Vol. 8, Issue 9, Part I (2024)

Antibiotic resistance in plant pathogenic bacteria poses a significant threat to global agriculture and food security. With the discovery of penicillin in 1928, antibiotics have saved countless lives. However, there are now serious concerns of resistance acquired by bacteria due to their misuse and overuse. One major mechanism of antibiotic resistance in plant pathogenic bacteria involves the modification or degradation of antibiotics. Bacterial enzymes, such as beta-lactamases and aminoglycoside-modifying enzymes play a key role in breaking down the structure of antibiotics, rendering them ineffective, for instance, gene aadA1 and aadA2 encode enzyme aminoglycoside adenylyltransferases helps in degradation of streptomycin and develop resistance against Xanthomonas oryzae pv. oryzae. Horizontal gene transfer is another significant contributor to antibiotic resistance, the strA-strB streptomycin-resistance genes found on the Tn5393 transposon in Erwinia amylovora and X. campestris have presumably been acquired from nonpathogenic epiphytic bacteria under antibiotic selection. Mobile genetic elements, such as plasmids and transposons, facilitate the transfer of resistance genes between bacteria, allowing for the rapid spread of antibiotic resistance within bacterial populations. Additionally, bacteria may possess efflux pumps that actively pump out antibiotics from the bacterial cell, preventing their accumulation at lethal concentrations. Furthermore, the adaptive nature of bacteria contributes to antibiotic resistance through the development of mutations in target genes. For example OA-resistant mutants showed reduced or negligible virulence in an immature apple, which highlight the role of gyrA mutations in pathogenesis or survival of E. amylovora. The complex interplay between these resistance mechanisms emphasizes the need for a multifaceted approach to address antibiotic resistance in plant pathogenic bacteria. Strategies such as the development of new antibiotics, the use of combination therapies, and the implementation of agricultural practices that minimize the need for antibiotics can all contribute to a more sustainable and effective management of bacterial infections in crops.