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In this study, the antagonistic potential of Trichoderma erinaceum 10-15 and T. virens 32-09 against the nematode Meloidogyne incognita was evaluated in tomato (Solanum lycopersicum L.) plants. A solution of 106 conidia mL-1 of each strain was inoculated on tomato plants, and the variables of nematode control, galling index, eggs per gram of root, and females per gram of root were determined. The in vitro antagonism of Trichoderma filtrates on the hatching of eggs and J2 juveniles of M. incognita was evaluated. The results were used for analysis of variance and comparison of means using the Tukey method (p ≤ 0.05). Control variables of the phytopathogen on S. lycopersicum were determined by measuring the area under the disease progress curve (AUDPC), the Weibull parameter, the coefficient of determination, and the final severity of root damage. T. erinaceum 10-15 showed a greater inhibitory effect on M. incognita, relative to T. virens 32-09. Both strains evaluated showed significant differences in comparison to the uninoculated control, resulting in a 60 % reduction in juvenile stage mobility and egg hatching, as well as greater control of the phytonematode in the AUDPC variables, Weibull parameter, and final severity under controlled conditions. The strain T. erinaceum 10-15 showed a better antagonistic effect on egg formation at 68 days, at 60.3 %, and on reducing the number of M. incognita females with at 60 days, at 80.6 %. Both T. erinaceum 10-15 and T. virens 32-09 were found to be potential biocontrol agents of M. incognita in S. lycopersicum. [ABSTRACT FROM AUTHOR]

This work was carried out to evaluate the insecticidal effect of mono, bi and trimetallic nanoparticles (NPs) from leaf extract of habanero pepper (Capsicum chinense Jacq.) on the red flour beetle (Tribolium castaneum herbst.) and cotton mealybug (Phenacoccus solenopsis Tinsley). The results showed that Cu NPs, Cu/Mn NPs and Zn/Cu NPs had high insecticidal effect against T. castaneum (63%-80% mortality after 96 h). The Cu NPs and Zn/Cu NPs showed also insecticidal effect against P. solenopsis, but to a lesser extent (20%-28% after 96 h). With regards to the physicochemical characterization, Cu NPs had a zeta potential of 21.1 mV, whereas Cu/Mn NPs and Zn/Cu NPs exhibited zeta potentials of 200 mV. The polydispersity index (PDI) values for Cu NPs, Cu/Mn NPs, and Zn/Cu NPs were 10.1, 29.16, and 14.34, respectively. The TF-IR spectra of the NPs varied from 600 to 4000 cm-1. The EDX weight percentages showed the presence of Cu (0.29%-2.4%), Mn (1.4%), and Zn (2.6%) in Cu/Mn NPs and Zn/Cu NPs, respectively. [ABSTRACT FROM AUTHOR]

The evaluation of biorrational products to control the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is of primary importance in the agriculture sector. In this study, we evaluated the effects of commercial botanical acaricides (BAs) on T. urticae and its predatory mite Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae). In the laboratory, T. urticae was exposed to acaricide-immersed leaves and A. swirskii to acaricide-coated glass vials. In the greenhouse, potted eggplants infested with mites were sprayed with different BAs. In the laboratory, Zea mays oil-based and Glycine max oil-based BAs caused more than 95% and 80% mortality of adults after 48 h of application and caused also 100% mortality of eggs. Residual exposure of A. swirskii adults to the BAs caused 45–60% mortality. In the greenhouse, these BAs caused more than 50% decrease in the population of T. urticae for 21 d. [ABSTRACT FROM AUTHOR]

Induced systemic resistance (ISR) is a mechanism involved in the plant defense response against pathogens. Certain members of the Bacillus genus are able to promote the ISR by maintaining a healthy photosynthetic apparatus, which prepares the plant for future stress situations. The goal of the present study was to analyze the effect of the inoculation of Bacillus on the expression of genes involved in plant responses to pathogens, as a part of the ISR, during the interaction of Capsicum chinense infected with PepGMV. The effects of the inoculation of the Bacillus strains in pepper plants infected with PepGMV were evaluated by observing the accumulation of viral DNA and the visible symptoms of pepper plants during a time-course experiment in greenhouse and in in vitro experiments. The relative expression of the defense genes CcNPR1, CcPR10, and CcCOI1 were also evaluated. The results showed that the plants inoculated with Bacillus subtilis K47, Bacillus cereus K46, and Bacillus sp. M9 had a reduction in the PepGMV viral titer, and the symptoms in these plants were less severe compared to the plants infected with PepGMV and non-inoculated with Bacillus. Additionally, an increase in the transcript levels of CcNPR1, CcPR10, and CcCOI1 was observed in plants inoculated with Bacillus strains. Our results suggest that the inoculation of Bacillus strains interferes with the viral replication, through the increase in the transcription of pathogenesis-related genes, which is reflected in a lowered plant symptomatology and an improved yield in the greenhouse, regardless of PepGMV infection status. [ABSTRACT FROM AUTHOR]

Commercial formulations of two entomopathogenic fungi (Metarhizium anisopliae Metschnikoff and Beauveria bassiana Balsamo) and two strains of Bacillus thuringiensis (B. thuringiensis var. kurstaki and B. thuringiensis var. aizawai) were evaluated against S. frugiperda and H. zea in two fields in the Yucatan Peninsula. In both locations, M. anisopliae and B. bassiana had similar efficacy (Davis and Williams scale for final damage of 1.2–1.3 at Becal and 1.7–2.6 at Muna) to that of emamectin benzoate (damage level 1.4 in Becal and 2.0 in Muna) on suppressing leaf damage by S. frugiperda. These fungal-based insecticides also caused a decrease in the ear damage by H. zea. Grain yield of plots treated with these fungal-based insecticides (5900–7500 kg ha−1) was similar to that treated with emamectin benzoate (7400–7500 kg ha−1). [ABSTRACT FROM AUTHOR]

Objective: To develop a protocol for the aseptic in vitro establishment and multiplication of Aechmea fasciata (Lindl.) Baker. Design/Methodology/Approach: Different concentrations of NaClO (2, 3, 4, and 5%) were assessed for the aseptic establishment of A. fasciata. During the shoot induction stage, the three following treatments were tested: T1 = 6-benzyladenine + naphthalene-1-acetic acid (BA + ANA; 5 + 2 mg L-1); T2 = zeatin + 2,4-dichlorophenoxyacetic acid (Zea + 2,4-D; 5 + 2 mg L-1); and T3 = control with no plant growth regulators. During the shoot multiplication stage, three more treatments were assessed: T1 = Zea + 2,4-D (2.5 + 1 mg L-1); T2 = Zea + 2,4-D (5 + 2 mg L-1); and T3 = Zea + 2,4-D + gibberellic acid (AG3) (2.5 + 1 + 3.5 mg L-1). To assess the number of cellular events, different nitrate concentrations were tested in the medium (18.8, 39.4, and 60 mM NO3-). Finally, during the shoot regeneration stage, nine treatments derived from the combination of three concentrations of kinetin (KIN: 0, 0.1, and 0.5 mg L-1) and of indole-3-acetic acid (AIA: 0, 0.3, and 0.4) were assessed. Completely randomized designs were used in each stage. Duncan’s test (p ≤ 0.05) was used to compare the means during the shoot induction and multiplication stages. A regression analysis was carried out to study the aseptic establishment and a non-parametric test (Kruskal-Wallis) was made to assess the “amount of microshoots during regeneration” variable. Results: A. fasciata aseptic explants with 4% NaClO were established. Shoot induction was most effective with the BA + ANA (5 + 2 mg L-1) treatment. The highest callus production was reported with the Zea + 2,4-D (5 + 2 mg L-1) treatment. The largest number of microshoots was obtained with high nitrate doses. Meanwhile, the most successful regeneration was achieved with the 0.1 mg KIN L-1 and 0.4 mg AIA L-1 treatment. Study Limitations/Implications: The application of Zea and 2,4-D during multiplication induced callus formation. Findings/Conclusions: Apical bud explants in an MS medium with BA and ANA present organogenesis. The use of Zea and 2,4-D forms calluses in the already established in vitro shoots, which regenerate with the use of KIN and AIA. Better microshoot coloring and development were achieved with MS salts, which have a medium nitrate content. [ABSTRACT FROM AUTHOR]

In order to find native isolates of Bacillus thuringiensis, in the present work isolations were made from different materials obtained from the southeast of Mexico, in the period from March 2014 to July 2015. Bacterial colonies were selected based on the typical characteristics of the Bacillus genus and were identified as Bacillus thuringiensis, based on the presence of parasporal crystals, cry gene, hag gene, protein profile and insecticidal activity. An isolate of soil samples (ITCBT34) and two larvae of Chlosyne lacinia (ITCBT61, ITCBT62) was obtained. These isolates presented amplification of the cry and hag genes. Isolate ITCBT34 presented crystals with oval morphology, while isolates ITCBT61 and ITCCBT62 presented dipyramidal crystals. Differences were observed in the size of the fragment produced by the ampl ification of the hag gene and in the protein profile of the different isolates. The insecticidal activity was determined by crude bioassay with a concentration of 10 μg cm-2. The threeisolates caused 100% mortality of Manduca sexta larvae at 96 h of exposure. Isolates ITCBT61 and ITCBT62 showed morphological characteristics and size of the hag gene similar to the reference strain B. thuringiensis svar. kurstaki HD1, the isolate ITCBT34 showed no similarity, so it could be an isolate not related to serovar kurstaki HD1. [ABSTRACT FROM AUTHOR]

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The use of microbial inoculants is a viable alternative to nurture crops and increase productivity without damaging the soil. The objective of this study was to evaluate the effect of microbial inoculants on growth and productivity of habanero pepper (Capsicum chinense Jacq.) in a greenhouse conditions. The study was conducted in Conkal, Yucatan, Mexico, from September to December 2012. Three inoculants and a control (without application of inoculant) were evaluated under commercial chemical fertilizer. A completely randomized design was used and treatments were Rhizophagus irregularis (one spore mL-1), Pseudomonas spp. (1×106 cfu mL-1) and Azospirillum brasilense (1×106 cfu mL-1). ANOVA and Tukey's comparison of means (p⩽0.05) were performed using SAS. The application of inoculants was performed during transplantation and response variables were growth, productivity and foliage nutrient content (N, P, K). The plants treated with Pseudomonas spp. were significantly higher, and showed greater stem diameter and total dry biomass than the control plants 120 d after transplanting. In this same treatment the highest yield (899.84 g per plant) was obtained and fruits were larger, with greater diameter and weight. The mineral content of leaves was not different (p>0.05) between the plants treated with inoculants and those of the control. Inoculation of Pseudomonas spp. to habanero pepper during transplantation enhances growth, yield and fruit size. [ABSTRACT FROM AUTHOR]

Corynespora cassiicola is a pathogen that causes lesions in different organs of tomato crops. For its control, synthetic fungicides are used that require more than one application. Trichoderma spp. is a highly interactive saprophytic fungus in the rhizosphere known as a biological control agent against plant diseases and promoter of plant growth due to its different modes of action. The effect on physiological and growth variables in Solanum lycopersicum plants inoculated with spore concentrations 1x100, 1x105, 1x106, 1x107 and 1x108 of Trichoderma asperellum Ta-13-17 and Fithan®, (as a commercial control) was evaluated. As a biocontrol agent for C. cassiicola under protected conditions. The 1x106, 1x108 and Fithan® treatments obtained the highest photosynthetic rates with 20.7, 20.6 and 19.6 µmol m-2 s-1 respectively. The 1x108 conidia mL-1 treatment obtained the highest means in the photosynthesis variables 20.6 µmol m-2 s-1, yield 1347.02 g per plant and presented a lower percentage of final severity, lower speed in the distribution of the disease and lower accumulation of area under the disease progress curve. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of inoculation with Bacillus spp. isolates on the photosynthetic apparatus of Capsicum chinense plants infected with PepGMV. In vitro and greenhouse experiments were performed to evaluate whether the inoculation improved plants' performance through the increase in photosynthetic efficiency to control PepGMV. The results showed that despite PepGMV infection, the plants inoculated with some isolates of Bacillus spp. had a healthy photosynthetic mechanism, as the photochemical parameters and gas exchange increased. The maximum photochemical quantum yield of PSII (Fv/Fm) of plants with PepGMV and inoculated with Bacillus isolates (M9, K46, and K47) increased (7.85, 7.09, and 7.77%, respectively) with respect to uninoculated controls. In inoculated plants, the CO2 assimilation rate increased and the transpiration rate decreased, therefore indicating an increased water use efficiency. This effect was reflected by the less severe symptoms caused by PepGMV in the plants obtained from seeds inoculated with different Bacillus spp. Plants inoculated with K47 isolates showed an increase in fruit yield and quality. This study suggests that it is possible to protect, at the greenhouse level, C. chinense plants from PepGMV through selected rhizobacteria inoculation. [ABSTRACT FROM AUTHOR]

Bacillus is one of the main rhizobacteria to have been used as a study model for understanding many processes. However, their impact on photosynthetic metabolism has been poorly studied. The aim of this study was to evaluate the physiological parameters of pepper (Capsicum chinense Jacq.) plants inoculated with Bacillus spp. strains. Pepper seeds were inoculated with Bacillus cereus (K46 strain) and Bacillus spp. (M9 strain; a mixture of B. subtilis and B. amyloliquefaciens), chlorophyll fluorescence and gas exchange were evaluated. The ANOVA (P ≤ 0.05) showed that the maximum photochemical quantum yield of photosystem II (PSII) (Fv/Fm) in plants inoculated with the M9 strain (0.784) increased with respect to other treatments (K46: 0.744 and Control: 0.739). Inoculated plants with M9 and K46 strains exhibited an increase of both photochemical quenching (qP) (by 27% and 24%, respectively) and CO2 assimilation rate (photosynthesis) (by 20% and 16%, respectively), when compared with non-inoculated plants. Furthermore, plants inoculated with M9 and K46 showed decreased transpiration (61% and 57%, respectively) with respect to controls. Likewise, both electron transport rate of PSII (ETR) and PSII operating efficiency (ΦPSII) increased in inoculated plants. However, only plants inoculated with the M9 strain showed enhancements on all growth characteristics. Our results therefore show that inoculating plants with M9 strain positively influenced the performance of the photosynthetic mechanism in pepper plants to increase chlorophyll fluorescence and gas exchange parameters. Promotion of photosynthetic capacity in pepper was due to increased ETR in the thylakoid membranes, which was promoted by the bacteria. M9 strain could even be used in sustainable agriculture programs. [ABSTRACT FROM AUTHOR]

Practically all Bacillus thuringiensis strains contain a set of self-replicating, extrachromosomal DNA molecules or plasmids, which vary in number and size in the different strains. The plasmid patterns obtained from gel electrophoresis have previously been used as a tool to characterize strains, but comparison of the plasmid patterns has been limited in the number and diversity of strains analyzed. In this report, we were able to compare the plasmid patterns of 83 type strains (out of 84) and 47 additional strains from six serotypes. The information obtained from this comparison showed the importance of this tool as a strain characterization procedure and indicates the complexity and uniqueness of this feature. For example, with one exception, all type strains showed a unique plasmid pattern. All were unique in such a way that none showed even a single comigrating plasmid in the agarose gels, and therefore, cluster analysis was impossible, indicating that plasmid patterns are qualitative rather than quantitative features. Furthermore, comparison between strains belonging to the same serotype showed a great difference in variability. Some serotypes (e.g., israelensis) showed the same basic pattern among all its strains, while other serotypes (e.g., morrisoni) showed a great diversity of patterns. These results indicate that plasmid patterns are valuable tools to discriminate strains below the serotype level.