Microbial Biofertilizers and Biopesticides: Nature’s Assets Fostering Sustainable Agriculture

New frontiers of soil fungal microbiome and its application for biotechnology in agriculture

The fungi-based technology provided encouraging scenarios in the transition from a conventionally based economic system to the potential security of sources closely associated with the agricultural sphere such as the agriculture. In recent years, the intensification of fungi-based processes has generated significant gains, additionally to the production of materials with significant benefits and strong environmental importance. Furthermore, the growing concern for human health, especially in the agriculture scenario, has fostered the investigation of organisms with high biological and beneficial potential for use in agricultural systems. Accordingly, this study offered a comprehensive review of the diversity of the soil fungal microbiome and its main applications in a biotechnological approach aimed at agriculture and food chain-related areas. Moreover, the spectrum of opportunities and the extensive optimization platform for obtaining fungi compounds and metabolites are discussed. Finally, future perspectives regarding the insurgency of innovations and challenges on the broad rise of visionary solutions applied to the biotechnology context are provided.

Bactericidal and plant defense elicitation activities of Eucalyptus oil decrease the severity of infections by Xylella fastidiosa on almond plants

The activity of Eucalyptus essential oil against eleven strains pertaining to six species of plant pathogenic bacteria was studied using growth inhibition and contact assays. All strains were susceptible to the formulation EGL2, and Xylella fastidiosa subspecies and Xanthomonas fragariae were the most sensitive. The bactericidal effect was strong causing 4.5 to 6.0 log reductions in survival in 30 min at concentrations in the range of 0.75 to 15.0 μl/ml depending on the bacteria tested. Transmission electron microscopy of the formulation EGL2 against the three X. fastidiosa subspecies studied allowed the observation of a strong lytic effect on bacterial cells. In addition, the preventive spray application of EGL2 to potted pear plants subsequently inoculated with Erwinia amylovora significantly decreased the severity of infections. Almond plants treated by endotherapy or soil drenching, and then inoculated with X. fastidiosa showed a significant decrease in disease severity as well as in the levels of the pathogen, depending on the strategy used (endotherapy/soil drenching, preventive/curative). The treatment by endotherapy in almond plants induced the expression of several genes involved in plant defense. It was concluded that the reduction of infections by the Eucalyptus oil treatments was due to the combination of its bactericidal and plant defense induction activities.

Ultrastructural and pathogenicity of Brevibacillus laterosporus against sinantropic muscoid dipterans

Brevibacillus laterosporus has entomopathogenic potential against several orders of insects and its wide bioactivity is associated with a variety of strain-specific molecules. In order to avoid the use of synthetic insecticides, along with the need to control insect pests, microbial control has been widely used. Muscoid dipterans are known for their medical-veterinary and sanitary importance, and synanthropy. The enormous biotechnological potential of B. laterosporus has been demonstrated, but there are still few studies with muscoid dipterans. The aim of the study was to verify the mortality of B. laterosporus NRS590 on synanthropic flies and to characterize its different cell stages ultrastructurally. The flies were collected from garbage bins and the colonies were adapted to the laboratory conditions. Bioassays with neo larvae were carried out from the bacterial growth in the phases: vegetative (6 hr), sporangium (20 hr), and free spores (44 hr). An aliquot of each phase was collected for Transmission (TEM) and Scanning Electron Microscopy (SEM). The effectiveness of NRS590 was observed in the sporulation phase, where the corrected mortality was 83.3, 85.1, and 99% for Chrysomya megacephala, Chrysomya putoria, and Musca domestica, respectively. The parasporal body was observed in detail on the entire spore surface. Although our knowledge of this bacterium is growing, it remains to be determined the real virulence factors responsible for the wide entomopathogenic activity observed on muscoid dipterans. Therefore, this study can provide subsidies for the improvement of efficient and safe microbial control techniques for the environment and living beings.