BsR1, a broad-spectrum antibacterial peptide with potential for plant protection.

Abstract

The urgent need for new antibacterial drugs arises from the emergence of bacterial multidrug resistance due to antibiotic overuse. Antimicrobial peptides, crucial components of innate immunity in animals and plants, exhibit effectiveness against multidrug-resistant bacteria while minimizing the development of drug resistance. In this study, the antibacterial peptide BsR1, comprising 21 amino acids, was finalized by predicting the active site of an antifungal gene and sequence optimization. BsR1 displayed broad-spectrum antibacterial activities against diverse Gram-positive and Gram-negative bacteria, with a low minimum inhibitory concentration of 4.25-17 μM. Stability experiments demonstrated that BsR1 has high resistance to thermal, ultraviolet, and acid-base conditions, while revealing increased sensitivity to divalent ions Ca2+ and Mg2+. The mode of action of BsR1 involved cell membrane damage, leading to bacterial cell structure disruption and subsequent death. Secondary structure prediction indicated a linear helical conformation with a positive charge of +7.5, facilitating its interaction with the target cell membrane. BsR1 exhibited excellent biological safety, as it did not induce necrosis in tobacco leaves, and the low observed hemolytic effect on mammalian cells with a value of 3.26%. Additionally, BsR1 demonstrated the ability to enhance disease resistance in rice and effectively curbed the spread of rice bacterial blight. This research presents BsR1 as a novel approach and potential medication in the development of antibacterial drugs, offering a valuable tool in combating pathogenic microorganisms, particularly in plants.IMPORTANCEThis study addresses the critical need for new antibacterial drugs in the face of bacterial multidrug resistance resulting from antibiotic overuse. It highlights the significance of antimicrobial peptides as essential components of innate immunity in animals and plants, which have been proven effective against multidrug-resistant bacteria and are difficult to develop resistance against. This study successfully synthesizes a broad-spectrum antibacterial peptide, BsR1, with strong inhibitory activities against various Gram-positive and Gram-negative bacteria. BsR1 demonstrates favorable stability and a mode of action that damages bacterial cell membranes, leading to cell death. It also exhibits biological safety and shows potential in enhancing disease resistance in rice. This research offers a novel approach and potential medication for antibacterial drug development, presenting a valuable tool in combating pathogenic microorganisms, particularly in plants.