Khairy Ahmed M, Tohamy Mohamed R A, Zayed Mohamed A, Ali Mohamed A S
Plant Pathology Department, Faculty of Agric, Zagazig Univ, Egypt.
Saudi J Biol Sci. 2021 Sep;28(9):5193-5203. doi: 10.1016/j.sjbs.2021.05.045. Epub 2021 May 24.
Bacterial wilt caused by (Smith), is one of the chief severe diseases of potato in warm temperate regions, tropics and subtropics of the world. The study was conducted to isolate and identify bacterial pathogens and select the most resistant cultivars and avoid the decrease in the total value of Egyptian potato exports to the European Union (EU) due to the quarantine restrictions imposed by the EU on potato tubers exported from Egypt affected by bacterial wilt. The results of traditional identification through morphological and serological studies showed that the five isolates were isolated and identified as . Furthermore, the results illustrated that RS5 isolate showed the lowest percentage of disease incidence reduction on the three tested potatoes cultivar Bellini, Spunta and Mondial recorded 9.64%, 15.41% and 34.12%, respectively. While, RS8 isolate exhibited the highest effective one the percentage of disease reduction on all tested potato cultivars. This isolate reduced disease incidence 60.60%, 63.21% and 71.66%, compering to the healthy control treatment. The result of molecular identification represent that the probe used in Taq-man (PCR) was of the type (B2) capable to detect only biovar 2 of bacterial wilt. Furthermore, primer and probe are specific for detection of the race 3 biovar 2 strain. Positive results were obtained in all assays used including IFAS, protein content and SDS-PAGE with all five isolates. So the isolate (RS5) was the most virulence one, followed by RS1, RS3, RS2 and RS8, registered that the tested isolates were race 3, biovar 2. Also, studies focused on the form of genetic distances and similarities based on pathogenic and plant growth parameters. The results illustrate that the highest genetic similarity (0.998) was found between Bellini and Spunta cultivars as the closest but the lowest value (0.946) was found between Mondial and Bellini as most distant. These results were similarity with genetic distances and SDS-PAGE profile of the three tested potato cultivars
由（史密斯氏菌）引起的青枯病是世界暖温带地区、热带和亚热带地区马铃薯的主要严重病害之一。开展该研究是为了分离和鉴定细菌病原体，选择最具抗性的品种，并避免因欧盟对受青枯病影响的埃及出口马铃薯块茎实施检疫限制而导致埃及马铃薯对欧盟出口总值下降。通过形态学和血清学研究进行传统鉴定的结果表明，分离出了5个菌株并鉴定为（具体菌株名称缺失）。此外，结果表明，RS5菌株在三个受试马铃薯品种贝利尼、斯彭塔和蒙迪阿尔上表现出最低的发病率降低百分比，分别为9.64%、15.41%和34.12%。而RS8菌株在所有受试马铃薯品种上表现出最高的病害降低效果。与健康对照处理相比，该菌株使发病率降低了60.60%、63.21%和71.66%。分子鉴定结果表明，Taq - man（PCR）中使用的探针属于（B2）型，仅能检测青枯病菌的生物变种2。此外，引物和探针对于检测3号生理小种生物变种2菌株具有特异性。在包括间接荧光抗体法（IFAS）、蛋白质含量和十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳（SDS - PAGE）在内的所有使用的检测中，对所有5个菌株都获得了阳性结果。因此，菌株（RS5）的毒力最强，其次是RS1、RS3、RS2和RS8，表明受试菌株为3号生理小种、生物变种2。此外，研究还基于致病和植物生长参数关注了遗传距离和相似性的形式。结果表明，贝利尼和斯彭塔品种之间的遗传相似性最高（0.998），最为接近；而蒙迪阿尔和贝利尼之间的遗传相似性最低（0.946），最为疏远。这些结果与三个受试马铃薯品种的遗传距离和SDS - PAGE图谱相似。
