Bioinspired Green Synthesis of Zinc Oxide Nanoparticles from a Native <i>Bacillus cereus</i> Strain RNT6: Characterization and Antibacterial Activity Against Rice Panicle Blight Pathogens <i>Burkholderia glumae</i> and <i>B. gladioli</i>

• Main Authors: Temoor Ahmed, Zhifeng Wu, Hubiao Jiang, Jinyan Luo, Muhammad Noman, Muhammad Shahid, Irfan Manzoor, Khaled S. Allemailem, Faris Alrumaihi, Bin Li
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Nanomaterials
• Subjects: antibacterial activity; biosynthesis; nanopesticides; rice pathogen; ZnONPs
• Online Access: https://www.mdpi.com/2079-4991/11/4/884

<i>Burkholderia glumae</i> and <i>B. gladioli</i> are seed-borne rice pathogens that cause bacterial panicle blight (BPB) disease, resulting in huge rice yield losses worldwide. However, the excessive use of chemical pesticides in agriculture has led to an increase in environmental toxicity. Microbe-mediated nanoparticles (NPs) have recently gained significant attention owing to their promising application in plant disease control. In the current study, we biologically synthesize zinc oxide nanoparticles (ZnONPs) from a native <i>Bacillus cereus</i> RNT6 strain, which was taxonomically identified using 16S rRNA gene analysis. The biosynthesis of ZnONPs in the reaction mixture was confirmed by using UV–Vis spectroscopy. Moreover, XRD, FTIR, SEM-EDS, and TEM analysis revealed the functional groups, crystalline nature, and spherical shape of ZnONPs with sizes ranging from 21 to 35 nm, respectively. Biogenic ZnONPs showed significant antibacterial activity at 50 µg mL⁻¹against <i>B. glumae</i> and <i>B. gladioli</i> with a 2.83 cm and 2.18 cm zone of inhibition, respectively, while cell numbers (measured by OD₆₀₀) of the two pathogens in broth culture were reduced by 71.2% and 68.1%, respectively. The ultrastructure studies revealed the morphological damage in ZnONPs-treated <i>B. glumae</i> and <i>B. gladioli</i> cells as compared to the corresponding control. The results of this study revealed that ZnONPs could be considered as promising nanopesticides to control BPB disease in rice.