蓝莓果实黑斑病的病原鉴定及植物精油抑菌研究

为明确山东泰安产区蓝莓采后黑斑病病原菌,通过传统真菌形态学、rDNA-ITS 序列分析,结合构建系统进化发育树,鉴定该病原菌为链格孢菌(Alternaria alternata)。选用肉桂皮、百里香、丁香、柠檬草和玫瑰草5种植物精油对A. alternata进行熏蒸抑菌试验,通过体外抑菌活性筛选出最优的精油类别和作用浓度。体外抑菌结果表明, 5种植物精油对链格孢菌均有不同程度的抑菌活性。其中,肉桂皮精油对A. alternata的抑菌效果最好,其最低抑菌浓度(MIC)和最小杀菌浓度(MFC) 分别为 0.03 μL·mL^-1和0.06 μL·mL^-1。体内接种抑菌试验发现,0.03 μL·mL^-1肉桂皮精油可有效降低蓝莓果实的发病率。扫描电子显微镜(SEM)结果表明,对照组菌丝光滑平整,而经肉桂皮精油处理组,菌丝表面形态受到严重破坏,出现粗糙、褶皱等变形现象。本研究可为山东产区蓝莓贮藏期黑斑病的预防和绿色控制提供一定的参考依据。

Pathogenic Identification of Black Spot Rot on Postharvest Blueberry and Antifungal Activity of Plant Essential Oils

To identify the pathagen of black spot rot in postharvest blueberry in Taian, Shandong province, traditional morphological identification method in combination with rDNA-ITS analysis and phylogenetic tree were conducted on the pathogenic fungal strain isolated from rotten blueberry. The results showed that the strain was identified as Alternaria alternate. Antifungal effects toward A. alternata of five kinds of essential oils including cinnamon, thyme, clove, lemongrass and palmarosa were tested in vitro in order to select the optimum oil specie and concentration. The results showed that all the essential oils exhibited different degree of antifungal activity cinnamon bark oil exhibited the most obvious antifungal effect on Alternaria alternate, and the MIC and MFC were 0.03 μL·mL^-1 and 0.06 μL·mL^-1, respectively. With the concentration of 0.03 μL·mL^-1, cinnamon bark oil could effectively reduce rot incidence after artificial inoculation in vivo. In addition, compared to the control group, the configuration of mycelium treated with cinnamon oil was destroyed with some deformation such as shrinkage and rough appearance through scanning electron microscope (SEM). The results can provide reference for prevention and green control of black spot rot during storage of blueberry in Shandong province.