Plant parasitic nematodes (PPNs) cause significant damage to crop production worldwide, leading to substantial economic losses. Conventional chemical nematicides are effective but frequently associated with environmental and health hazards. In response, biological control methods, particularly the use of microbial pesticides, have emerged as a sustainable and effective alternative. This study focuses on the isolation and characterization of Bacillus sp. HSY32, a bacterial strain with nematicidal properties, from a tropical rainforest soil sample in Hainan, China. Soil samples were screened for nematicidal activity, which led to the identification of the strain HSY32. Detailed observations using optical and scanning electron microscopy (SEM) revealed that HSY32 forms spores and parasporal crystal structures, which are typically associated with nematicidal Bacillus species. Genomic analysis of HSY32 showed that its genome spans 6,711,949 base pairs and contains 7915 predicted genes, with an average GC content of 35.4%. Phylogenetic analysis, utilizing 16S rRNA sequences and average nucleotide identity (ANI), established that HSY32 is closely related to Bacillus mobilis, a known species within the Bacillus genus. Further genomic analysis using local BLAST identified several toxin genes with high similarity to known nematicidal genes, including cry4Ba, cry50Ba, app6Ba, cry70Bb, and tpp36Aa. To confirm the functionality of these toxin genes, they were cloned into pET-30a expression vectors and expressed in E. coli BL21 (DE3) cells. Among the expressed proteins, the Cry4Ba-like protein, with a molecular weight of approximately 110 kDa, was found to exhibit significant nematicidal activity in bioassays. This protein demonstrated the ability to kill or inhibit the growth of PPNs, indicating its potential as a biological control agent. The successful isolation of Bacillus strain HSY32 and the identification of its novel Cry4-like toxin gene represent a significant advancement in the field of biological control of plant parasitic nematodes. The nematicidal activity of the Cry4Ba-like protein highlights the potential of HSY32 as a source of new biopesticides. Further studies are required to enhance the production and application of these biocontrol agents in agriculture, paving the way for more sustainable and eco-friendly methods to control PPNs.

Rotylenchulus reniformis poses a significant threat to cotton crops in the Brazilian Cerrado, particularly when grown consecutively with soybeans. This nematode has not only become a concern for cotton but has also led to considerable damage in soybean crops, emphasizing the need for effective nematode control in both agricultural settings. The aim of this study was to combine genetic control with the application of biological nematicides, as seed treatment, to manage R. reniformis under greenhouse conditions. Two soybean cultivars, TMG 4182 and Fibra, resistant and susceptible, were used and the biological nematicides used included Purpureocillium lilacinum, Trichoderma harzianum + T. asperellum + Bacillus amyloliquefaciens, B. subtilis + B. licheniformis, and B. firmus. Inoculation with 800 R. reniformis occurred in the cotyledonary stage, with evaluations conducted at 72 and 76 days after inoculation for Experiments 1 and 2, respectively. Nematodes were extracted from the soil and roots, calculating the reproduction factor (RF). The combination of biological nematicides with resistant cultivars did not yield substantial benefits in controlling reniform nematodes in soybean but safeguarding resistant cultivars through the application of chemical or biological nematicides is important to mitigate inoculum pressure on resistance genes. In addition, biological nematicides evaluated in this study did not improve soybean plant development and we concluded that managing reniform nematodes in soybean necessitates the integration of diverse control measures to effectively address the challenges posed by this nematode's impact on crops.

Caffeine, a significant naturally occurring alkaloid in beverages like tea and coffee, can be degraded by bacteria. Prolonged caffeine consumption can stimulate adrenal glands, cause irregular muscle activity, cardiac arrhythmias, and withdrawal symptoms such as headaches and fatigue. Beyond its health-related concerns, the environmental impact of caffeine degradation is noteworthy. Effluents from coffee industries contain high caffeine concentrations, and the discharge of such effluents into lakes poses a risk to the portability of drinking water. This study isolated a novel bacterium from agricultural soil, identified as Bacillus sp. KS38 through 16 S rRNA gene sequencing, which can metabolize caffeine as the sole carbon and nitrogen source. The bacterium exhibited Gram-positive characteristics. Response surface methodology (RSM) optimized bacterial growth conditions. The relevant parameter for the degradation of caffeine was obtained by first screening the parameters using the Plackett-Burman design. Using central composite design (CCD) and RSM, the important parameters were determined to achieve the ideal degradation conditions. The identified the ideal degradation conditions: 0.66 g/L caffeine, 0.85 g/L glucose, pH 6.83, and 20.5 degrees C. RSM predicted a bacterial growth of 0.591, which was confirmed experimentally. This bacterium has potential applications in wastewater treatment and caffeine bioremediation.