Cellulolytic Aerobic Bacteria Isolated from Agricultural and Forest Soils: An Overview.

This review provides insights into cellulolytic bacteria present in global forest and agricultural soils over a period of 11 years. It delves into the study of soil-dwelling cellulolytic bacteria and the enzymes they produce, cellulases, which are crucial in both soil formation and the carbon cycle. Forests and agricultural activities are significant contributors to the production of lignocellulosic biomass. Forest ecosystems, which are key carbon sinks, contain 20-30% cellulose in their leaf litter. Concurrently, the agricultural sector generates approximately 998 million tons of lignocellulosic waste annually. Predominant genera include Bacillus, Pseudomonas, Stenotrophomonas, and Streptomyces in forests and Bacillus, Streptomyces, Pseudomonas, and Arthrobacter in agricultural soils. Selection of cellulolytic bacteria is based on their hydrolysis ability, using artificial cellulose media and dyes like Congo red or iodine for detection. Some studies also measure cellulolytic activity in vitro. Notably, bacterial cellulose hydrolysis capability may not align with their cellulolytic enzyme production. Enzymes such as GH1, GH3, GH5, GH6, GH8, GH9, GH10, GH12, GH26, GH44, GH45, GH48, GH51, GH74, GH124, and GH148 are crucial, particularly GH48 for crystalline cellulose degradation. Conversely, bacteria with GH5 and GH9 often fail to degrade crystalline cellulose. Accurate identification of cellulolytic bacteria necessitates comprehensive genomic analysis, supplemented by additional proteomic and transcriptomic techniques. Cellulases, known for degrading cellulose, are also significant in healthcare, food, textiles, bio-washing, bleaching, paper production, ink removal, and biotechnology, emphasizing the importance of discovering novel cellulolytic strains in soil.

Plant density on yield of Husk tomato (Physalis ixocarpa Brot.) in field and greenhouse / Densidade vegetal no rendimento de tomate Husk (Physalis ixocarpa Brot.) em campo e casa de vegetação

ABSTRACT: Physalis ixocarpa Brot. (tomatillo or Husk tomato) is one of the five major vegetables cultivated in Mexico, but its yield in the field is low. However, greenhouse crops and the enhancement in plant density can promote an increase in yield per area. The aim of this research was to evaluate: yield, water consumption and water use efficiency of variety husk tomato 'Diamante'. The experiment was conducted under field and greenhouse conditions, during the two crop cycles (autumn-winter and spring-summer), with different planting densities (1.5, 2 and 3 plants m-2), in complete random blocks and three replications. The yield was influenced by the planting density and environments. In both environments, the planting density, with 3 plants m-2 increased yield 32 %, and 25% in water use efficiency (WUE). In greenhouse increased 32% yield m-2 and the WUE it was 18.1 kg m-3 while in the field was 16.4 kg m-3. Crop cycle spring-summer produced differences of 27% in plant length and 15% in stem diameter, probably due to the temperature that was 4 ºC higher with respect to autumn-winter.

RESUMO: Physalis ixocarpa Brot. (tomatillo ou tomate de cáscara) é um dos cinco principais vegetais cultivados no México, mas seu rendimento no campo é baixo. No entanto, as culturas em estufa e o aumento da densidade das plantas podem promover um aumento no rendimento por área. O objetivo desta pesquisa foi avaliar: rendimento, consumo de água e eficiência no uso da água do tomate de casca de variedade 'Diamante'. O experimento foi conduzido em condições de campo e casa de vegetação, durante os dois ciclos de cultivo (outono-inverno e primavera-verão), com diferentes densidades de plantio (1,5, 2 e 3 plantas m-2), em blocos aleatórios completos e três replicações. O rendimento foi influenciado pela densidade e pelos ambientes de plantio. Nos dois ambientes, a densidade de plantio, com três plantas m-2, aumentou a produtividade em 32% e em 25% na eficiência no uso da água (WUE). Em casa de vegetação aumentou 32% do rendimento m-2 e o WUE foi de 18,1 kg m-3, enquanto no campo foi de 16,4 kg m-3. O ciclo da safra primavera-verão produziu diferenças de 27% no comprimento das plantas e 15% no diâmetro do caule, provavelmente devido à temperatura 4 ºC maior em relação ao outono-inverno.

Mortality of Phyllophaga vetula larvae by the separate and combined application of Metarhizium anisopliae, Steinernema carpocapsae and Steinernema glaseri.

Phyllophaga spp. are a complex of edaphic insect pests that are present in the corn crops (Zea mays) in México, which are usually controlled with increasing dosages of broad-spectrum chemical insecticides. Several entomopathogenic nematode species can produce acceptable control levels of these larvae. However, the synergistic interaction between fungi and entomopathogenic nematodes (EPN) could improve the control of this insect. This study investigates the mortality of larvae of Phyllophaga vetula by the effect of the separate or combined application of the fungus Metarhizium anisopliae M1cog strain (Ma) and the nematodes Steinernema carpocapsae All strain (Sc) or Steinernema glaseri NJ-43 strain (Sg). In laboratory, dosages of 1 × 106 or 1 × 108 spores/larva and 250 infective juveniles were applied on medium or large size P. vetula larvae contained in vials with sterilized agricultural soil as the assay arena. The separate application of Ma did not kill any larvae, but Sg and Sc killed 40 and 80% of the larvae, respectively. However, the Ma and Sc combination had an important antagonistic interaction that decreased the mortality to 40%, but the combination Ma and Sg had a slight additive interaction that increased the mortality to 47%. The most determining factor in larvae mortality was the nematode used, with Sg as the species with best performance in 6 of the 12 treatments evaluated and with a maximum effectivity of 80% on medium-size larvae if combined with a low dosage of Ma. The combined application of an entomopathogenic fungus and EPN showed no consistent effects on the mortality percentage of P. vetula, mostly because the fungus was not isolated from Phyllophaga larvae.Phyllophaga spp. are a complex of edaphic insect pests that are present in the corn crops (Zea mays) in México, which are usually controlled with increasing dosages of broad-spectrum chemical insecticides. Several entomopathogenic nematode species can produce acceptable control levels of these larvae. However, the synergistic interaction between fungi and entomopathogenic nematodes (EPN) could improve the control of this insect. This study investigates the mortality of larvae of Phyllophaga vetula by the effect of the separate or combined application of the fungus Metarhizium anisopliae M1cog strain (Ma) and the nematodes Steinernema carpocapsae All strain (Sc) or Steinernema glaseri NJ-43 strain (Sg). In laboratory, dosages of 1 × 106 or 1 × 108 spores/larva and 250 infective juveniles were applied on medium or large size P. vetula larvae contained in vials with sterilized agricultural soil as the assay arena. The separate application of Ma did not kill any larvae, but Sg and Sc killed 40 and 80% of the larvae, respectively. However, the Ma and Sc combination had an important antagonistic interaction that decreased the mortality to 40%, but the combination Ma and Sg had a slight additive interaction that increased the mortality to 47%. The most determining factor in larvae mortality was the nematode used, with Sg as the species with best performance in 6 of the 12 treatments evaluated and with a maximum effectivity of 80% on medium-size larvae if combined with a low dosage of Ma. The combined application of an entomopathogenic fungus and EPN showed no consistent effects on the mortality percentage of P. vetula, mostly because the fungus was not isolated from Phyllophaga larvae.

Activity of Steinernema colombiense in plant-based oils.

Entomopathogenic nematodes (EPNs) are excellent biological control agents. Although traditionally EPN application targeted belowground insects, their aboveground use can be supported if combined with adjuvants. We hypothesized that EPN infective juveniles (IJs) could be combined with plant-based oils as adjuvants, without decreasing their efficacy against insect larvae under various scenarios. Specifically, our objectives were to evaluate the activity of Steinernema colombiense (Nematoda: Steinernematidae) when mixed with two plant-based oils (coconut and olive oils) and maintained at different temperatures and times, or combined with entomopathogenic fungi. First, we evaluated how these oils affected IJ survival and virulence against last instar Galleria mellonella (Lepidoptera: Pyralidae) larvae when maintained at five different temperatures (4, 8, 14, 20, and 24°C) and five incubation times (1, 3, 7, 14, and 21 days), using water as control treatment. Second, we evaluated virulence when combined with these two oils as well as with water (control) and combined with the entomopathogenic fungi (EPF), Beauveria bassiana (Hypocreales: Clavicipitaceae). Infective juvenile survival was higher in coconut than olive oil and water mixtures up to 7 days at 4°C. Conversely, olive oil supported higher larval mortality than coconut oil at 4 to 20°C and 14 days. Similarly, the number of days needed to kill insect larvae increased at extreme temperatures (4 and 24°C) after 14 days. Finally, the EPN + EPF combination showed an additive effect compared to EPN and EPF single treatments. Our findings indicate that our plant-based oil mixtures maintain viable IJs at moderate temperatures and up to 7 to 14 days, and can be used in single EPN mixtures or combined with EPF.Entomopathogenic nematodes (EPNs) are excellent biological control agents. Although traditionally EPN application targeted belowground insects, their aboveground use can be supported if combined with adjuvants. We hypothesized that EPN infective juveniles (IJs) could be combined with plant-based oils as adjuvants, without decreasing their efficacy against insect larvae under various scenarios. Specifically, our objectives were to evaluate the activity of Steinernema colombiense (Nematoda: Steinernematidae) when mixed with two plant-based oils (coconut and olive oils) and maintained at different temperatures and times, or combined with entomopathogenic fungi. First, we evaluated how these oils affected IJ survival and virulence against last instar Galleria mellonella (Lepidoptera: Pyralidae) larvae when maintained at five different temperatures (4, 8, 14, 20, and 24°C) and five incubation times (1, 3, 7, 14, and 21 days), using water as control treatment. Second, we evaluated virulence when combined with these two oils as well as with water (control) and combined with the entomopathogenic fungi (EPF), Beauveria bassiana (Hypocreales: Clavicipitaceae). Infective juvenile survival was higher in coconut than olive oil and water mixtures up to 7 days at 4°C. Conversely, olive oil supported higher larval mortality than coconut oil at 4 to 20°C and 14 days. Similarly, the number of days needed to kill insect larvae increased at extreme temperatures (4 and 24°C) after 14 days. Finally, the EPN + EPF combination showed an additive effect compared to EPN and EPF single treatments. Our findings indicate that our plant-based oil mixtures maintain viable IJs at moderate temperatures and up to 7 to 14 days, and can be used in single EPN mixtures or combined with EPF.

Seed and seedling quality of three chilis (Capsicum annuum L.) native to Oaxaca, Mexico / Qualidade de sementes e plântulas de três pimentas (Capsicum annuum L.) endêmicas de Oaxaca, México

ABSTRACT: The diversity of chilis in Oaxaca is one of the most extensive in Mexico. Growers select seeds in the traditional manner; information on its quality is unknown. The aim of this research was to compare the physical and physiological quality of seeds and seedlings of three native types to chili (Huacle, De agua and Pasilla) and of the commercial Green pepper as control. Fifteen variables were evaluated in seed and twelve in seedlings. The laboratory experiments were established under a completely randomized design. Means of the variables were compared using the Tukey test (α=0.05). Results showed that Pasilla chili had the highest values in seed size and weight, which was 1.44 g heavier than the control and 2.09 to 3.73 g higher than native types. Haucle chili and green pepper had a 90% germination rate, while chili De agua and Pasilla chili had germination rates of 51 and 38%, respectively. Huacle chili had the highest germination rate index (29.89) and seedling vigor index (992.25). The top highest values of number of normal seedlings were obtained in the control and Huacle chili seedlings (72 and 88%); also, the latter had the longest plumule (3.36 cm) and radicle (7.67 cm) values. Both Huacle and Pasilla chili seedlings had larger values in height, stem thickness, number of leaves, leaf area and slenderness index than De agua and Green pepper. Huacle chili had good physical and physiological quality similar to the seeds of the commercial Green pepper.

RESUMO: Oaxaca é umas das regiões de maior diversidade de espécies de pimentas do México. Os agricultores selecionam sementes da maneira tradicional; informações sobre sua qualidade são desconhecidas. O objetivo desta pesquisa foi comparar a qualidade física e fisiológica de sementes e mudas de três tipos nativos de pimenta (Huacle, De Agua e Pasilla) e pimenta verde comercial como controle. Quinze variáveis foram avaliadas em sementes e doze em mudas. As experiências de laboratório foram estabelecidas sob um delineamento inteiramente casualizado. As médias das variáveis foram comparadas pelo teste de Tukey (α=0.05). Os resultados mostraram que o Pasilla apresentou os maiores valores em tamanho e peso de sementes, 1,44 g mais pesado que o controle e 2,09 a 3,73 g maior que os demais tipos de pimenta nativa. A pimenta Huacle e a pimenta verde tiveram 90% de germinação de 90%, enquanto que De Agua e Pasilla foi de 51 e 38%, respectivamente. A pimienta Huacle apresentou os maiores índices de taxa de germinação (29,89) e de vigor de plântulas (992,25). Os maiores valores máximos no número de mudas normais foram obtidos no controle e na pimenta Huacle (72 e 88%). Além disso, este último apresentou os maiores valores de plúmula (3,36 cm) e radícula (7,67 cm). As mudas do Huacle e Pasilla apresentaram maiores valores em altura, espessura do caule, número de folhas, área foliar e índice de esbelto em relação à pimenta, De agua e ao controle. O Huacle apresentou boa qualidade física e fisiológica, semelhante às sementes da pimentão comercial.

Survival of Entomopathogenic Nematodes in Oil Emulsions and Control Effectiveness on Adult Engorged Ticks (Acari: Ixodida).

Although their control is based on chemical products, the infestations by ticks (Ixodes scapularis Say) are causing great losses and damages in the livestock production worldwide. In this study, the survival of the entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema carpocapsae and Steinernema websteri in vegetal oil suspension at concentrations of 13% and 33% and their effectiveness to control ticks at concentrations of 50 ± 5 and 100 ± 10 nematodes in oil suspensions of Cymbopogon citratus, Pelargonium sp, Juniperus virginiana, Rosa sp, and Mentha piperita were evaluated in lab conditions. In field conditions, the Lethal Concentration (LC90) of S. websteri in oil suspensions of J. virginiana and C. citratus in dogs infested with ticks was evaluated. In the laboratory, it was found that an oil emulsion of C. citratus and J. virginiana at 13% maintained the survival of S. carpocapsae, H. bacteriophora and S. websteri from 55% to 60% for a period of 96 hr. The combination of the S. websteri nematode with 50 or 100 nematodes in oil emulsions of J. virginiana at 33% presented a control effectiveness of 80-100% in adult ticks 24 hr post-application. In field, the LC90 of 119 juveniles of S. websteri in oil emulsions of J. virginiana at 33% on domestic dogs presented an accumulated a control effectiveness of 89% after 96 hr post-application. The combined application of J. virginiana and S. websteri could be a good alternative for the control of ticks. It was observed that the time of contact and the type of vegetable oil were crucial factors to increase the effectiveness of control.Although their control is based on chemical products, the infestations by ticks (Ixodes scapularis Say) are causing great losses and damages in the livestock production worldwide. In this study, the survival of the entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema carpocapsae and Steinernema websteri in vegetal oil suspension at concentrations of 13% and 33% and their effectiveness to control ticks at concentrations of 50 ± 5 and 100 ± 10 nematodes in oil suspensions of Cymbopogon citratus, Pelargonium sp, Juniperus virginiana, Rosa sp, and Mentha piperita were evaluated in lab conditions. In field conditions, the Lethal Concentration (LC90) of S. websteri in oil suspensions of J. virginiana and C. citratus in dogs infested with ticks was evaluated. In the laboratory, it was found that an oil emulsion of C. citratus and J. virginiana at 13% maintained the survival of S. carpocapsae, H. bacteriophora and S. websteri from 55% to 60% for a period of 96 hr. The combination of the S. websteri nematode with 50 or 100 nematodes in oil emulsions of J. virginiana at 33% presented a control effectiveness of 80­100% in adult ticks 24 hr post-application. In field, the LC90 of 119 juveniles of S. websteri in oil emulsions of J. virginiana at 33% on domestic dogs presented an accumulated a control effectiveness of 89% after 96 hr post-application. The combined application of J. virginiana and S. websteri could be a good alternative for the control of ticks. It was observed that the time of contact and the type of vegetable oil were crucial factors to increase the effectiveness of control.