Kang Beom Ryong, Anderson Anne J, Kim Young Cheol
a Department of Applied Biology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, South Korea.
b Department of Biological Engineering, Utah State University, Logan, UT 84322-4105, USA.
Can J Microbiol. 2019 Mar;65(3):185-190. doi: 10.1139/cjm-2018-0372. Epub 2018 Nov 6.
A biocontrol bacterium, Pseudomonas chlororaphis O6 promotes plant health through multifaceted mechanisms. In this study, we used P. chlororaphis O6 mutants to examine metabolites with aphicidal activity. Direct application of intact P. chlororaphis cells to the surface of second-instar nymphs of the green peach aphid resulted in no mortality. However, nymphs died when exposed only to the volatiles produced by the P. chlororaphis O6 wild-type strain grown on rich media. Mutants lacking the production of two antibiotics, phenazine and pyrrolnitrin, or the insect toxin FitD retained the aphicidal potential of the wild-type strain. However, the volatiles produced by mutants deficient in the production of hydrogen cyanide (HCN) or defective in the synthesis of the global regulator GacS, which regulates HCN synthesis, showed no aphicidal activity. Direct application of potassium cyanide caused mortality of green peach aphid nymphs. These results indicate that HCN production by a plant probiotic is involved in preventing insect growth.
一种生防细菌，绿针假单胞菌O6通过多方面机制促进植物健康。在本研究中，我们使用绿针假单胞菌O6突变体来检测具有杀蚜活性的代谢产物。将完整的绿针假单胞菌细胞直接施用于桃蚜二龄若虫表面不会导致死亡。然而，若虫仅暴露于在丰富培养基上生长的绿针假单胞菌O6野生型菌株产生的挥发物时会死亡。缺乏两种抗生素吩嗪和硝吡咯菌素或昆虫毒素FitD产生的突变体保留了野生型菌株的杀蚜潜力。然而，缺乏氰化氢（HCN）产生或在调节HCN合成的全局调节因子GacS合成方面有缺陷的突变体产生的挥发物没有杀蚜活性。直接施用氰化钾会导致桃蚜若虫死亡。这些结果表明植物益生菌产生的HCN参与阻止昆虫生长。
