抗菌肽Hst5抑制串珠镰刀菌生长及作用机制研究

Inhibitory effect and mechanism of antibacterial peptide Hst5 on Fusarium moniliforme

中文关键词:  抗菌肽  串珠镰刀菌  Hst5  抑制机制

英文关键词:antimicrobial peptide  Fusarium moniliforme  Hst5  inhibition mechanism

中文摘要:

      目的 研究抗菌肽Hst5对串珠镰刀菌的抑制作用, 探究其作用机制。方法 通过扫描电子显微镜、透射电子显微镜、钙荧光白、碘化丙啶、4’,6-二脒基-2-苯基吲哚、线粒体膜电位荧光探针JC-1和2,7-二氯荧光素二乙酸酯等分析不同浓度Hst5处理后的串珠镰刀菌细胞超微结构及胞内氧化还原状态的改变。结果 Hst5处理导致串珠镰刀菌孢子细胞壁破损、细胞膜通透性改变、细胞核受损、细胞器聚集等一系列现象; 同时造成线粒体膜电位下降、琥珀酸脱氢酶和苹果酸脱氢酶酶活性降低及胞内活性氧(reactive oxygen species, ROS)水平升高。结论 Hst5抑制串珠镰刀菌生长是多方面协同作用的结果, 抗菌肽破坏了细胞壁的完整性和细胞膜的通透性, 同时造成线粒体功能紊乱进而导致胞内ROS水平升高、细胞核DNA出现片段化, 最终减弱了串珠镰刀菌在玉米和西红柿中的致病性。本研究为防治串珠镰刀菌提供了新的途径, 为制备新的抗真菌剂奠定一定的理论基础。

英文摘要:

      Objective To study the the inhibitory effect of the antimicrobial peptide Hst5 on Fusarium moniliforme, and explore underlying mechanism of action. Methods The cell ultrastructure and intracellular redox state of Fusarium moniliforme treated with different concentrations of Hst5 were characterized by scanning electron microscope, transmission electron microscope, calcofluor white fluorescent probe, propidium iodide, 4’,6-diamidino-2-phenylindole, mitochondrial membrane potential detection fluorescentprobe JC-1 and 2’,7’-dichlorodihydrofluorescein diacetate, respectively. Results Hst5 treatment resulted in a series of phenomena, such as cell wall and nucleus were damaged, cell membrane permeability was changed, organelles were aggregated. More importantly, the mitochondrial membrane potential, the activities of succinate dehydrogenase and malate dehydrogenase decreased and the level of intracellular reactive oxygen species (ROS) increased. Conclusion The growth inhibition of Fusarium moniliforme by HST5 is the result of multiple synergistic action. Hst5 can destroy the integrity of cell wall and the permeability of cell membrane and cause mitochondrial dysfunction, leading to increased intracellular ROS level, nucleic DNA fragmentation, and ultimately attenuate the pathogenicity of Fusarium moniliforme on corn and tomato. This study provides a new way to control Fusarium moniliforme and theoretical foundation for the development of novel antifungal agents.