Producción de plántulas de chile habanero con fertilización orgánica y biológica

En los sistemas de cultivo se busca sustituir la fertilización química; por esto, se propone la alternativa de combinar a la composta con los fertilizantes orgánicos líquidos y biofertilizantes, para la obtención de plántulas de chile habanero de calidad. El objetivo de la investigación fue evaluar dos fertilizantes orgánicos líquidos en combinación con Purpureocillium lilacinum y Beauveria brongniartii en el crecimiento, concentración nutrimental y calidad de plántulas de chile habanero sobre el sustrato peat moss/composta, con el fin de sustituir la fertilización química. Se utilizó un diseño experimental completamente al azar con arreglo bifactorial, los factores fueron los fertilizantes orgánicos líquidos (lixiviado de vermicomposta y el producto comercial Pez Terra®, que sediluyeron en agua en una relación 1:200), y los biofertilizantes (B. brongniartii y P. lilacinum), también se evaluó un testigo (solución nutritiva de Steiner al 25%). Se encontró que las plántulas que se trataron con el producto comercial incrementaron su crecimiento, unidades SPAD, concentración de N, P y K, y la calidad; con la inoculación de P. lilacinum aumentó la altura de plántula, diámetro de tallo, área foliar, concentración de N e índice de esbeltez, con respecto a B. brongniartii. La interacción del fertilizante comercial y P. lilacinum, más el uso del sustrato peat moss/composta 1:1 (v/v), incrementaron la altura de plántula en 10%, área foliar en 35%, concentración de N en 57% y P en 35%, e índice de esbeltez en 8% en comparación con las plántulas que se produjeron con la solución nutritiva de Steiner al 25% y peat moss, por lo que esta combinación se consideró viable para la producción de plántulas de chile habanero y sustituir la fertilización química.

Антагонистическая активность энтомопатогенных грибов в отношении фитопатогенных микромицетов

The researches on evaluation the influence of entomopathogenic fungi of the genuses Beauveria, Isaria and Lecanicillium influence on phytopathogenic microorganisms Alternaria solani, Botrytis ciner-ea, Sclerotinia sclerotiorum, Rhizoctonia solani, Fusarium solani, Phytophtora alni are presented. The antifungal peculiarities of tested strains – a potential basis of complex action biological preparations for plant protection are shown in vitro. The highest level of antagonistic activity has been revealed in strains Beauveria brongniartii МХ, Lecanicillium sp. аph and Isaria fumosorosea 21-2.

Immune-Related Genes of Megalurothrips usitatus (Bagrall) Against Beauveria brongniartii and Akanthomyces attenuatus Identified Using RNA Sequencing

Megalurothrips usitatus (Bagrall) is an important pest of legumes worldwide, causing great economic loss every year. Beauveria brongniartii and Akanthomyces attenuatus have shown considerable pathogenicity against M. usitatus in our previous studies. The medial lethal concentration (LC50) and the sublethal lethal concentration (LC25) of B. brongniartii isolate SB010 against M. usitatus were 8.38 × 105 and 1.73 × 105 conidia mL−1, respectively, whereas those of A. attenuatus isolate SCAUDCL-53 against M. usitatus were 4.37 × 105 and 2.97 × 104 conidia mL−1, respectively. This study reports the transcriptome-based explanation of the stress responses of M. usitatus following the application of B. brongniartii and A. attenuatus. The analysis of the transcriptomic data revealed the expression of 254, 207, 195, and 234 immunity-related unigenes by M. usitatus in response to B. brongniartii LC50 (SB1), B. brongniartii LC25 (SB2), A. attenuatus LC50 (V1), and A. attenuatus LC25 (V2), respectively. The biological function and metabolic pathway analyses showed that these unigenes were mainly related to pattern recognition receptors, information transduction factors, and reaction factors, such as scavenger receptor, cytochrome b5, cuticle protein, lysozyme, and serine protease.

Improving Contagion and Horizontal Transmission of Entomopathogenic Fungi by the White-Spotted Longicorn Beetle, Anoplophora malasiaca, with Help of Contact Sex Pheromone

The white-spotted longicorn beetle, Anoplophora malasiaca, is one of the most destructive pests of horticultural crops and street trees. Effective controls are needed because the effect of marketed insecticides is limited. Entomopathogenic fungi offer a solution, and improving the rate of infection would be a breakthrough in this beetle’s control. The combination of pathogenic fungi and the beetle’s contact sex pheromone was suggested. The surface of the female body is covered with contact sex pheromone, which elicit male mating behavior. To develop a method for the practical control of this beetle, we evaluated the arrestant activity of female extract containing contact pheromone coated on a black glass model. Males presented with a coated model held on for 5 h (mean) during an 8-h experiment. In contrast, males presented with a control model held on for <0.3 h. Males that held onto coated models attached to fabric impregnated with conidia of the fungus Beauveria brongniartii picked up much conidia, which they then passed on to females during mating.

Toxicity and Biological Effects of Beauveria brongniartii Fe0 Nanoparticles against Spodoptera litura (Fabricius)

Nanotechnology has clear potential in the development of innovative insecticidal products for the biorational management of major insect pests. Metal-based nanoparticles of different microbial pest control agents have been effective against several pests. Synthesis of Beauveria brongniartii based Fe0 nanoparticles (Fe0NPs) and their bio-efficacy against Spodoptera litura was observed during this study. Beauveria brongniartii conidia were coated with Fe0NPs and characterized by applying a selection of different analytical techniques. Ultraviolet (UV) spectroscopy showed the characteristic band of surface plasmon at 430 nm; Scanning electron microscopy (SEM) images showed spherical shaped nanoparticles with a size ranging between 0.41 to 0.80 µm; Energy-dispersive X-ray (EDX) spectral analysis revealed characteristic Fe peaks at 6.5 and 7.1 Kev; the X-ray diffractogram showed three strong peaks at 2θ values of 45.72°, 64.47°, and 84.05°. The bioassay studies demonstrated that mortality of 2nd instar S. litura larvae following Fe0NPs treatment increased with increasing concentrations of Fe0NPs at different time intervals. The median lethal concentration (LC50) values of Fe0NPs against S. litura after seven days of fungal treatment was 59 ppm, whereas median survival time (LT50) values for 200 and 500 ppm concentrations of Fe0NPs against S. litura seven days post-treatment were 5.1 and 2.29 days, respectively. Beauveria brongniartii-Fe0NPs caused significant reductions in feeding and growth parameters (relative growth rate, relative consumption rate, and efficiency of conversion of ingested food) of S. litura. Beauveria brongniartii Fe0NPs induced reduction in glutathione-S-transferase activities throughout the infection period whereas activities of antioxidant enzymes decreased during later periods of infection. These findings suggest that B. brongniartii Fe0NPs can potentially be used in biorational S. litura management programs.

Production of Diverse Beauveriolide Analogs in Closely Related Fungi: a Rare Case of Fungal Chemodiversity

ABSTRACT Fungal chemodiversity is well known in part due to the production of diverse analogous compounds by a single biosynthetic gene cluster (BGC). Usually, similar or the same metabolites are produced by closely related fungal species under a given condition, the foundation of fungal chemotaxonomy. Here, we report a rare case of the production of the cyclodepsipeptide beauveriolides (BVDs) in three insect-pathogenic fungi. We found that the more closely related fungi Beauveria bassiana and Beauveria brongniartii produced structurally distinct analogs of BVDs, whereas the less-close relatives B. brongniartii and Cordyceps militaris biosynthesized structurally similar congeners under the same growth condition. It was verified that a conserved BGC containing four genes is responsible for BVD biosynthesis in three fungi, including a polyketide synthase (PKS) for the production of 3-hydroxy fatty acids (FAs) with chain length variations. In contrast to BVD production patterns, phylogenetic analysis of the BGC enzymes or enzyme domains largely resulted in the congruence relationship with fungal speciation. Feeding assays demonstrated that an FA with a chain length of eight carbon atoms was preferentially utilized, whereas an FA with a chain longer than 10 carbon atoms could not be used as a substrate for BVD biosynthesis. Insect survival assays suggested that the contribution of BVDs to fungal virulence might be associated with the susceptibility of insect species. The results of this study enrich the knowledge of fungal secondary metabolic diversity that can question the reliability of fungal chemotaxonomy. IMPORTANCE Fungal chemotaxonomy is an approach to classify fungi based on the fungal production profile of metabolites, especially the secondary metabolites. We found an atypical example that could question the reliability of fungal chemical classifications in this study, i.e., the more closely related entomopathogenic species Beauveria bassiana and Beauveria brongniartii produced structurally different congeners of the cyclodepsipeptide beauveriolides, whereas the rather divergent species B. brongniartii and Cordyceps militaris biosynthesized similar analogs under the same growth condition. The conserved biosynthetic gene cluster (BGC) containing four genes present in each species is responsible for beauveriolide production. In contrast to the compound formation profiles, the phylogenies of biosynthetic enzymes or enzymatic domains show associations with fungal speciation. Dependent on the insect species, production of beauveriolides may contribute to fungal virulence against the susceptible insect hosts. The findings in this study augment the diversity of fungal secondary metabolisms.