1.D.180. The Phenazine Substance (PS) Family
Bacterial leaf streak caused by Xanthomonas oryzae pv. oryzicola (Xoc) is one of the most destructive diseases affecting rice production worldwide. Liu et al. 2022 extracted and purified phenazine substances from the secondary metabolites of Lysobacter antibioticus 13-6. The bacteriostatic mechanism of phenazine substances against Xoc was investigated through physiological responses and transcriptomic analyses. Phenazine substances affected the cell membrane permeability of Xoc, which caused cell swelling and deformation, blockage of flagellum synthesis, and imbalance of the intracellular environment. The changes in intracellular environment affected the physiological and metabolic functions of Xoc, which reduced the formation of pathogenic factors and pathogenicity. Through transcriptomic analyses, the expression of 595 genes was induced significantly (275 up-regulated and 320 down-regulated). In addition, phenazine substances affected three main functions of Xoc, i.e., transmembrane transporter activity, DNA-mediated transposition, and structural molecular activities. Phenazine substances also inhibits the potassium ion transport system that reduces Xoc resistance and induces the phosphate ion transport system to maintain stability of the internal environment. Finally, phenazine substances retarded cell growth and reduced the pathogenicity of Xoc. This provides insight into the antibacterial mechanism of phenazine substances against Xoc and provides guidance to the management of the incidence of bacterial leaf streak of rice (Liu et al. 2022).