Zea mays (mycorrhizosphere), on the structuration of amoebae trophic groups along vertical and horizontal (3, 6, and 9 cm) soil distribution when compared to un-inoculated plants, after 20 days in microcosms. Amoebae species richness was highest in non-mycorrhizal seedlings in the root zone at 6- to 9-cm depth, and 3 cm away from plants. More bacterial species are needed when plants are devoid of mycorrhiza, and their influence is constrained 3 cm away from roots. Higher diversity of trophic groups was recorded at mycorrhizal seedlings and at the compartment influenced by the mycelium at 6- to 9-cm depth. The highest bacterivorous diversity, higher number of rare species and protozoa-eating amoebae, and the absence of fungivorous group recorded at the mycorrhizosphere of Z. mays, indicate that the community was very different from the non-mycorrhizal plants. We conclude that the arbuscular mycorrhizal fungus exerts significant changes on the community of trophic groups of amoebae.

Nesting substrates and nest density of stingless bees in the Petenes Biosphere Reserve, Mexico / Sustratos de nidificación y densidad de nidos de abejas sin aguijón en la reserva de la biósfera de los petenes, méxico

RESUMEN Las abejas sin aguijón (ASA) son organismos relevantes en los ecosistemas por su desempeño como polinizadores. En México, la mayor diversidad de ASA se encuentra en el sureste. En este estudio se determinaron las especies de ASA y densidad de nidos en dos sitios con diferente perturbación dentro de la Reserva de la Biósfera de los Petenes (RBLP) Campeche (México). Asimismo, se identificaron los sustratos y las especies arbóreas de nidificación. En total se realizaron diez muestreos en transectos entre los meses de enero a mayo de 2018. Se registraron 56 nidos pertenecientes a ocho especies diferentes de ASA (Cephalotrigona zexmeniae, Frieseomelitta nigra, Lestrimellita niitkib, Nannotrigona perilampoides, Partamona bilineata, Plebeia frontalis, Scaptotrigona pectoralis y Trígona fulviventris). Las especies con mayor número de nidos correspondieron a F. nigra (41,07 %) y S. pectoralis (28,57 %). No se encontraron diferencias significativas en la densidad de nidos entre los sitios Hecelchakán (2,15 nidos/ha) y Calkiní (0,19 nidos/ha). El sustrato preferido para anidación son las cavidades en árboles vivos (78,57 %). En total 15 especies arbóreas fueron identificadas como sustrato de nidificación y la especie más abundante correspondió a Crescentia cujete (n = 18, 40,9 %). El grado de perturbación tuvo poco efecto en el número y densidad de nidos de ASA, sin embargo, en general, la RBLP presentó una composición de especies y densidad de nidos reducida. Por lo tanto, este estudio permitió establecer las bases para futuros estudios sobre estrategias de manejo y conservación de estas especies para evitar su desaparición en la RBLP.

ABSTRACT Stingless bees (ASA) are relevant organisms in ecosystems because of their performance as pollinators. In Mexico, the higher diversity of ASA is found in the southeast. In this study, the ASA species and nest density of nests were identified at two sites with different disturbances (Hecelchakán and Calkiní) within the Petenes Biosphere Reserve (RBLP), Campeche (Mexico). Also, the substrates and the nesting tree species were identified. In total, ten sampling transects were performed between January and May 2018. In total 56 nests belonging to eight different species of ASA (Cephalotrigonazexmeniae, Frieseomelitta nigra, Lestrimellita niitkib, Nanotrigonaperilampoides, Partamona bilineata, Plebeia frontalis, Scaptotrigona pectoralis and Trigona fulviventris) were found. The species with the highest number of nests corresponded to F. nigra (41.07 %) and S. pectoralis (28.57 %). No significant differences were found in nest density between the Hecelchakán (2.15 nests/ha) and Calkiní (0.19 nests/ha) site. The preferred substrate for nesting is cavities in living trees (78.57 %). In total 15 tree species were identified as nesting substrate and the most abundant species corresponded to Crescentia cujete (n = 8, 40.90 %). The degree of disturbance had little effect on the number and density of ASA nest, however, in general, the RBLP presented low species composition and nest density. Therefore, this study allowed to establish the bases for future studies on management and conservation strategies of these species to avoid their loss in the RBLP.

Efecto de bacterias emulsificantes en la atenuación de la fitotoxicidad de suelos contaminados con petróleo intemperizado / Effect of emulsifying bacteria on phytotoxicity attenuation of soils contaminated with weathered petroleum hydrocarbons

Introducción: Las plantas y los microorganismos se han utilizado como bioindicadores de la toxicidad inducida por hidrocarburos presentes en los suelos. Objetivo: El presente trabajo evaluó la toxicidad de un Gleysol contaminado de origen con diferentes concentraciones de petróleo intemperizado, recolectado en la Venta Tabasco (México), en el crecimiento de Clitoria ternatea, y la atenuación de la fitotoxicidad con la inoculación de bacterias emulsificantes. Metodología: Se usaron suelos con 50 y 150 g HTPI kg-1, y un suelo testigo con 0.15 g HTPI kg-1 (origen biogénico), y la inoculación de seis bacterias emulsificantes y su combinación (consorcio). La fitotoxicidad de los HTPI se evaluó considerando la altura, la biomasa seca (radical, aérea y total), el área foliar, el área foliar específica, y la eficiencia del fotosistema II (EPSII), a los 30 días. Resultados: Los HTPI no afectaron la altura, pero el suelo con 50 g HTPI kg-1 redujo la biomasa seca radical y total, y el área foliar con respecto a las plantas en los suelos testigo y con 150 g HTPI kg-1. La cepa Sml (Stenotrophomonas maltophilia C10S1) incrementó significativamente la biomasa seca total; la cepa Ro (Raoultella ornithinolyticaC5S3) produjo mayor área foliar específica con respecto a plantas no inoculadas. En el suelo testigo, el consorcio bacteriano estimuló la altura; las cepas Sm (Serratia marcescens C11S1) y Sm2 (S. marcescens C7S3) mejoraron la altura y el área foliar específica con respecto a plantas no inoculadas, en el suelo con 50 g HTPI kg-1. En el suelo con 150 g HTPI kg-1, las cepas Spa (Stenotrophomonas pavanii C5S3F) y Cfr (Citrobacter freundii C4S3) incrementaron la biomasa seca radical y aérea, respectivamente. La EPSII no fue afectada por la contaminación de los suelos. Las bacterias emulsificantes redujeron la fitotoxicidad de HTPI, pero dependiendo de su contenido en los suelos. Conclusiones: El suelo con 50 g HTPI kg-1 mostró mayor toxicidad en el crecimiento de las plantas. La inoculación bacteriana favoreció el crecimiento, producción de biomasa, y área foliar en el suelo con 150 g HTPI kg-1. La EPSII no fue afectada por la presencia de HTPI en el suelo.

Introduction: Plants and microorganisms have been used as bioindicators to evaluate the toxicity of hydrocarbons in soils. Objective: This study evaluates the toxicity of a chronically-contaminated Gleysol with several concentrations of weathered petroleum hydrocarbons (WPH), collected from La Venta, Tabasco (Mexico), on the growth of Clitoria ternatea and the phytoxicity attenuation due to inoculation of emulsifying bacteria. Methods: Soils with 50 and 150 g WPH kg-1, and control soil with 0.15 g WPH kg-1 (biogenic origin) were utilized, as well as the inoculation of six emulsifying bacteria and their combination (consortium). The WPH-phytotoxicity was evaluated by considering plant height, dry biomass production (root, shoot, and total), leaf area, specific leaf area, and the efficiency of photosystem II (EPSII), after 30 days. Results: WPH did not affect plant height, but soil with 50 g WPH kg-1 diminished root and total dry weight, and leaf area, when compared to both control soil and soil with 150 g WPH kg-1. The strain Sml (Stenotrophomonas maltophilia C10S1) significantly increased shoot and total dry weight, while the strain Ro (Raoultella ornithinolytica C5S3) produced higher specific leaf area relative to uninoculated plants. In control soil, the bacterial consortium stimulated plant height. The strains Sm (Serratia marcescens C11S1)and Sm2 (S. marcescens C7S3) improved plant height and specific leaf area when compared to uninoculated plants in soil with 50 g WPH kg-1. In soil with 150 g WPH kg-1, strains Spa (Stenotrophomonas pavanii C5S3F)and Cfr (Citrobacter freundii C4S3)enhanced root and shoot dry weight, respectively. The EPSII was unaffected by soil contamination. Emulsifying bacteria reduced the phytotoxic effects of WP, but depending on the content of WPH in soils. Conclusions: Soil with 50 g WPH kg-1 showed the greatest phytotoxic effects on plant growth. Bacterial inoculation favored growth, biomass production and leaf area in soil with 150 g WPH kg-1. The EPSII was not affected by WPH in soils.

IMPACT OF CRUDE OIL ON FUNCTIONAL GROUPS OF CULTURABLE BACTERIA AND COLONIZATION OF SYMBIOTIC MICROORGANISMS IN THE Clitoria-Brachiaria RHIZOSPHERE GROWN IN MESOCOSMS / Impacto del petróleo crudo sobre grupos funcionales de bacterias cultivables y colonización de microorganismos simbióticos en la rizosfera de Clitoria-Brachiaria crecidas en mesocosmos

ABSTRACT This research evaluated the changes on populations of culturable N-fixing free bacteria (NFFB) and P-solubilizing bacteria (PSB), as well as on the root nodulation by native rhizobia, the root colonization and spore number of arbuscular mycorrhizal fungi (AMF), in the rhizosphere of Clitoria ternatea and Brachiaria brizantha grown in mesocosms contaminated with crude oil (0, 3000, 6000, 9000, and 12000 mg kg-1), for 240 days. After 24 h of soil contamination, the highest populations of NFFB and PSB (5.5 and 4.9 LogUFC, respectively) were found in control, and the lowest populations were obtained at 12000 mg kg-1 (5.1 and 4.2 LogUFC, respectively). In contrast, at 60 and 240 days, the control showed lower populations of NFFB and PSB (5.4 and 4.8 LogUFC, respectively) than contaminated treatments. The highest number of root nodules in C. ternatea was quantified in control at 60 and 240 days (25 and 27 nodules, respectively) in comparison to those observed at the treatment with 12000 mg kg-1 (7 and 1 nodule, respectively). At 60 days, AMF colonization in both plant species, and the number of spores significantly decreased as the crude oil concentration increased; however, at 240 days, the highest number of AMF spores was recorded at treatments with 6000 and 12000 mg kg-1. The dry weight of both plant species significantly decreased as crude oil concentrations increased. Although C. ternatea was more susceptible to the toxic effects of crude oil, this plant species showed greater content of total chlorophyll than B. brizantha.

RESUMEN Esta investigación evaluó los cambios en la población cultivable de bacterias de vida libre fijadoras de nitrógeno (BVLFN) y de bacterias solubilizadoras de fósforo (BSP), así como en la nodulación de raíces por rizobios nativos, y en la colonización y número de esporas de hongos micorrízicos arbusculares (HMA) en la rizósfera de Clitoria ternatea y Brachiaria brizantha cultivadas en mesocosmos contaminados con petróleo crudo (0, 3000, 6000, 9000 y 12000 mg kg-1), durante 240 días. A las 24 h de la contaminación del suelo, las poblaciones más altas de BVLFN y BSP (5,5 y 4,9 LogUFC, respectivamente) se encontraron en el control, mientras que las poblaciones más bajas se obtuvieron a 12000 mg kg-1 (5,1 y 4,2 LogUFC, respectivamente). En contraste, a los 60 y 240 días, el control mostró bajas poblaciones de BVLFN y BSP (5,4 y 4,8 LogUFC, respectivamente) que los tratamientos contaminados. El mayor número de nódulos en raíz de C. ternatea se cuantificó en el control a los 60 y 240 días (25 y 27 nódulos, respectivamente) en comparación con el tratamiento con 12000 mg kg-1 (7 y 1 nódulos, respectivamente). A los 60 días, la colonización de HMA en ambas especies vegetales y el número de esporas disminuyeron significativamente al aumentar la concentración de petróleo crudo; sin embargo, a los 240 días, se registró el mayor número de esporas de HMA en los tratamientos con 6000 y 12000 mg kg-1. El peso seco vegetal disminuyó significativamente al aumentar las concentraciones de petróleo crudo. Clitoria ternatea fue más susceptible a la toxicidad del petróleo, aunque esta especie vegetal mostró mayor contenido de clorofila total que B. brizantha.

[Responses of the common bean (Phaseolus vulgaris L.) and Rhizobium tropici CIAT899 symbiosystem to induced allelopathy by Ipomoea purpurea L. Roth]. / Respuesta del simbiosistema frijol (Phaseolus vulgaris L.) y Rhizobium tropici CIAT899 ante el efecto alelopático de Ipomoea purpurea L. Roth.

Allelopathy is a phenomenon that involves the production of secondary metabolites that influence the growth of plants and microorganisms; however, this alellopathic effect has been scarcely studied on the rhizobia-legume symbiosis. The aims of this research were 1) to assess the allelopathic potential of aqueous extracts of Ipomoea purpurea L. Roth on seed germination and root length of common bean seedlings (Phaseolus vulgaris L.), 2) to determine its effects on the in vitro growth of Rhizobium tropici CIAT899, and 3) to evaluate the allelopathic potential of I. purpurea on the growth, nodulation and physiology of common bean plants inoculated with R. tropici. After 48h, 15% of the aqueous root extract of I. purpurea stimulated seed germination, whereas 4% of the aqueous shoot extracts stimulated such germination. Both the root or shoot extracts stimulated seed germination and e root length. In vitro growth of R. tropici was inhibited as a result of the application of both aqueous extracts. The presence of I. purpurea negatively affected both the growth and physiological responses of common bean plants, and this effect was attenuated after the inoculation of R. tropici; nevertheless, this allelopathic plant affected root nodulation. Our results suggest that the symbiosis of rhizobia and roots of common bean plants is an important element for attenuating the negative effects caused by the allelopathic plant.

Towards the micropropagation of Euphorbia cyathophora Murray: a wild plant species with medicinal and ornamental potential / Micropropagação de Euphorbia cyathophora Murray: uma especie de planta selvagem com potencial medicinal e ornamental

ABSTRACT: Euphorbia cyathophora Murray is a plant species with medicinal and ornamental potential but whose in vitro propagation is unknown. Two experiments were performed to know 1) the effect of light (WL) at 25±2 °C and 20 μmol m-2 s-1 luminous intensity, or darkness at 20±2 °C, for the first 20 days and subsequent placement in light (DKL) as previously described, and 2) the best combination of plant growth regulators: benzyl amino purine (BAP), kynetin (KIN), 2-isopentenyl adenine (2iP) and thidiazuron (TDZ) in combination with naphthaleneacetic acid (NAA) and the effect of both light conditions. The DKL treatment did not promote the growth of leaves, cotyledons, or plantlet height; in contrast, WL produced a more developed root system with early appearance of tertiary roots. In regards to the interaction of plant regulators and light effect, only the treatment with 1 mg BAP L-1 and 0.1 mg NAA L-1 generated shoots in both light conditions (DKL and WL). Darkness (DKL) generated more indirect greatest morphogenic responses (callus formation).

RESUMO: Euphorbia cyathophora Murray é uma espécie vegetal com potencial medicinal e ornamental, mas cuja propagação in vitro é desconhecida. Dois experimentos foram realizados para conhecer 1) o efeito da luz (WL) a 25±2 °C e 20 μmol m-2 s-1 intensidade luminosa, ou escuridão a 20±2 °C, nos primeiros 20 dias e posterior colocação em luz (DKL) como descrito anteriormente, e 2) a melhor combinação de reguladores de crescimento vegetal: benzil amina purina (BAP), kynetina (KIN), 2-isopentenil adenina (2iP) e thidiazuron (TDZ) em combinação com ácido naftalenoacético (ANA) e o efeito de ambas as condições de luz. O tratamento com DKL não promoveu o crescimento de folhas, cotilédones ou altura das plântulas. Em contraste, a WL produziu um sistema radicular mais desenvolvido com o aparecimento precoce de raízes terciárias. Com relação à interação dos reguladores vegetais e efeito luminoso, apenas o tratamento com 1 mg de BAP L-1 e 0,1 mg de NAA L-1 gerou brotações em ambas as condições de luz (DKL e WL). Escuridão (DKL) gerou mais respostas morfogênicas mais diretas (formação de calo).

Induced accumulation of Au, Ag and Cu in Brassica napus grown in a mine tailings with the inoculation of Aspergillus niger and the application of two chemical compounds.

This study evaluated the ability of Brassica napus for extracting gold (Au), silver (Ag) and copper (Cu) from a mine tailings, with the inoculation of two Aspergillus niger strains, and the application of ammonium thiocyanate (NH4SCN) or ammonium thiosulfate [(NH4)2S2O3]. After seven weeks of growth inoculated or non-inoculated plants were applied with 1 or 2 g kg-1 of either NH4SCN or (NH4)2S2O3, respectively. Eight days after the application of the chemical compounds, plants were harvested for determining the total dry biomass, and the content of Au, Ag, and Cu in plant organs. Application of (NH4)2S2O3 or NH4SCN resulted in enhanced Au-accumulation in stems (447% and 507%, respectively), while either (NH4)2S2O3+Aspergillus, or NH4SCN increased the Au-accumulation in roots (198.5% and 404%, respectively) when compared to the control. Treatments with (NH4)2S2O3 or (NH4)2S2O3+Aspergillus significantly increased (P ≤ 0.001) the accumulation of Ag in leaves (677% and 1376%, respectively), while NH4SCN + Aspergillus, and (NH4)2S2O3 enhanced the accumulation in stems (7153% and 6717.5%). The Ag-accumulation in roots was stimulated by NH4SCN+ Aspergillus, and (NH4)2S2O3+ Aspergillus (132.5% and 178%, respectively), when compared to the control. The combination of NH4SCN+Aspergillus significantly enhanced the Cu-accumulation in leaves (228%); whereas NH4SCN+ Aspergillus, or (NH4)2S2O3+ Aspergillus resulted in greater accumulation of Cu in stems (1233.5% and 1580%, respectively) than the control. Results suggest that either NH4SCN or (NH4)2S2O3 (with or without Aspergillus) improved the accumulation of Au and Ag by B. napus. Accumulation of Au and Ag in plant organs overpassed the hyperaccumulation criterion (> 1 mg kg-1 of plant biomass); whereas Cu-accumulation in stems and roots also overpassed such criterion (> 1000 mg kg-1) by applying either NH4SCN or (NH4)2S2O3 + A. niger.

[Growth and photochemical efficiency of photosystem ii in seedlings of two varieties of Capsicum annuum L. inoculated with rhizobacteria and arbuscular mycorrhizal fungi]. / Crecimiento y eficiencia fotoquímica del fotosistema ii en plántulas de 2 variedades de Capsicum annuum L. inoculadas con rizobacterias u hongos micorrícicos arbusculares.

Plant growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) are a biological alternative for the sustainable management of Capsicum annuum L. This research work evaluated the effects of both PGPR and AMF on bell pepper and jalapeno pepper plants. Five bacterial strains isolated from several locations in Estado de Mexico were used: [P61 (Pseudomonas tolaasii), A46 (P. tolaasii), R44 (Bacillus pumilus), BSP1.1 (Paenibacillus sp.), and OLs-Sf5 (Pseudomonas sp.)], and three treatments with AMF [H1 (consortium isolated from pepper crops in the State of Puebla), H2 (Rhizophagus intraradices), and H3 (consortium isolated from the rhizosphere of lemon trees, State of Tabasco)]. In addition, a fertilized treatment (Steiner nutrient solution at 25%) and an unfertilized control were included. Seedlings of "Caloro" jalapeno pepper and "California Wonder" bell pepper were inoculated with AMF at seed sowing, and PGPR were inoculated after 15 days of seedling emergence; seedlings were grown under plant growth chamber conditions. P61 bacterium and H1 AMF consortia were the most effective microorganisms for jalapeno pepper whereas R44 bacterium and AMF H3 and H1 were the most effective for bell peppers, when compared to the unfertilized control. Furthermore, P61 and R44 bacteria showed beneficial effects on PSII efficiency.

[Nutrient transfer and growth of Pinus greggii Engelm. inoculated with edible ectomycorrhizal mushrooms in two substrates]. / Transferencia de nutrientes y crecimiento de Pinus greggii Engelm. inoculado con hongos comestibles ectomicorrícicos en dos sustratos.

An ectomycorrhiza is a mutualistic symbiosis of paramount importance in forestry and tree production. One of the selection criteria of ectomycorrhizal fungi that has currently gained importance is their edibility due to the economic, ecological and cultural relevance of edible ectomycorrhizal mushrooms as a non-timber forest product. The effect of the inoculation with three edible ectomycorrhizal mushrooms: Laccaria laccata, Laccaria bicolor y Hebeloma leucosarx, which are widely sold in Mexico, on the growth and nutrient contents of Pinus greggii grown in an experimental substrate and a commercial substrate enriched with a slow-release fertilizer, was evaluated. Two years after sowing, differences in terms of shoot and root biomass and macro and micronutrient contents between inoculated and non-inoculated plants, were recorded independently of the fungal species and the substrate. Despite the fact that plants grown in the commercial substrate had higher growth and nutrient contents, their ectomycorrhizal colonization percentages were smaller than those of the plants grown in the experimental substrate. The differences in the nutrient transfer to the inoculated plant shoots among the evaluated fungal species were recorded. Ca mobilization by L. laccata, Na by L. bicolor and Mn by H. leucosarx were observed in the plants growing in the experimental substrate. It has been demonstrated that the selection of substrates constitutes an important factor in the production of ectomycorrhizal plants and that the three evaluated species of edible ectomycorrhizal mushrooms have an enormous potential in the controlled mycorrhization of P. greggii.

Transferencia de nutrientes y crecimiento de Pinus greggii Engelm. inoculado con hongos comestibles ectomicorrícicos en dos sustratos / Nutrient transfer and growth of Pinus greggii Engelm. inoculated with edible ectomycorrhizal mushrooms in two substrates

La ectomicorriza es una simbiosis mutualista de enorme importancia en la producción de árboles de valor forestal. Uno de los criterios de selección de hongos ectomicorrícicos de gran interés es su comestibilidad, por la importancia económica, ecológica y cultural de los hongos comestibles ectomicorrícicos como un producto forestal no maderable. En este estudio se evaluó el efecto de la inoculación con los hongos comestibles ectomicorrícicos, Laccaria laccata, Laccaria bicolor y Hebeloma leucosarx, en el crecimiento y el contenido nutricional de Pinus greggii, crecido en un sustrato experimental, o en un sustrato comercial enriquecido con un fertilizante de liberación lenta. Dos años después de la siembra, se observaron diferencias en el crecimiento aéreo y radical y en el contenido de macro- y micronutrientes entre plantas inoculadas y no inoculadas, independientemente de la especie fúngica y del sustrato utilizado. Las plantas crecidas en el sustrato comercial tuvieron mayor crecimiento y contenido de nutrientes; sin embargo, sus porcentajes de colonización fueron menores que los de plantas crecidas en el sustrato experimental. Existieron diferencias en la transferencia de nutrientes a la parte aérea de las plantas inoculadas, al comparar entre las especies fúngicas implicadas. Se observó transferencia de Ca por L. laccata, de Na por L. bicolor y de Mn por H.leucosarx en el sustrato experimental. La selección de sustratos constituye un factor clave en la producción de plantas ectomicorrizadas y las tres especies de hongos comestibles ectomicorrícicos evaluados tienen un potencial relevante para la micorrización controlada de P. greggii.

An ectomycorrhiza is a mutualistic symbiosis of paramount importance in forestry and tree production. One of the selection criteria of ectomycorrhizal fungi that has currently gained importance is their edibility due to the economic, ecological and cultural relevance of edible ectomycorrhizal mushrooms as a non-timber forest product. The effect of the inoculation with three edible ectomycorrhizal mushrooms: Laccaria laccata, Laccaria bicolor y Hebeloma leucosarx, which are widely sold in Mexico, on the growth and nutrient contents of Pinus greggii grown in an experimental substrate and a commercial substrate enriched with a slow-release fertilizer, was evaluated. Two years after sowing, differences in terms of shoot and root biomass and macro and micronutrient contents between inoculated and non-inoculated plants, were recorded independently of the fungal species and the substrate. Despite the fact that plants grown in the commercial substrate had higher growth and nutrient contents, their ectomycorrhizal colonization percentages were smaller than those of the plants grown in the experimental substrate. The differences in the nutrient transfer to the inoculated plant shoots among the evaluated fungal species were recorded. Ca mobilization by L. laccata, Na by L. bicolor and Mn by H. leucosarx were observed in the plants growing in the experimental substrate. It has been demonstrated that the selection of substrates constitutes an important factor in the production of ectomycorrhizal plants and that the three evaluated species of edible ectomycorrhizal mushrooms have an enormous potential in the controlled mycorrhization of P. greggii.

Lipid extraction from the biomass of Trichoderma koningiopsis MX1 produced in a non-stirring culture for potential biodiesel production.

Oleaginous microorganisms such as microalgae, yeasts, bacteria and filamentous fungi are alternative sources of vegetal or animal fats for biodiesel production. This research evaluated the lipid production by the biomass Trichoderma koningiopsis MX1 with a non-stirring culture at room temperature, and fungal lipids were extracted through three techniques for biodiesel generation purposes. The three modified lipid extraction techniques yielded 18.4, 10.3 and 17.1 % of fungal lipids. The trans-esterification of lipids indicated that the controlling components for biodiesel were palmitic (40.8 %) and linoleic acids (ranging from 37.6 % to 41.2 %). Results show that fungal cultural conditions and the lipid extraction technique are determinants for producing biodiesel from fungal lipids. Therefore, the modification of some of these conditions could increase their efficiency and viability.

The Fatty Acid Profile Analysis of Cyperus laxus Used for Phytoremediation of Soils from Aged Oil Spill-Impacted Sites Revealed That This Is a C18:3 Plant Species.

The effect of recalcitrant hydrocarbons on the fatty acid profile from leaf, basal corm, and roots of Cyperus laxus plants cultivated in greenhouse phytoremediation systems of soils from aged oil spill-impacted sites containing from 16 to 340 g/Kg total hydrocarbons (THC) was assessed to investigate if this is a C18:3 species and if the hydrocarbon removal during the phytoremediation process has a relationship with the fatty acid profile of this plant. The fatty acid profile was specific to each vegetative organ and was strongly affected by the hydrocarbons level in the impacted sites. Leaf extracts of plants from uncontaminated soil produced palmitic acid (C16), octadecanoic acid (C18:0), unsaturated oleic acids (C18:1-C18:3), and unsaturated eichosanoic (C20:2-C20:3) acids with a noticeable absence of the unsaturated hexadecatrienoic acid (C16:3); this finding demonstrates, for the first time, that C. laxus is a C18:3 plant. In plants from the phytoremediation systems, the total fatty acid contents in the leaf and the corm were negatively affected by the hydrocarbons presence; however, the effect was positive in root. Interestingly, under contaminated conditions, unusual fatty acids such as odd numbered carbons (C15, C17, C21, and C23) and uncommon unsaturated chains (C20:3n6 and C20:4) were produced together with a remarkable quantity of C22:2 and C24:0 chains in the corm and the leaf. These results demonstrate that weathered hydrocarbons may drastically affect the lipidic composition of C. laxus at the fatty acid level, suggesting that this species adjusts the cover lipid composition in its vegetative organs, mainly in roots, in response to the weathered hydrocarbon presence and uptake during the phytoremediation process.

Bioleaching of gold, copper and nickel from waste cellular phone PCBs and computer goldfinger motherboards by two Aspergillus nigerstrains.

In an effort to develop alternate techniques to recover metals from waste electrical and electronic equipment (WEEE), this research evaluated the bioleaching efficiency of gold (Au), copper (Cu) and nickel (Ni) by two strains of Aspergillus niger in the presence of gold-plated finger integrated circuits found in computer motherboards (GFICMs) and cellular phone printed circuit boards (PCBs). These three metals were analyzed for their commercial value and their diverse applications in the industry. Au-bioleaching ranged from 42 to 1% for Aspergillus niger strain MXPE6; with the combination of Aspergillus niger MXPE6 + Aspergillus niger MX7, the Au-bioleaching was 87 and 28% for PCBs and GFICMs, respectively. In contrast, the bioleaching of Cu by Aspergillus niger MXPE6 was 24 and 5%; using the combination of both strains, the values were 0.2 and 29% for PCBs and GFICMs, respectively. Fungal Ni-leaching was only found for PCBs, but with no significant differences among treatments. Improvement of the metal recovery efficiency by means of fungal metabolism is also discussed.

Bioleaching of gold, copper and nickel from waste cellular phone PCBs and computer goldfinger motherboards by two Aspergillus nigerstrains

In an effort to develop alternate techniques to recover metals from waste electrical and electronic equipment (WEEE), this research evaluated the bioleaching efficiency of gold (Au), copper (Cu) and nickel (Ni) by two strains of Aspergillus niger in the presence of gold-plated finger integrated circuits found in computer motherboards (GFICMs) and cellular phone printed circuit boards (PCBs). These three metals were analyzed for their commercial value and their diverse applications in the industry. Au-bioleaching ranged from 42 to 1% for Aspergillus niger strain MXPE6; with the combination of Aspergillus niger MXPE6 + Aspergillus niger MX7, the Au-bioleaching was 87 and 28% for PCBs and GFICMs, respectively. In contrast, the bioleaching of Cu by Aspergillus niger MXPE6 was 24 and 5%; using the combination of both strains, the values were 0.2 and 29% for PCBs and GFICMs, respectively. Fungal Ni-leaching was only found for PCBs, but with no significant differences among treatments. Improvement of the metal recovery efficiency by means of fungal metabolism is also discussed.

[Casuarina equisetifolia (Casuarinaceae) growth in soil with diesel and application of biostimulation and bioaugmentation]. / Crecimiento de Casuarina equisetifolia (Casuarinaceae) en suelo con diésel, y aplicación de bioestimulación y bioaumentación.

Phytoremediation is an ecologically sound biotechnology directed to cleaning up contaminated soils. The study of tree species to treat petroleum contaminated soils is scarce; moreover, the combination of phytoremediation with bioaugmentation and biostimulation processes is also limited. Thus, this work evaluated the effects of the inoculation of Glomus intraradices, a bacterial consortium (M2BOS1-R2 and M2BOSI-F4) and Trichoderma viride, on the growth of Casuarina equisetifolia, fertilized with Floranid or Triple 17, when sown in a diesel-contaminated soil (7 500mg/kg). The factorial experiment 2x5x3 included 30 treatments with 10 replicates in a completely randomized design under greenhouse conditions for 120 days. Diesel significantly diminished plant height, total biomass, and plant index quality (PIQ). Glomus or bacterial consortium significantly increased plant height, total biomass and PIQ when compared to the inoculation of the three microorganisms or to the control. Floranid had negative effects on plant growth and PIQ at diesel contamination. Fertilization with Triple 17 combined with the three microorganisms stimulated plant growth in the absence of diesel, whereas in the presence of this contaminant the treatments combining Triple 17 with the bacterial consortium or with Trichoderma had better plant growth and PIQ. Mycorrhizal colonization was inhibited due to diesel contamination, and especially when Floranid was applied. The fertilizer Triple 17 (biostimulation) combined with the beneficial microorganisms (bioaugmentation) improved growth responses of C. equisetifolia in diesel-contaminated soil.

Crecimiento de Casuarina equisetifolia (Casuarinaceae) en suelo con diésel, y aplicación de bioestimulación y bioaumentación / Casuarina equisetifolia (Casuarinaceae) growth in soil with diesel and application of biostimulation and bioaugmentation

Phytoremediation is an ecologically sound biotechnology directed to cleaning up contaminated soils. The study of tree species to treat petroleum contaminated soils is scarce; moreover, the combination of phytoremediation with bioaugmentation and biostimulation processes is also limited. Thus, this work evaluated the effects of the inoculation of Glomus intraradices, a bacterial consortium (M2BOS1-R2 and M2BOSI-F4) and Trichoderma viride, on the growth of Casuarina equisetifolia, fertilized with Floranid® or Triple 17, when sown in a diesel-contaminated soil (7 500mg/kg). The factorial experiment 2x5x3 included 30 treatments with 10 replicates in a completely randomized design under greenhouse conditions for 120 days. Diesel significantly diminished plant height, total biomass, and plant index quality (PIQ). Glomus or bacterial consortium significantly increased plant height, total biomass and PIQ when compared to the inoculation of the three microorganisms or to the control. Floranid had negative effects on plant growth and PIQ at diesel contamination. Fertilization with Triple 17 combined with the three microorganisms stimulated plant growth in the absence of diesel, whereas in the presence of this contaminant the treatments combining Triple 17 with the bacterial consortium or with Trichoderma had better plant growth and PIQ. Mycorrhizal colonization was inhibited due to diesel contamination, and especially when Floranid was applied. The fertilizer Triple 17 (biostimulation) combined with the beneficial microorganisms (bioaugmentation) improved growth responses of C. equisetifolia in diesel-contaminated soil.

La fitorremediación es una biotecnología ecológicamente racional que está dirigida a la limpieza de suelos contaminados; sin embargo, el estudio de especies arbóreas para la fitorremediación de suelos con hidrocarburos del petróleo es limitado. Más aún, la combinación de la fitorremediación con procesos de bioaumentación y bioestimulación es también limitada. Por lo anterior, este estudio evaluó el efecto de la inoculación de Glomus intraradices, un consorcio bacteriano (M2BOS1-R2 y M2BOSI-F4) y Trichoderma viride en el crecimiento de plantas de Casuarina equisetifolia L. fertilizadas con Floranid® o Triple 17, en suelo contaminado con diésel (7 500mg/kg). El experimento factorial 2x5x3 incluyó 30 tratamientos y 10 repeticiones, distribuidos completamente al azar en invernadero, durante 120 días. El diésel disminuyó significativamente la altura, la biomasa total y el índice de calidad (ICP) de planta. Glomus o las bacterias aumentaron significativamente la altura, la biomasa seca total y el ICP con respecto al tratamiento sin inocular o con la triple inoculación. El Floranid redujo el crecimiento vegetal y el ICP, en presencia de diésel. El Triple 17 combinado con los tres microorganismos produjo mayor crecimiento vegetal en ausencia de contaminación, pero en presencia de diésel, el Triple 17 combinado con bacterias o con Trichoderma, estimuló la biomasa seca total y el ICP. La colonización micorrízica fue inhibida por el diesel, especialmente con la fertilización del Floranid. El Triple 17 (bioestimulación) combinado con los microorganismos (bioaumentación), favoreció el crecimiento de Casuarina en suelo contaminado con diésel.