一种玉米种子细菌性病原菌的鉴定及其防治药剂筛选

Identification of Aacterial Pathogen of Maize Seeds and Screening of Its Control Agents

为明确一种玉米种子细菌性病原菌,采用平板划线分离法对玉米种子胚芽组织和玉米幼苗心叶组织进行病原菌的分离与纯化,根据柯赫氏法则对其致病性进行测定;结合形态学和分子生物学方法对病原菌进行鉴定;并采用抑菌圈法测定其对5种杀菌剂的敏感性。结果表明,从种子胚芽组织和幼苗心叶生长点组织中分离纯化获得2株培养性状一致的菌株,经柯赫氏法则验证2株菌株是引起玉米矮化皱缩、生长点组织坏死、心叶缺失等症状的病原菌。序列比对结果显示,2株菌株与分散泛菌(Pantoea dispersa)的同源性达到100%,结合菌落形态特性和生理生化特征,将菌株鉴定为Pantoea dispersa。皿内抑菌试验结果表明,0.3%四霉素水剂和47%春雷·王铜可湿性粉剂对菌株YM-001的抑制中浓度EC_(50)分别为670.84μg/mL和920.99μg/mL。

To identify a bacterial pathogen of maize seeds,the method of streaking plate was used to isolate pathogen from the diseased samples collected from germ tissue and seedling leaf tissue of maize seeds.The pathogenicity of the isolates was tested by the Koch’s postulates.Morphological and molecular biological methods were used for pathogen identification.The sensitivity of representative strain to 5 bactericides was also determined by the inhibition zone assay.The results showed that two isolates were obtained from the germ tissue and seedling leaf tissue of maize seeds with similar morphology on medium,and were verified as the pathogens which caused maize dwarfing and shrinkage,growth point necrosis,heart leaf loss.Sequence analysis results showed that the two representative strains reached up to 100%consistent with Pantoea dispersa,combined with the morphological characteristics and physiological and biochemical characteristics of the colony,thus the strains was eventually identified as Pantoea dispersa.The YM-001 strain was sensitive to 0.3%tetramycin AS and 47%Kasugamycin·Copper Chloride WP,its EC_(50) was 670.84μg/mL and 920.99μg/mL.