Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, People's Republic of China.
Department of Plant Pathology, University of California, Davis, CA, U.S.A.
Phytopathology. 2019 Nov;109(11):1849-1858. doi: 10.1094/PHYTO-05-19-0152-R. Epub 2019 Oct 2.
is the causal agent of bacterial canker of tomato, which causes significant economic losses because of the lack of resistant tomato varieties. Chemical control with streptomycin or cupric bactericides is the last defensive line in canker disease management. Streptomycin is an aminoglycoside antibiotic that inhibits protein synthesis and targets the 30S ribosomal protein RpsL. Streptomycin has been used to control multiple plant bacterial diseases. However, identification and characterization of streptomycin resistance in have remained unexplored. In this study, a naturally occurring strain TX-0702 exhibiting spontaneous streptomycin resistance was identified, with a minimum inhibitory concentration of 128 μg/ml. Additionally, an induced streptomycin-resistant strain BT-0505-R was generated by experimental evolution of the sensitive strain BT-0505. Genome sequencing and functional analyses were used to identify the genes conferring resistance. A point mutation at the 128th nucleotide in the gene of strain BT-0505-R is responsible for conferring streptomycin resistance. However, in TX-0702, resistance is not attributed to mutation of , streptomycin inactivation enzymes, or multidrug efflux pumps. The mechanism of resistance in TX-0702 is independent of previously reported bacterial loci. Taken together, these data highlight diverse mechanisms used by a Gram-positive plant pathogenic bacterium to confer antibiotic resistance.
是番茄细菌性溃疡病的病原体，由于缺乏抗番茄品种，该病会造成严重的经济损失。用链霉素或铜杀菌剂进行化学防治是溃疡病防治的最后一道防线。链霉素是一种氨基糖苷类抗生素，它抑制蛋白质合成，并靶向 30S 核糖体蛋白 RpsL。链霉素已被用于控制多种植物细菌性疾病。然而，对 中链霉素抗性的鉴定和表征仍未得到探索。在本研究中，鉴定出一株自然发生的具有自发链霉素抗性的 菌株 TX-0702，其最小抑菌浓度为 128μg/ml。此外，通过敏感菌株 BT-0505 的实验进化，产生了一株诱导的链霉素抗性菌株 BT-0505-R。通过基因组测序和功能分析鉴定出赋予抗性的基因。BT-0505-R 菌株中 基因的第 128 个核苷酸的点突变是赋予链霉素抗性的原因。然而，在 TX-0702 中，抗性不是由于 、链霉素失活酶或多药外排泵的突变引起的。TX-0702 中的耐药机制与先前报道的细菌基因座无关。总之，这些数据突出了革兰氏阳性植物病原细菌赋予抗生素抗性的不同机制。
