抗菌肽PAF26对采后李果实褐腐菌的抑菌效果及机理

Antibacterial Effect and Mechanism of Antimicrobial Peptide PAF26 on Monilinia fructicola in Postharvest Plums

为了解抗菌肽PAF26处理对采后李果实褐腐菌(Monilinia fructicola)的抑菌效果及可能的抑菌机理,采用离体实验和同孔损伤接种的方法,研究了抗菌肽PAF26对M.fructicola的离体抑菌作用和对李果实褐腐病的控制效果,并测定了抗菌肽对M.fructicola结构完整性的影响和其溶血性。结果表明:PAF26能明显抑制Monilinia fructicola的生长,其最小抑菌浓度为64μmol/L,该浓度下能够明显降低孢子存活率。PAF26也能够有效控制李果实采后褐腐病的发生。经PAF26处理后,染色剂SYTOX Green和碘化丙啶的荧光信号和强度表明,PAF26能增加菌丝和分生孢子膜的通透性。此外,经PAF26处理后的Monilinia fructicola菌丝体胞外电导率显著增加。所选64、128μmol/L的PAF26对人体红细胞几乎没有溶血性。综上,PAF26通过破坏Monilinia fructicola细胞膜结构的完整性,使胞内物质泄漏,加速Monilinia fructicola死亡,从而有效控制李果实采后褐腐病的发生。

This work studied the antibacterial effect and mechanism of antimicrobial peptide PAF26 on Monilinia fructicola in postharvest plums.In this experiment,in vitro experiments and inoculation methods were used to study the antimicrobial peptide PAF26’s in vitro antibacterial effect on M.fructicola and the control effect on plum fruit brown rot.The effect of the antibacterial peptide on the structural integrity of M.fructicola and its hemolytic activity were also tested.The results showed that PAF26 could significantly inhibit the growth of Monilinia fructicola,and its minimum inhibitory concentration(MIC)was 64μmol/L,which could significantly reduce the survival rate of spores.PAF26 could also effectively control the occurrence of Monilinia fructicola in plum fruit.Fluorescent staining with SYTOX Green(SG)and propidium iodide(PI)showed that PAF26 could enhance the permeability of hyphal and conidial membrane.In addition,the extracellular conductivity of Monilinia fructicola mycelia treated with PAF26 was significantly increased.PAF26 at 64 and 128μmol/L hardly resulted in hemolysis of human red blood cells.The above results indicate that PAF26 can effectively control postharvest brown rot in plums by destroying the integrity of the cell membrane structure and consequently accelerating the death of Monilinia fructicola.