Lop Nur, an extremely arid environment, harbors unique microbial resources and represents a potential reservoir for novel bioactive substances. With antibiotic resistance becoming an increasing global concern, the resistance traits of microorganisms in extreme habitats and their potential association with antibacterial activity remain poorly understood. This study aimed to investigate the diversity of soil microorganisms in Lop Nur, their resistance to norfloxacin, kanamycin, and amoxicillin, and their inhibitory activity against common pathogenic bacteria, thereby providing a scientific basis for the discovery of new antibacterial candidates. Surface soils from three sampling points in Lop Nur were inoculated onto Gao’s No.1 and LB media supplemented with different antibiotic regimens (single, pairwise, and triple combinations). Isolates were identified by 16S rRNA gene sequencing, their antibiotic resistance was assessed using the disk diffusion method, and antibacterial activity was evaluated using the agar well diffusion method. A total of 120 microorganisms were isolated, belonging to six phyla and nine genera, including 10 potential new species. The control group yielded the highest diversity (35 strains), whereas only 4 strains were recovered under triple-antibiotic treatment, demonstrating the strong selective effect of antibiotic stress. Resistance profiling showed that 88.14% of strains were resistant to amoxicillin, 64.71% to norfloxacin, and 60.68% to kanamycin, with multidrug resistance being widespread. Eleven strains exhibited antibacterial activity against five pathogens, including Staphylococcus aureus (maximum inhibition zone 53.51 mm), and nine of these strains also displayed antibiotic resistance, suggesting a potential association between resistance and antibacterial activity. Microorganisms isolated from Lop Nur displayed extensive resistance and notable antibacterial activity. Antibiotic stress strongly influenced the cultivable microbial isolates, facilitating the recovery of resistant strains with antibacterial potential. These findings provide a valuable reference for exploring microbial resources in extreme environments and highlight the potential link between antibiotic resistance and antibacterial activity.

Pear black spot, caused by A. gaisen during fruit growth, is a disease that significantly reduces pear yield. Biological control using antagonistic microorganisms is regarded as a viable alternative to chemical agents. The discovery of TRM76147, a novel species of Streptomyces isolated from the Taklamakan Desert, has demonstrated promising potential in addressing this issue. This study was conducted to determine the potential of crude extract of Streptomyces sp. nov., strain TRM76147, for control of A. gaisen. TRM76147 is closely related to Streptomyces griseoviridis NBRC 12874^T, exhibiting an average nucleotide identity (ANI) value of 82.13%. Combined with the polyphasic taxonomic identification, this suggests that TRM76147 is a potentially new species. Through analyses using BigSCAPE and antiSMASH, it was determined that the TRM76147 genome contains 19 gene clusters. The ethyl acetate extract of this strain demonstrates antifungal activity, with the active substance remaining stable at temperatures up to 70 °C, achieving an activity level of 16.23 ± 0.22 mm. Furthermore, the crude extract maintains its antifungal efficacy across a pH range of 2 to 12. Notably, the antifungal diameter was recorded at 16.53 ± 0.12 mm following 80 min of UV irradiation. Under different treatment conditions, TRM76147 fermentation crude extract caused A. gaisen spore crumpling and spore number reduction. In addition, this study also found that the TRM76147 fermentation broth could control the production of pear black spot disease, which initially revealed the inhibition mechanism. The abundant actinomycete resources in this study have good application and development value in the discovery of new species and the study of bioactive substances and biological control.